Cron tab: crontabs, cron.d, user crontabs, run-parts dirs and systemd timers in one list; next/last run, run now, enable/disable, in-place editing, cron log and output file
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
This commit is contained in:
Mitchell-Johnson
co-authored by
Claude Fable 5.1
Claude Fable 5.1
parent
bc891b1042
commit
41c2f05535
@@ -0,0 +1,761 @@
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// Package cron reads every scheduled job on the host into one list: /etc/crontab,
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// /etc/cron.d/*, per-user crontabs, the run-parts directories they drive, and systemd
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// timers. It computes next runs from the cron expressions, pulls last runs from the
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// journal (cron logs "(user) CMD (command)" via syslog), and can toggle, edit and run
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// jobs. Reads/writes that need root go through passwordless sudo when available.
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package cron
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import (
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"bufio"
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"bytes"
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"context"
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"crypto/sha1"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"os"
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"os/exec"
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"os/user"
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"path/filepath"
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"regexp"
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"sort"
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"strconv"
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"strings"
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"sync"
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"time"
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)
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type Job struct {
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ID string `json:"id"`
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Source string `json:"source"` // "/etc/crontab", "/etc/cron.d/x", "crontab:user", "/etc/cron.daily"
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Line int `json:"line"` // 1-based line in Source (0 for run-parts scripts)
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User string `json:"user"`
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Schedule string `json:"schedule"`
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Command string `json:"command"`
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Enabled bool `json:"enabled"`
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Next int64 `json:"next,omitempty"` // unix ms
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Last int64 `json:"last,omitempty"`
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OutFile string `json:"out_file,omitempty"` // parsed from a ">> file" redirect
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Note string `json:"note,omitempty"`
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Editable bool `json:"editable"`
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raw string
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}
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type Timer struct {
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Unit string `json:"unit"`
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Activates string `json:"activates"`
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Description string `json:"description"`
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Active string `json:"active"`
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Sub string `json:"sub"`
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Enabled string `json:"enabled"`
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Next int64 `json:"next,omitempty"`
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Last int64 `json:"last,omitempty"`
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}
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type Overview struct {
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Jobs []Job `json:"jobs"`
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Timers []Timer `json:"timers"`
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Logging bool `json:"logging"` // cron lines seen in the journal
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Anacron bool `json:"anacron"`
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Sudo bool `json:"sudo"`
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}
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type Run struct {
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ID string `json:"id"`
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JobID string `json:"job_id"`
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Command string `json:"command"`
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User string `json:"user"`
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Started time.Time `json:"started"`
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Finished time.Time `json:"finished,omitempty"`
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Running bool `json:"running"`
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ExitCode int `json:"exit_code"`
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Output string `json:"output"`
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mu sync.Mutex
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buf bytes.Buffer
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}
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type Manager struct {
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sudo bool
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journalSudo bool
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self string
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mu sync.Mutex
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lastRuns map[string]int64 // user\x00command -> unix ms
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lastAt time.Time
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logging bool
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runs map[string]*Run
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}
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func New(sudo, journalSudo bool) *Manager {
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m := &Manager{sudo: sudo, journalSudo: journalSudo, runs: map[string]*Run{}}
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if u, err := user.Current(); err == nil {
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m.self = u.Username
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}
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return m
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}
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// ---- helpers ----
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func run(ctx context.Context, stdin string, args ...string) (string, error) {
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ctx, cancel := context.WithTimeout(ctx, 20*time.Second)
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defer cancel()
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cmd := exec.CommandContext(ctx, args[0], args[1:]...)
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if stdin != "" {
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cmd.Stdin = strings.NewReader(stdin)
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}
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var out, errb bytes.Buffer
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cmd.Stdout, cmd.Stderr = &out, &errb
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if err := cmd.Run(); err != nil {
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msg := strings.TrimSpace(errb.String())
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if msg == "" {
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msg = err.Error()
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}
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return out.String(), errors.New(msg)
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}
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return out.String(), nil
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}
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func (m *Manager) sudoArgs(args ...string) []string {
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if m.sudo {
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return append([]string{"sudo", "-n"}, args...)
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}
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return args
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}
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func jobID(source, raw string) string {
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h := sha1.Sum([]byte(source + "\n" + raw))
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return hex.EncodeToString(h[:6])
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}
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var userRe = regexp.MustCompile(`^[a-z_][a-z0-9_-]{0,31}$`)
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var cronDName = regexp.MustCompile(`^[A-Za-z0-9_-]+$`) // cron ignores other names in /etc/cron.d
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// ---- parsing ----
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// parseLine splits one crontab line. withUser is true for system crontabs (6th field is
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// the user). Returns ok=false for comments, blanks, env assignments and garbage.
