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Add PID file support #1733

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Add PID file support #1733

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31 changes: 31 additions & 0 deletions snapteld.go
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Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,11 @@ var (
Usage: fmt.Sprintf("1-5 (Debug, Info, Warning, Error, Fatal; default: %v)", defaultLogLevel),
EnvVar: "SNAP_LOG_LEVEL",
}
flPIDFile = cli.StringFlag{
Name: "pid-file, pidfile, P",
Usage: "File to write PID of snapteld, if set.",
EnvVar: "SNAP_PID_FILE",
}
flConfig = cli.StringFlag{
Name: "config",
Usage: "A path to a config file",
Expand Down Expand Up @@ -127,6 +132,7 @@ type Config struct {
LogPath string `json:"log_path,omitempty"yaml:"log_path,omitempty"`
LogTruncate bool `json:"log_truncate,omitempty"yaml:"log_truncate,omitempty"`
LogColors bool `json:"log_colors,omitempty"yaml:"log_colors,omitempty"`
PIDFile string `json:"pid_file,omitempty"yaml:"pid_file,omitempty"`
Control *control.Config `json:"control,omitempty"yaml:"control,omitempty"`
Scheduler *scheduler.Config `json:"scheduler,omitempty"yaml:"scheduler,omitempty"`
RestAPI *rest.Config `json:"restapi,omitempty"yaml:"restapi,omitempty"`
Expand Down Expand Up @@ -162,6 +168,10 @@ const (
"type": "integer",
"minimum": 1
},
"pid_file": {
"description": "file for snpateld to write PID",
"type": "string"
},
"control": { "$ref": "#/definitions/control" },
"scheduler": { "$ref": "#/definitions/scheduler"},
"restapi" : { "$ref": "#/definitions/restapi"},
Expand Down Expand Up @@ -219,6 +229,7 @@ func main() {
flLogTruncate,
flLogColors,
flMaxProcs,
flPIDFile,
flConfig,
}
cliApp.Flags = append(cliApp.Flags, control.Flags...)
Expand Down Expand Up @@ -323,6 +334,25 @@ func action(ctx *cli.Context) error {
// Set Max Processors for snapteld.
setMaxProcs(cfg.GoMaxProcs)

// Write PID file, if configured.
log.Info("Config PID file", cfg.PIDFile)
if cfg.PIDFile != "" {
log.Info("Creating PID file", cfg.PIDFile)
f, err := os.OpenFile(cfg.PIDFile, os.O_CREATE|os.O_WRONLY, 0644)
if err != nil {
log.Error("Unable to create pidfile", err)
} else {
fmt.Fprintf(f, "%d\n", os.Getpid())
f.Close()
defer func() {
err := os.Remove(cfg.PIDFile)
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Sorry, I have a stupid question to ask.
Why delete the PIDFile?

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Most servers are expected to delete their PID file when the server shuts down — for example, Apache removes its PID file when shutting down.

However, since snapteld calls os.Exit() when it shuts down, I recently realized that this deferred function will not be executed, since os.Exit shuts down immediately without calling deferred functions.

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@cce
Thanks for your explanation!
Yes, I think the the actual behavior is not your meaning.
Could you please update this PR according your design when you are free?

if err != nil {
log.Error("Unable to remove pidfile", err)
}
}()
}
}

c := control.New(cfg.Control)
if c.Config.AutoDiscoverPath != "" && c.Config.IsTLSEnabled() {
log.Fatal("TLS security is not supported in autodiscovery mode")
Expand Down Expand Up @@ -843,6 +873,7 @@ func applyCmdLineFlags(cfg *Config, ctx runtimeFlagsContext) {
cfg.LogPath = setStringVal(cfg.LogPath, ctx, "log-path")
cfg.LogTruncate = setBoolVal(cfg.LogTruncate, ctx, "log-truncate")
cfg.LogColors = setBoolVal(cfg.LogColors, ctx, "log-colors")
cfg.PIDFile = setStringVal(cfg.PIDFile, ctx, "pid-file")
// next for the flags related to the control package
cfg.Control.MaxRunningPlugins = setIntVal(cfg.Control.MaxRunningPlugins, ctx, "max-running-plugins")
cfg.Control.PluginLoadTimeout = setIntVal(cfg.Control.PluginLoadTimeout, ctx, "plugin-load-timeout")
Expand Down
2 changes: 2 additions & 0 deletions snapteld_test.go
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Expand Up @@ -43,6 +43,7 @@ var validCmdlineFlags_input = mockFlags{
"log-path": "/no/logs/allowed",
"log-truncate": "true",
"log-colors": "true",
"pid-file": "/no/pidfile/here",
"max-running-plugins": "12",
"plugin-load-timeout": "20",
"plugin-trust": "1",
Expand Down Expand Up @@ -118,6 +119,7 @@ var validCmdlineFlags_expected = &Config{
LogPath: "/no/logs/allowed",
LogTruncate: true,
LogColors: true,
PIDFile: "/no/pidfile/here",
}

func TestSnapConfig(t *testing.T) {
Expand Down