docker-gen

docker-gen

docker-gen is a file generator that renders templates using docker container meta-data.

docker-gen can be used to generate various kinds of files for:

• Centralized logging - fluentd, logstash or other centralized logging tools that tail the containers JSON log file or files within the container.
• Log Roatation - logrotate files to rotate container JSON log files
• Reverse Proxy Configs - nginx, haproxy, etc. reverse proxy configs to route requests from the host to containers
• Service Discovery - Scripts (python, bash, etc..) to register containers within etcd, hipache, etc..

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Installation

Linux binaries for release 0.1.1

• amd64
• i386

Download the version you need, untar, and install to your PATH.

wget https://github.com/jwilder/docker-gen/releases/download/0.1.1/docker-gen-linux-amd64-0.1.0.tar.gz
tar xvzf tar xvzf docker-gen-linux-amd64-0.1.0.tar.gz
./docker-gen

Usage

docker-gen
Usage: docker-gen [-config file] [-watch=false] [-notify="restart xyz"] [-interval=0] <template> [<dest>]

Options:

• -watch - runs continuously and monitors docker container events. When containers are started or stopped, the template is regenerated.
• -notify - runs a command after the template is generated. Useful for restarting nginx, reloading haproxy, etc..
• -config file - Use the specified config file instead of command-line options. Multiple templates can be defined and they will be executed in the order that they appear in the config file.
• -interval <secs> - Run the notify command on a fixed interval. Useful for service registration use cases.

If no <dest> file is specified, the output is sent to stdout. Mainly useful for debugging.

Examples

NGINX Reverse Proxy Config

docker-gen -only-exposed -watch -notify "/etc/init.d/nginx reload" templates/nginx.tmpl /etc/nginx/sites-enabled/default

Automated Nginx Reverse Proxy for Docker

Fluentd Log Management

docker-gen -watch -notify "restart fluentd" templates/fluentd.tmpl /etc/fluent/fluent.conf

Docker Log Management With Fluentd

Register Containers in Etcd

docker-gen -notify "/bin/bash /tmp/etcd.sh" -interval 10 templates/etcd.tmpl /tmp/etcd.sh

Development

This project uses godep for managing 3rd party dependencies. You'll need to install godep into your workspace before hacking on docker-gen.

git clone <your fork>
godep restore
make

TODO

• Add Dockerfile and trusted build
• Add event status for handling start and stop events differently
• Add a way to filter out containers in templates