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func parseLine(line string, withUser bool) (schedule, usr, command string, ok bool) {
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t := strings.TrimSpace(line)
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if t == "" || strings.HasPrefix(t, "#") {
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return
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}
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if i := strings.Index(t, "="); i > 0 && !strings.ContainsAny(t[:i], " \t*") { // NAME=value
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return
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}
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var fields []string
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if strings.HasPrefix(t, "@") {
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f := strings.Fields(t)
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if len(f) < 2 {
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return
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}
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fields = []string{f[0]}
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t = strings.TrimSpace(t[len(f[0]):])
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} else {
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f := strings.Fields(t)
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if len(f) < 6 {
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return
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}
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fields = f[:5]
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for _, x := range fields {
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t = strings.TrimSpace(t[len(x):])
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}
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}
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schedule = strings.Join(fields, " ")
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if _, err := parseSchedule(schedule); err != nil {
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return
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}
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if withUser {
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f := strings.Fields(t)
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if len(f) < 2 || !userRe.MatchString(f[0]) {
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return
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}
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usr = f[0]
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t = strings.TrimSpace(t[len(f[0]):])
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}
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if t == "" {
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return
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}
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return schedule, usr, t, true
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}
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var redirectRe = regexp.MustCompile(`(?:^|\s)(?:>>|>|2>&1\s*>>|&>>|&>)\s*("?)([^\s"&|;]+)`)
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func outFile(cmd string) string {
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for _, m := range redirectRe.FindAllStringSubmatch(cmd, -1) {
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if p := m[2]; strings.HasPrefix(p, "/") && p != "/dev/null" {
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return p
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}
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}
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return ""
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}
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// parseSource turns crontab text into jobs. Commented-out lines that still parse as a
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// job are reported disabled, so a "# 0 5 * * * ..." example shows up as such.
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func (m *Manager) parseSource(source, text string, withUser, editable bool, defaultUser string, now time.Time, anacron bool) []Job {
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var jobs []Job
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lines := strings.Split(text, "\n")
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isComment := func(i int) bool {
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return i >= 0 && i < len(lines) && strings.HasPrefix(strings.TrimSpace(lines[i]), "#")
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}
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for i, line := range lines {
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enabled := true
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probe := line
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if t := strings.TrimSpace(line); strings.HasPrefix(t, "#") {
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// A commented-out job sits on its own; a job-shaped line inside a block of
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// comments is documentation (Debian's stock header has two such examples).
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if isComment(i-1) && isComment(i+1) {
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continue
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}
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enabled = false
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probe = strings.TrimLeft(t, "# ")
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}
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schedule, usr, command, ok := parseLine(probe, withUser)
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if !ok {
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continue
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}
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if usr == "" {
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usr = defaultUser
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}
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if !enabled {
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if _, err := user.Lookup(usr); err != nil {
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continue // "user-name" placeholder and the like
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}
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}
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j := Job{ID: jobID(source, line), Source: source, Line: i + 1, User: usr, Schedule: schedule, Command: command,
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Enabled: enabled, OutFile: outFile(command), Editable: editable, raw: line}
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if enabled {
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if next, ok := nextRun(schedule, now); ok {
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j.Next = next.UnixMilli()
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}
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}
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if strings.Contains(command, "run-parts") {
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if dir := runPartsDir(command); dir != "" {
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if anacron && strings.Contains(command, "anacron") {
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j.Note = "skipped: anacron is installed and runs " + dir + " instead"
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}
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jobs = append(jobs, j)
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jobs = append(jobs, m.runPartsJobs(dir, j)...)
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continue
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}
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}
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jobs = append(jobs, j)
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}
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return jobs
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}
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var runPartsRe = regexp.MustCompile(`run-parts\s+(?:--\S+\s+)*(/\S+)`)
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func runPartsDir(cmd string) string {
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if m := runPartsRe.FindStringSubmatch(cmd); m != nil {
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return m[1]
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}
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return ""
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}
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// runPartsJobs lists the executable scripts a run-parts line will run, as read-only jobs.
