feat: filter containers to notify

README.md

@@ -101,9 +101,14 @@ Options:
       log the output(stdout/stderr) of notify command
   -notify-container container-ID
       container to send a signal to
+  -notify-filter key=value
+      container filter for notification (e.g -notify-filter name=foo).
+      You can have multiple of these.
+      https://docs.docker.com/engine/reference/commandline/ps/#filter
   -notify-signal signal
-      signal to send to the -notify-container. -1 to call docker restart. Defaults to 1 aka. HUP.
-      All available signals available on the [dockerclient](https://github.com/fsouza/go-dockerclient/blob/01804dec8a84d0a77e63611f2b62d33e9bb2b64a/signal.go)
+      signal to send to the -notify-container and -notify-filter. -1 to call docker restart. Defaults to 1 aka. HUP.
+      All available signals available on the dockerclient
+      https://github.com/fsouza/go-dockerclient/blob/01804dec8a84d0a77e63611f2b62d33e9bb2b64a/signal.go
   -notify-sighup container-ID
       send HUP signal to container.  Equivalent to 'docker kill -s HUP container-ID', or `-notify-container container-ID -notify-signal 1`
   -only-exposed

cmd/docker-gen/main.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	"strings"
 	"syscall"
 
 	"github.com/BurntSushi/toml"
@@ -16,6 +17,7 @@ import (
 )
 
 type stringslice []string
+type mapstringslice map[string][]string
 
 var (
 	buildVersion          string
@@ -26,6 +28,7 @@ var (
 	notifyOutput          bool
 	notifyContainerID     string
 	notifyContainerSignal int
+	notifyContainerFilter mapstringslice = make(mapstringslice)
 	onlyExposed           bool
 	onlyPublished         bool
 	includeStopped        bool
@@ -50,6 +53,18 @@ func (strings *stringslice) Set(value string) error {
 	return nil
 }
 
+func (filter *mapstringslice) String() string {
+	return "[string][]string"
+}
+
+func (filter *mapstringslice) Set(value string) error {
+	name, value, found := strings.Cut(value, "=")
+	if found {
+		(*filter)[name] = append((*filter)[name], value)
+	}
+	return nil
+}
+
 func usage() {
 	println(`Usage: docker-gen [options] template [dest]
 
@@ -100,8 +115,10 @@ func initFlags() {
 		"send HUP signal to container.  Equivalent to docker kill -s HUP `container-ID`")
 	flag.StringVar(&notifyContainerID, "notify-container", "",
 		"container to send a signal to")
+	flag.Var(&notifyContainerFilter, "notify-filter",
+		"container filter for notification (e.g -notify-filter name=foo). You can have multiple of these. https://docs.docker.com/engine/reference/commandline/ps/#filter")
 	flag.IntVar(&notifyContainerSignal, "notify-signal", int(docker.SIGHUP),
-		"signal to send to the notify-container. Defaults to SIGHUP")
+		"signal to send to the notify-container and notify-filter. Defaults to SIGHUP")
 	flag.Var(&configFiles, "config", "config files with template directives. Config files will be merged if this option is specified multiple times.")
 	flag.IntVar(&interval, "interval", 0, "notify command interval (secs)")
 	flag.BoolVar(&keepBlankLines, "keep-blank-lines", false, "keep blank lines in the output file")
@@ -161,6 +178,10 @@ func main() {
 		if notifyContainerID != "" {
 			cfg.NotifyContainers[notifyContainerID] = notifyContainerSignal
 		}
+		if len(notifyContainerFilter) > 0 {
+			cfg.NotifyContainersFilter = notifyContainerFilter
+			cfg.NotifyContainersSignal = notifyContainerSignal
+		}
 		configs = config.ConfigFile{
 			Config: []config.Config{cfg}}
 	}

internal/config/config.go

@@ -7,18 +7,20 @@ import (
 )
 
