From a8efaab225833ae1a4b0fd46191179079c95b35f Mon Sep 17 00:00:00 2001
From: Tjeerd Jan van der Molen <tjeerdjan.vandermolen@meteogroup.com>
Date: Thu, 23 May 2019 15:39:17 +0200
Subject: [PATCH] Working on jwilder/docker-gen#77

---
 cmd/docker-gen/main.go |  2 +-
 generator.go           | 43 ++++++++++++++++++++++++++++++------------
 2 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/cmd/docker-gen/main.go b/cmd/docker-gen/main.go
index f84546a9..0803c73c 100644
--- a/cmd/docker-gen/main.go
+++ b/cmd/docker-gen/main.go
@@ -96,7 +96,7 @@ func initFlags() {
 	flag.BoolVar(&notifyOutput, "notify-output", false, "log the output(stdout/stderr) of notify command")
 	flag.StringVar(&notifyCmd, "notify", "", "run command after template is regenerated (e.g `restart xyz`)")
 	flag.StringVar(&notifySigHUPContainerID, "notify-sighup", "",
-		"send HUP signal to container.  Equivalent to docker kill -s HUP `container-ID`")
+		"send HUP signal to container. You can either pass a container name/id or a filter key=value to send to multiple containers. Equivalent to docker kill -s HUP `container-ID`")
 	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")
diff --git a/generator.go b/generator.go
index bf68be66..3510cd62 100644
--- a/generator.go
+++ b/generator.go
@@ -126,7 +126,7 @@ func (g *generator) generateFromContainers() {
 			continue
 		}
 		g.runNotifyCmd(config)
-		g.sendSignalToContainer(config)
+		g.sendSignalToContainers(config)
 	}
 }
 
@@ -155,7 +155,7 @@ func (g *generator) generateAtInterval() {
 					// ignore changed return value. always run notify command
 					GenerateFile(config, containers)
 					g.runNotifyCmd(config)
-					g.sendSignalToContainer(config)
+					g.sendSignalToContainers(config)
 				case sig := <-sigChan:
 					log.Printf("Received signal: %s\n", sig)
 					switch sig {
@@ -203,7 +203,7 @@ func (g *generator) generateFromEvents() {
 					continue
 				}
 				g.runNotifyCmd(config)
-				g.sendSignalToContainer(config)
+				g.sendSignalToContainers(config)
 			}
 		}(config, make(chan *docker.APIEvents, 100))
 	}
@@ -323,20 +323,39 @@ func (g *generator) runNotifyCmd(config Config) {
 		}
 	}
 }
+func (g *generator) sendSignalToContainer(containerID string, signal docker.Signal) {
+	log.Printf("Sending container '%s' signal '%v'", containerID, signal)
+	killOpts := docker.KillContainerOptions{
+		ID:     containerID,
+		Signal: signal,
+	}
+	if err := g.Client.KillContainer(killOpts); err != nil {
+		log.Printf("Error sending signal to container: %s", err)
+	}
+}
 
-func (g *generator) sendSignalToContainer(config Config) {
+func (g *generator) sendSignalToContainers(config Config) {
 	if len(config.NotifyContainers) < 1 {
 		return
 	}
-
 	for container, signal := range config.NotifyContainers {
-		log.Printf("Sending container '%s' signal '%v'", container, signal)
-		killOpts := docker.KillContainerOptions{
-			ID:     container,
-			Signal: signal,
-		}
-		if err := g.Client.KillContainer(killOpts); err != nil {
-			log.Printf("Error sending signal to container: %s", err)
+		// Check if the input has a = (filter input requires key/value input) or default back to the old functionality
+		if filterSplit := strings.Split(container, "="); len(filterSplit) > 1 {
+			filters := map[string][]string{}
+			filters[filterSplit[0]] = []string{filterSplit[1]}
+			listOpts := docker.ListContainersOptions{
+				Filters: filters,
+			}
+			containers, err := g.Client.ListContainers(listOpts)
+			if err != nil {
+				log.Printf("Error finding containers to send signal to: %s %s", container, err)
+			}
+			for _, container := range containers {
+				g.sendSignalToContainer(container.ID, signal)
+			}
+
+		} else {
+			g.sendSignalToContainer(container, signal)
 		}
 	}
 }