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func (m *Manager) runPartsJobs(dir string, parent Job) []Job {
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ents, err := os.ReadDir(dir)
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if err != nil {
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return nil
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}
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var out []Job
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for _, e := range ents {
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if e.IsDir() || !cronDName.MatchString(e.Name()) {
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continue
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}
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info, err := e.Info()
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if err != nil || info.Mode()&0o111 == 0 {
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continue
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}
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p := filepath.Join(dir, e.Name())
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out = append(out, Job{ID: jobID(dir, e.Name()), Source: dir, User: parent.User, Schedule: parent.Schedule, Command: p,
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Enabled: parent.Enabled, Next: parent.Next, Note: "run by " + parent.Source + " via run-parts", raw: e.Name()})
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}
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return out
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}
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// ---- sources ----
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type source struct {
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name string // job Source
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withUser bool
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user string // default user for user crontabs
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editable bool
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}
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func (m *Manager) readSource(ctx context.Context, s source) (string, error) {
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if strings.HasPrefix(s.name, "crontab:") {
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u := s.user
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if u == m.self {
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out, err := run(ctx, "", "crontab", "-l")
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if err != nil && strings.Contains(err.Error(), "no crontab") {
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return "", nil
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}
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return out, err
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}
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if !m.sudo {
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return "", errors.New("needs sudo")
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}
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out, err := run(ctx, "", "sudo", "-n", "crontab", "-u", u, "-l")
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if err != nil && strings.Contains(err.Error(), "no crontab") {
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return "", nil
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}
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return out, err
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}
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b, err := os.ReadFile(s.name)
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if err != nil && m.sudo {
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out, err2 := run(ctx, "", "sudo", "-n", "cat", s.name)
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return out, err2
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}
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return string(b), err
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}
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func (m *Manager) sources(ctx context.Context) []source {
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var out []source
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if _, err := os.Stat("/etc/crontab"); err == nil {
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out = append(out, source{name: "/etc/crontab", withUser: true, editable: m.sudo})
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}
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if ents, err := os.ReadDir("/etc/cron.d"); err == nil {
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for _, e := range ents {
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if !e.IsDir() && cronDName.MatchString(e.Name()) {
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out = append(out, source{name: "/etc/cron.d/" + e.Name(), withUser: true, editable: m.sudo})
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}
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}
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}
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// per-user crontabs: Debian keeps them in /var/spool/cron/crontabs, cronie in /var/spool/cron
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users := map[string]bool{}
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if m.sudo {
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for _, dir := range []string{"/var/spool/cron/crontabs", "/var/spool/cron"} {
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if out, err := run(ctx, "", "sudo", "-n", "ls", "-1", dir); err == nil {
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for _, n := range strings.Split(out, "\n") {
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if n = strings.TrimSpace(n); userRe.MatchString(n) {
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users[n] = true
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}
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}
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break
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}
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}
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}
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if m.self != "" {
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users[m.self] = true
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}
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names := make([]string, 0, len(users))
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for u := range users {
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names = append(names, u)
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}
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sort.Strings(names)
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for _, u := range names {
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out = append(out, source{name: "crontab:" + u, user: u, editable: u == m.self || m.sudo})
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}
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return out
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}
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func (m *Manager) findSource(ctx context.Context, name string) (source, bool) {
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for _, s := range m.sources(ctx) {
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if s.name == name {
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return s, true
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}
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}
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return source{}, false
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}
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// ---- overview ----
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func (m *Manager) Overview(ctx context.Context) Overview {
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now := time.Now()
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_, anacronErr := os.Stat("/usr/sbin/anacron")
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anacron := anacronErr == nil
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ov := Overview{Jobs: []Job{}, Timers: []Timer{}, Anacron: anacron, Sudo: m.sudo}
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for _, s := range m.sources(ctx) {
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text, err := m.readSource(ctx, s)
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if err != nil {
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continue
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}
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ov.Jobs = append(ov.Jobs, m.parseSource(s.name, text, s.withUser, s.editable, s.user, now, anacron)...)
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}
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last := m.lastRunsFromJournal(ctx)
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ov.Logging = m.logging
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for i := range ov.Jobs {
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j := &ov.Jobs[i]
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if t, ok := last[j.User+"\x00"+j.Command]; ok {
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j.Last = t
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}
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}
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ov.Timers = m.timers(ctx)
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return ov
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}
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var cronLogRe = regexp.MustCompile(`^\((\S+)\) CMD \((.*)\)$`)
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// lastRunsFromJournal maps user+command to the most recent "(user) CMD (command)" line.
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func (m *Manager) lastRunsFromJournal(ctx context.Context) map[string]int64 {
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m.mu.Lock()
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if time.Since(m.lastAt) < 60*time.Second && m.lastRuns != nil {
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r := m.lastRuns
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m.mu.Unlock()
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return r
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}
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m.mu.Unlock()
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args := []string{"journalctl", "-t", "CRON", "-t", "cron", "-t", "crond", "-o", "json", "--no-pager", "-q", "--since", "-30d", "-n", "20000"}
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if m.journalSudo {
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args = append([]string{"sudo", "-n"}, args...)
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}
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out, _ := run(ctx, "", args...)
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res := map[string]int64{}
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seen := false
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sc := bufio.NewScanner(strings.NewReader(out))
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sc.Buffer(make([]byte, 0, 64<<10), 4<<20)
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for sc.Scan() {
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var raw struct {
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Msg any `json:"MESSAGE"`
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TS string `json:"__REALTIME_TIMESTAMP"`
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}
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if json.Unmarshal(sc.Bytes(), &raw) != nil {
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continue
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}
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seen = true
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msg, _ := raw.Msg.(string)
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mm := cronLogRe.FindStringSubmatch(msg)
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if mm == nil {
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continue
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}
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us, _ := strconv.ParseInt(raw.TS, 10, 64)
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k := mm[1] + "\x00" + mm[2]
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if us/1000 > res[k] {
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res[k] = us / 1000
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}
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}
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m.mu.Lock()
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m.lastRuns, m.lastAt, m.logging = res, time.Now(), seen
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m.mu.Unlock()
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return res
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}
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// JobLogs returns the journal lines for one job's command (most recent last).
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func (m *Manager) JobLogs(ctx context.Context, j Job, n int) ([]map[string]any, error) {
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args := []string{"journalctl", "-t", "CRON", "-t", "cron", "-t", "crond", "-o", "json", "--no-pager", "-q", "-n", "20000"}
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if m.journalSudo {
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args = append([]string{"sudo", "-n"}, args...)