 type Config struct {
-	Template         string
-	Dest             string
-	Watch            bool
-	Wait             *Wait
-	NotifyCmd        string
-	NotifyOutput     bool
-	NotifyContainers map[string]int
-	OnlyExposed      bool
-	OnlyPublished    bool
-	IncludeStopped   bool
-	Interval         int
-	KeepBlankLines   bool
+	Template               string
+	Dest                   string
+	Watch                  bool
+	Wait                   *Wait
+	NotifyCmd              string
+	NotifyOutput           bool
+	NotifyContainers       map[string]int
+	NotifyContainersFilter map[string][]string
+	NotifyContainersSignal int
+	OnlyExposed            bool
+	OnlyPublished          bool
+	IncludeStopped         bool
+	Interval               int
+	KeepBlankLines         bool
 }
 
 type ConfigFile struct {

internal/generator/generator.go

@@ -132,7 +132,8 @@ func (g *generator) generateFromContainers() {
 			continue
 		}
 		g.runNotifyCmd(config)
-		g.sendSignalToContainer(config)
+		g.sendSignalToContainers(config)
+		g.sendSignalToFilteredContainers(config)
 	}
 }
 
@@ -162,7 +163,8 @@ func (g *generator) generateAtInterval() {
 					// ignore changed return value. always run notify command
 					template.GenerateFile(cfg, containers)
 					g.runNotifyCmd(cfg)
-					g.sendSignalToContainer(cfg)
+					g.sendSignalToContainers(cfg)
+					g.sendSignalToFilteredContainers(cfg)
 				case sig := <-sigChan:
 					log.Printf("Received signal: %s\n", sig)
 					switch sig {
@@ -210,7 +212,8 @@ func (g *generator) generateFromEvents() {
 					continue
 				}
 				g.runNotifyCmd(cfg)
-				g.sendSignalToContainer(cfg)
+				g.sendSignalToContainers(cfg)
+				g.sendSignalToFilteredContainers(cfg)
 			}
 		}(cfg)
 	}
@@ -332,28 +335,50 @@ func (g *generator) runNotifyCmd(config config.Config) {
 	}
 }
 
-func (g *generator) sendSignalToContainer(config config.Config) {
+func (g *generator) sendSignalToContainer(container string, signal int) {
+	log.Printf("Sending container '%s' signal '%v'", container, signal)
+
+	if signal == -1 {
+		if err := g.Client.RestartContainer(container, 10); err != nil {
+			log.Printf("Error sending restarting container: %s", err)
+		}
+		return
+	}
+
+	killOpts := docker.KillContainerOptions{
+		ID:     container,
+		Signal: docker.Signal(signal),
+	}
+	if err := g.Client.KillContainer(killOpts); err != nil {
+		log.Printf("Error sending signal to container: %s", err)
+	}
+}
+
+func (g *generator) sendSignalToContainers(config config.Config) {
 	if len(config.NotifyContainers) < 1 {
 		return
 	}
 
 	for container, signal := range config.NotifyContainers {
-		log.Printf("Sending container '%s' signal '%v'", container, signal)
+		g.sendSignalToContainer(container, signal)
+	}
+}
 
-		if signal == -1 {
-			if err := g.Client.RestartContainer(container, 10); err != nil {
-				log.Printf("Error sending restarting container: %s", err)
-			}
-			return
-		}
+func (g *generator) sendSignalToFilteredContainers(config config.Config) {
+	if len(config.NotifyContainersFilter) < 1 {
+		return
+	}
 
-		killOpts := docker.KillContainerOptions{
-			ID:     container,
-			Signal: docker.Signal(signal),
-		}
-		if err := g.Client.KillContainer(killOpts); err != nil {
-			log.Printf("Error sending signal to container: %s", err)
-		}
+	containers, err := g.Client.ListContainers(docker.ListContainersOptions{
+		Filters: config.NotifyContainersFilter,
+	})
+	if err != nil {
+		log.Printf("Error getting containers: %s", err)
+		return
+	}
+
+	for _, container := range containers {
+		g.sendSignalToContainer(container.ID, config.NotifyContainersSignal)
 	}
 }