Initial commit

.gitignore

@@ -0,0 +1 @@
+docker-gen

Makefile

@@ -0,0 +1,9 @@
+.SILENT :
+.PHONY : docker-gen clean fmt
+
+all: docker-gen
+
+docker-gen:
+	echo "Building docker-gen"
+	go build
+

README.md

@@ -0,0 +1,18 @@
+docker-gen
+=====
+
+Config file generator using running docker container meta-data.
+
+This is mostly a proof of concept to generate config files for:
+
+ * fluentd, logstash or other centralized logging tools that tail the containers JSON log file.
+ * logrotate files to rotate container JSON log files
+
+ `go get github.com/jwilder/docker-gen`
+
+ `docker-gen template.file`
+
+TODO:
+
+ * Restart command hooks for when files are regenerated
+ * Tail docker event stream to detect when containers are started and stopped automatically

docker-gen.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"github.com/fsouza/go-dockerclient"
+	"os"
+	"path/filepath"
+	"text/template"
+)
+
+func usage() {
+	println("Usage: docker-log template.file")
+}
+
+func generateFile(templatePath string, containers []docker.APIContainers) {
+	tmpl, err := template.ParseFiles(templatePath)
+	if err != nil {
+		panic(err)
+	}
+
+	err = tmpl.ExecuteTemplate(os.Stdout, filepath.Base(templatePath), containers)
+}
+
+func main() {
+
+	if len(os.Args) != 2 {
+		usage()
+		os.Exit(1)
+	}
+
+	endpoint := "unix:///var/run/docker.sock"
+	client, err := docker.NewClient(endpoint)
+
+	if err != nil {
+		panic(err)
+	}
+
+	containers, err := client.ListContainers(docker.ListContainersOptions{
+		All: false,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	generateFile(os.Args[1], containers)
+}

templates/fluentd.conf.tmpl

@@ -0,0 +1,20 @@
+
+## File input
+## read docker logs with tag=docker.container
+
+{{range $key, $value := .}}
+<source>
+  type tail
+  format json
+  time_key time
+  path /var/lib/docker/containers/{{ $value.ID }}/{{ $value.ID }}-json.log
+  pos_file /var/lib/docker/containers/{{ $value.ID }}/{{ $value.ID }}-json.log.pos
+  tag docker.container.{{printf "%.*s" 12 $value.ID}}
+  rotate_wait 5
+</source>
+{{end}}
+
+<match docker.**>
+  type stdout
+</match>
+