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}
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out, err := run(ctx, "", args...)
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if err != nil {
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return nil, err
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}
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var res []map[string]any
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sc := bufio.NewScanner(strings.NewReader(out))
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sc.Buffer(make([]byte, 0, 64<<10), 4<<20)
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for sc.Scan() {
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var raw struct {
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Msg any `json:"MESSAGE"`
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TS string `json:"__REALTIME_TIMESTAMP"`
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PID string `json:"_PID"`
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}
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if json.Unmarshal(sc.Bytes(), &raw) != nil {
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continue
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}
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msg, _ := raw.Msg.(string)
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if !strings.Contains(msg, "("+j.User+") CMD ("+j.Command+")") {
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continue
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}
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us, _ := strconv.ParseInt(raw.TS, 10, 64)
|
||||
res = append(res, map[string]any{"t": us / 1000, "p": 6, "ident": "CRON", "pid": raw.PID, "msg": msg})
|
||||
}
|
||||
if len(res) > n {
|
||||
res = res[len(res)-n:]
|
||||
}
|
||||
if res == nil {
|
||||
res = []map[string]any{}
|
||||
}
|
||||
return res, nil
|
||||
}
|
||||
|
||||
// OutputTail returns the last n lines of the job's redirect target.
|
||||
func (m *Manager) OutputTail(ctx context.Context, j Job, n int) (string, error) {
|
||||
if j.OutFile == "" {
|
||||
return "", errors.New("job has no output file")
|
||||
}
|
||||
out, err := run(ctx, "", m.sudoArgs("tail", "-n", strconv.Itoa(n), j.OutFile)...)
|
||||
return out, err
|
||||
}
|
||||
|
||||
// ---- timers ----
|
||||
|
||||
func (m *Manager) timers(ctx context.Context) []Timer {
|
||||
out, err := run(ctx, "", "systemctl", "list-timers", "--all", "--output=json", "--no-pager")
|
||||
if err != nil {
|
||||
return []Timer{}
|
||||
}
|
||||
var lt []struct {
|
||||
Next int64 `json:"next"`
|
||||
Last int64 `json:"last"`
|
||||
Unit string `json:"unit"`
|
||||
Activates string `json:"activates"`
|
||||
}
|
||||
_ = json.Unmarshal([]byte(out), <)
|
||||
units, _ := run(ctx, "", "systemctl", "list-units", "--type=timer", "--all", "--output=json", "--no-pager", "--plain")
|
||||
var lu []struct{ Unit, Active, Sub, Description string }
|
||||
_ = json.Unmarshal([]byte(units), &lu)
|
||||
meta := map[string]struct{ Active, Sub, Description string }{}
|
||||
for _, u := range lu {
|
||||
meta[u.Unit] = struct{ Active, Sub, Description string }{u.Active, u.Sub, u.Description}
|
||||
}
|
||||
files, _ := run(ctx, "", "systemctl", "list-unit-files", "--type=timer", "--output=json", "--no-pager")
|
||||
var uf []struct {
|
||||
UnitFile string `json:"unit_file"`
|
||||
State string `json:"state"`
|
||||
}
|
||||
_ = json.Unmarshal([]byte(files), &uf)
|
||||
enabled := map[string]string{}
|
||||
for _, f := range uf {
|
||||
enabled[f.UnitFile] = f.State
|
||||
}
|
||||
res := make([]Timer, 0, len(lt))
|
||||
for _, t := range lt {
|
||||
x := Timer{Unit: t.Unit, Activates: t.Activates, Enabled: enabled[t.Unit]}
|
||||
if mt, ok := meta[t.Unit]; ok {
|
||||
x.Active, x.Sub, x.Description = mt.Active, mt.Sub, mt.Description
|
||||
}
|
||||
if t.Next > 0 {
|
||||
x.Next = t.Next / 1000
|
||||
}
|
||||
if t.Last > 0 {
|
||||
x.Last = t.Last / 1000
|
||||
}
|
||||
res = append(res, x)
|
||||
}
|
||||
sort.Slice(res, func(i, j int) bool { return res[i].Unit < res[j].Unit })
|
||||
return res
|
||||
}
|
||||
|
||||
var timerRe = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9@._:\\-]{0,255}\.timer$`)
|
||||
|
||||
func (m *Manager) TimerAction(ctx context.Context, unit, action string) error {
|
||||
if !timerRe.MatchString(unit) {
|
||||
return errors.New("invalid timer name")
|
||||
}
|
||||
switch action {
|
||||
case "start", "stop", "enable", "disable":
|
||||
_, err := run(ctx, "", m.sudoArgs("systemctl", action, unit)...)
|
||||
return err
|
||||
case "run": // fire the service the timer activates, right now
|
||||
out, err := run(ctx, "", "systemctl", "show", unit, "-p", "Triggers", "--value")
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
svc := strings.TrimSpace(strings.Split(out, " ")[0])
|
||||
if svc == "" {
|
||||
return errors.New("timer triggers nothing")
|
||||
}
|
||||
_, err = run(ctx, "", m.sudoArgs("systemctl", "start", svc)...)
|
||||
return err
|
||||
}
|
||||
return errors.New("unknown action")
|
||||
}
|
||||
|
||||
// ---- job lookup and editing ----
|
||||
|
||||
func (m *Manager) FindJob(ctx context.Context, id string) (Job, bool) {
|
||||
for _, j := range m.Overview(ctx).Jobs {
|
||||
if j.ID == id {
|
||||
return j, true
|
||||
}
|
||||
}
|
||||
return Job{}, false
|
||||
}
|
||||
|
||||
// Source returns a crontab's raw text for the editor.
|
||||
func (m *Manager) Source(ctx context.Context, name string) (text string, editable bool, err error) {
|
||||
s, ok := m.findSource(ctx, name)
|
||||
if !ok {
|
||||
return "", false, errors.New("unknown source")
|
||||
}
|
||||
text, err = m.readSource(ctx, s)
|
||||
return text, s.editable, err
|
||||
}
|
||||
|
||||
// validate rejects any line that is neither blank, comment, env assignment, nor a job.
|
||||
func validate(text string, withUser bool) error {
|
||||
for i, line := range strings.Split(text, "\n") {
|
||||
t := strings.TrimSpace(line)
|
||||
if t == "" || strings.HasPrefix(t, "#") {
|
||||
continue
|
||||
}
|
||||
if k, _, ok := strings.Cut(t, "="); ok && !strings.ContainsAny(strings.TrimSpace(k), " \t*") {
|
||||
continue
|
||||
}
|
||||
if _, _, _, ok := parseLine(t, withUser); !ok {
|
||||
return fmt.Errorf("line %d: not a valid cron entry", i+1)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// WriteSource replaces a crontab. User crontabs go through crontab(1) so cron reloads
|
||||
// them; system files are written in place with their permissions preserved.
|
||||
func (m *Manager) WriteSource(ctx context.Context, name, text string) error {
|
||||
s, ok := m.findSource(ctx, name)
|
||||
if !ok {
|
||||
return errors.New("unknown source")
|
||||
}
|
||||
if !s.editable {
|
||||
return errors.New("source is read-only here (no sudo)")
|
||||
}
|
||||
if !strings.HasSuffix(text, "\n") {
|
||||
text += "\n"
|
||||
}
|
||||
if err := validate(text, s.withUser); err != nil {
|
||||
return err
|
||||
}
|
||||
if strings.HasPrefix(name, "crontab:") {
|
||||
if s.user == m.self {
|
||||
_, err := run(ctx, text, "crontab", "-")
|
||||
return err
|
||||
}
|
||||
_, err := run(ctx, text, "sudo", "-n", "crontab", "-u", s.user, "-")
|
||||
return err
|
||||
}
|
||||
if name != "/etc/crontab" && !strings.HasPrefix(name, "/etc/cron.d/") {
|
||||
return errors.New("refusing to write outside /etc/crontab and /etc/cron.d")
|
||||
}
|
||||
_, err := run(ctx, text, "sudo", "-n", "tee", name)
|
||||
m.mu.Lock()
|
||||
m.lastAt = time.Time{}
|
||||
m.mu.Unlock()
|
||||
return err
|
||||
}
|
||||
|
||||
// Toggle comments or uncomments a job's line. The line must still read as the job did
|
||||
// when it was listed, so a concurrent edit can't be clobbered.
|
||||
func (m *Manager) Toggle(ctx context.Context, j Job, enable bool) error {
|
||||
if j.Line == 0 || !j.Editable {
|
||||
return errors.New("this job can't be toggled here")
|
||||
}
|
||||
s, ok := m.findSource(ctx, j.Source)
|
||||
if !ok {
|
||||
return errors.New("unknown source")
|
||||
}
|
||||
text, err := m.readSource(ctx, s)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
lines := strings.Split(text, "\n")
|
||||
if j.Line > len(lines) || lines[j.Line-1] != j.raw {
|
||||
return errors.New("crontab changed underneath; reload and try again")
|
||||
}
|
||||
if enable {
|
||||
lines[j.Line-1] = strings.TrimLeft(strings.TrimSpace(j.raw), "# ")
|
||||
} else {
|
||||
lines[j.Line-1] = "#" + j.raw
|
||||
}
|
||||
return m.WriteSource(ctx, j.Source, strings.Join(lines, "\n"))
|
||||
}
|
||||
|
||||
// ---- run now ----
|
||||
|
||||
// StartRun executes the job's command as its user, the way cron would (sh -c, cwd = home,
|
||||
// '%' turned into newlines/stdin), in the background. Output is kept in memory.
|
||||
func (m *Manager) StartRun(ctx context.Context, j Job) (*Run, error) {
|
||||
if j.User != m.self && !m.sudo {
|
||||
return nil, errors.New("needs sudo to run as " + j.User)
|
||||
}
|
||||
cmdline, stdin := cronPercent(j.Command)
|
||||
args := []string{"sh", "-c", cmdline}
|
||||
if j.User != m.self {
|
||||
args = append([]string{"sudo", "-n", "-u", j.User, "-H"}, args...)
|
||||
}
|
||||
r := &Run{ID: jobID("run", strconv.FormatInt(time.Now().UnixNano(), 10)), JobID: j.ID, Command: j.Command, User: j.User, Started: time.Now(), Running: true}
|
||||
runCtx, cancel := context.WithTimeout(context.Background(), 30*time.Minute)
|
||||
cmd := exec.CommandContext(runCtx, args[0], args[1:]...)
|
||||
if stdin != "" {
|
||||
cmd.Stdin = strings.NewReader(stdin)
|
||||
}
|
||||
w := &capWriter{r: r}
|
||||
cmd.Stdout, cmd.Stderr = w, w
|
||||
if err := cmd.Start(); err != nil {
|
||||
cancel()
|
||||
return nil, err
|
||||
}
|
||||
m.mu.Lock()
|
||||
m.runs[r.ID] = r
|
||||
for id, old := range m.runs { // keep the map small
|
||||
if !old.Running && time.Since(old.Finished) > time.Hour {
|
||||
delete(m.runs, id)
|
||||
}
|
||||
}
|
||||
m.mu.Unlock()
|
||||
go func() {
|
||||
defer cancel()
|
||||
err := cmd.Wait()
|
||||
r.mu.Lock()
|
||||
r.Running, r.Finished = false, time.Now()
|
||||
if err != nil {
|
||||
if ee, ok := err.(*exec.ExitError); ok {
|
||||
r.ExitCode = ee.ExitCode()
|
||||
} else {
|
||||
r.ExitCode = -1
|
||||
}
|
||||
}
|
||||
r.mu.Unlock()
|
||||
m.mu.Lock()
|
||||
m.lastAt = time.Time{}
|
||||
m.mu.Unlock()
|
||||
}()
|
||||
return r, nil
|
||||
}
|
||||
|
||||
func (m *Manager) GetRun(id string) (*Run, bool) {
|
||||
m.mu.Lock()
|
||||
r, ok := m.runs[id]
|
||||
m.mu.Unlock()
|
||||
return r, ok
|
||||
}
|
||||
|
||||
// Snapshot returns a copy safe to encode.
|
||||
func (r *Run) Snapshot() Run {
|
||||
r.mu.Lock()
|
||||
defer r.mu.Unlock()
|
||||
return Run{ID: r.ID, JobID: r.JobID, Command: r.Command, User: r.User, Started: r.Started, Finished: r.Finished,
|
||||
Running: r.Running, ExitCode: r.ExitCode, Output: r.buf.String()}
|
||||
}
|
||||
|
||||
type capWriter struct{ r *Run }
|
||||
|
||||
func (w *capWriter) Write(p []byte) (int, error) {
|
||||
w.r.mu.Lock()
|
||||
defer w.r.mu.Unlock()
|
||||
w.r.buf.Write(p)
|
||||
if w.r.buf.Len() > 256<<10 { // keep the tail
|
||||
b := w.r.buf.Bytes()
|
||||
w.r.buf = *bytes.NewBuffer(append([]byte("…\n"), b[len(b)-200<<10:]...))
|
||||
}
|
||||
return len(p), nil
|
||||
}
|
||||
|
||||
// cronPercent applies crontab(5) rules: an unescaped % ends the command; later ones are
|
||||
// newlines fed to stdin. "\%" is a literal percent.
|
||||
func cronPercent(cmd string) (string, string) {
|
||||
var out, in strings.Builder
|
||||
cur := &out
|
||||
esc := false
|
||||
for _, c := range cmd {
|
||||
switch {
|
||||
case esc:
|
||||
if c != '%' {
|
||||
cur.WriteRune('\\')
|
||||
}
|
||||
cur.WriteRune(c)
|
||||
esc = false
|
||||
case c == '\\':
|
||||
esc = true
|
||||
case c == '%':
|
||||
if cur == &out {
|
||||
cur = &in
|
||||
} else {
|
||||
in.WriteRune('\n')
|
||||
}
|
||||
default:
|
||||
cur.WriteRune(c)
|
||||
}
|
||||
}
|
||||
return out.String(), in.String()
|
||||
}
|
||||
@@ -0,0 +1,163 @@
|
||||
package cron
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"strconv"
|
||||
"strings"
|
||||
"time"
|
||||
)
|
||||
|
||||
// schedule is a parsed five-field cron expression as sets.
|
||||
type schedule struct {
|
||||
min, hour, dom, mon, dow [64]bool
|
||||
domStar, dowStar bool // "*" in dom/dow changes the match rule
|
||||
reboot bool
|
||||
}
|
||||
|
||||
var monthNames = map[string]int{"jan": 1, "feb": 2, "mar": 3, "apr": 4, "may": 5, "jun": 6, "jul": 7, "aug": 8, "sep": 9, "oct": 10, "nov": 11, "dec": 12}
|
||||
var dayNames = map[string]int{"sun": 0, "mon": 1, "tue": 2, "wed": 3, "thu": 4, "fri": 5, "sat": 6}
|
||||
|
||||
var aliases = map[string]string{
|
||||
"@yearly": "0 0 1 1 *", "@annually": "0 0 1 1 *", "@monthly": "0 0 1 * *", "@weekly": "0 0 * * 0",
|
||||
"@daily": "0 0 * * *", "@midnight": "0 0 * * *", "@hourly": "0 * * * *",
|
||||
}
|
||||
|
||||
func parseSchedule(expr string) (*schedule, error) {
|
||||
expr = strings.TrimSpace(expr)
|
||||
if expr == "@reboot" {
|
||||
return &schedule{reboot: true}, nil
|
||||
}
|
||||
if a, ok := aliases[strings.ToLower(expr)]; ok {
|
||||
expr = a
|
||||
}
|
||||
f := strings.Fields(expr)
|
||||
if len(f) != 5 {
|
||||
return nil, errors.New("expected 5 fields")
|
||||
}
|
||||
s := &schedule{}
|
||||
var err error
|
||||
if s.min, err = parseField(f[0], 0, 59, nil); err != nil {
|
||||
return nil, fmt.Errorf("minute: %w", err)
|
||||
}
|
||||
if s.hour, err = parseField(f[1], 0, 23, nil); err != nil {
|
||||
return nil, fmt.Errorf("hour: %w", err)
|
||||
}
|
||||
if s.dom, err = parseField(f[2], 1, 31, nil); err != nil {
|
||||
return nil, fmt.Errorf("day of month: %w", err)
|
||||
}
|
||||
if s.mon, err = parseField(f[3], 1, 12, monthNames); err != nil {
|
||||
return nil, fmt.Errorf("month: %w", err)
|
||||
}
|
||||
if s.dow, err = parseField(f[4], 0, 7, dayNames); err != nil {
|
||||
return nil, fmt.Errorf("day of week: %w", err)
|
||||
}
|
||||
if s.dow[7] { // 7 == Sunday
|
||||
s.dow[0] = true
|
||||
}
|
||||
s.domStar = f[2] == "*"
|
||||
s.dowStar = f[4] == "*"
|
||||
return s, nil
|
||||
}
|
||||
|
||||
func parseField(field string, lo, hi int, names map[string]int) ([64]bool, error) {
|
||||
var set [64]bool
|
||||
atom := func(s string) (int, error) {
|
||||
if names != nil {
|
||||
if v, ok := names[strings.ToLower(s)]; ok {
|
||||
return v, nil
|
||||
}
|
||||
}
|
||||
v, err := strconv.Atoi(s)
|
||||
if err != nil {
|
||||
return 0, fmt.Errorf("bad value %q", s)
|
||||
}
|
||||
return v, nil
|
||||
}
|
||||
for _, part := range strings.Split(field, ",") {
|
||||
step := 1
|
||||
if i := strings.Index(part, "/"); i >= 0 {
|
||||
v, err := strconv.Atoi(part[i+1:])
|
||||
if err != nil || v <= 0 {
|
||||
return set, fmt.Errorf("bad step in %q", part)
|
||||
}
|
||||
step, part = v, part[:i]
|
||||
}
|
||||
a, b := lo, hi
|
||||
switch {
|
||||
case part == "*":
|
||||
case strings.Contains(part, "-"):
|
||||
x, y, _ := strings.Cut(part, "-")
|
||||
var err error
|
||||
if a, err = atom(x); err != nil {
|
||||
return set, err
|
||||
}
|
||||
if b, err = atom(y); err != nil {
|
||||
return set, err
|
||||
}
|
||||
default:
|
||||
v, err := atom(part)
|
||||
if err != nil {
|
||||
return set, err
|
||||
}
|
||||
a = v
|
||||
if step == 1 {
|
||||
b = v
|
||||
}
|
||||
}
|
||||
if a < lo || b > hi || a > b {
|
||||
return set, fmt.Errorf("out of range: %q", part)
|
||||
}
|
||||
for v := a; v <= b; v += step {
|
||||
set[v] = true
|
||||
}
|
||||
}
|
||||
return set, nil
|
||||
}
|
||||
|
||||
func (s *schedule) dayMatches(t time.Time) bool {
|
||||
if !s.mon[int(t.Month())] {
|
||||
return false
|
||||
}
|
||||
dom, dow := s.dom[t.Day()], s.dow[int(t.Weekday())]
|
||||
switch {
|
||||
case s.domStar && s.dowStar:
|
||||
return true
|
||||
case s.domStar:
|
||||
return dow
|
||||
case s.dowStar:
|
||||
return dom
|
||||
default: // both restricted: cron runs when either matches
|
||||
return dom || dow
|
||||
}
|
||||
}
|
||||
|
||||
// nextRun finds the first time strictly after `from` that the schedule fires.
|
||||
func nextRun(expr string, from time.Time) (time.Time, bool) {
|
||||
s, err := parseSchedule(expr)
|
||||
if err != nil || s.reboot {
|
||||
return time.Time{}, false
|
||||
}
|
||||
t := from.Truncate(time.Minute).Add(time.Minute)
|
||||
day := time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, t.Location())
|
||||
for i := 0; i < 366*2; i++ {
|
||||
if s.dayMatches(day) {
|
||||
for h := 0; h < 24; h++ {
|
||||
if !s.hour[h] {
|
||||
continue
|
||||
}
|
||||
for mi := 0; mi < 60; mi++ {
|
||||
if !s.min[mi] {
|
||||
continue
|
||||
}
|
||||
c := time.Date(day.Year(), day.Month(), day.Day(), h, mi, 0, 0, day.Location())
|
||||
if !c.Before(t) {
|
||||
return c, true
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
day = day.AddDate(0, 0, 1)
|
||||
}
|
||||
return time.Time{}, false
|
||||
}
|
||||
@@ -0,0 +1,68 @@
|
||||
package cron
|
||||
|
||||
import (
|
||||
"testing"
|
||||
"time"
|
||||
)
|
||||
|
||||
func TestNextRun(t *testing.T) {
|
||||
loc := time.UTC
|
||||
from := time.Date(2026, 9, 17, 15, 30, 0, 0, loc) // Thursday
|
||||
cases := []struct {
|
||||
expr string
|
||||
want time.Time
|
||||
}{
|
||||
{"0 1 * * *", time.Date(2026, 9, 18, 1, 0, 0, 0, loc)},
|
||||
{"17 * * * *", time.Date(2026, 9, 17, 16, 17, 0, 0, loc)},
|
||||
{"*/15 * * * *", time.Date(2026, 9, 17, 15, 45, 0, 0, loc)},
|
||||
{"47 6 * * 7", time.Date(2026, 9, 20, 6, 47, 0, 0, loc)}, // Sunday as 7
|
||||
{"52 6 1 * *", time.Date(2026, 10, 1, 6, 52, 0, 0, loc)}, // first of month
|
||||
{"24 0 1-7 * *", time.Date(2026, 10, 1, 0, 24, 0, 0, loc)}, // range
|
||||
{"30 3 * * 0", time.Date(2026, 9, 20, 3, 30, 0, 0, loc)}, // Sunday as 0
|
||||
{"0 9 15 * mon", time.Date(2026, 9, 21, 9, 0, 0, 0, loc)}, // dom OR dow
|
||||
{"@daily", time.Date(2026, 9, 18, 0, 0, 0, 0, loc)},
|
||||
{"@weekly", time.Date(2026, 9, 20, 0, 0, 0, 0, loc)},
|
||||
{"0 0 29 feb *", time.Date(2028, 2, 29, 0, 0, 0, 0, loc)},
|
||||
}
|
||||
for _, c := range cases {
|
||||
got, ok := nextRun(c.expr, from)
|
||||
if !ok || !got.Equal(c.want) {
|
||||
t.Errorf("%q: got %v ok=%v, want %v", c.expr, got, ok, c.want)
|
||||
}
|
||||
}
|
||||
if _, ok := nextRun("@reboot", from); ok {
|
||||
t.Error("@reboot should have no next run")
|
||||
}
|
||||
for _, bad := range []string{"* * * *", "60 * * * *", "a b c d e", "*/0 * * * *"} {
|
||||
if _, err := parseSchedule(bad); err == nil {
|
||||
t.Errorf("%q should fail", bad)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestParseLine(t *testing.T) {
|
||||
sch, u, cmd, ok := parseLine("25 6\t* * *\troot\ttest -x /usr/sbin/anacron || { cd / && run-parts --report /etc/cron.daily; }", true)
|
||||
if !ok || sch != "25 6 * * *" || u != "root" || !strings_HasPrefix(cmd, "test -x") {
|
||||
t.Errorf("system line: %q %q %q %v", sch, u, cmd, ok)
|
||||
}
|
||||
if _, _, _, ok := parseLine("PATH=/usr/bin:/bin", true); ok {
|
||||
t.Error("env line parsed as job")
|
||||
}
|
||||
if _, _, _, ok := parseLine("# m h dom mon dow command", false); ok {
|
||||
t.Error("comment parsed as job")
|
||||
}
|
||||
if _, u, cmd, ok := parseLine("@reboot /usr/local/bin/thing --flag", false); !ok || u != "" || cmd != "/usr/local/bin/thing --flag" {
|
||||
t.Errorf("@reboot: %q %q %v", u, cmd, ok)
|
||||
}
|
||||
if got := outFile("foo >> /var/log/foo.log 2>&1"); got != "/var/log/foo.log" {
|
||||
t.Errorf("outFile: %q", got)
|
||||
}
|
||||
if c, in := cronPercent("echo hi%line1%line2"); c != "echo hi" || in != "line1\nline2" {
|
||||
t.Errorf("percent: %q %q", c, in)
|
||||
}
|
||||
if c, _ := cronPercent(`date +\%w`); c != "date +%w" {
|
||||
t.Errorf("escaped percent: %q", c)
|
||||
}
|
||||
}
|
||||
|
||||
func strings_HasPrefix(s, p string) bool { return len(s) >= len(p) && s[:len(p)] == p }
|
||||
Reference in New Issue
Block a user