Utility to simplify running applications in docker containers.
dockerize is a utility to simplify running applications in docker containers. It allows you to generate application configuration files at container startup time from templates and container environment variables. It also allows log files to be tailed to stdout and/or stderr.
The typical use case for dockerize is when you have an application that has one or more configuration files and you would like to control some of the values using environment variables.
For example, a Python application using Sqlalchemy may be able to use environment variables directly.
It may require that the database URL be read from a python settings file with a variable named
SQLALCHEMY_DATABASE_URI. dockerize allows you to set an environment variable such as
DATABASE_URL and update the python file when the container starts.
Another use case is when the application logs to specific files on the filesystem and not stdout
or stderr. This makes it difficult to troubleshoot the container using the docker logs command.
For example, nginx will log to `/var/log/nginx/access.log' and
'/var/log/nginx/error.log' by default. While you can sometimes work around this, it's tedious to find
the a solution for every application. dockerize allows you to specify which logs files should
be tailed and where they should be sent.
See A Simple Way To Dockerize Applications
Download the latest version in your container:
For Ubuntu Images:
RUN apt-get update && apt-get install -y wget
RUN wget https://github.com/jwilder/dockerize/releases/download/v0.0.1/dockerize-linux-amd64-v0.0.1.tar.gz
RUN tar -C /usr/local/bin -xzvf dockerize-linux-amd64-v0.0.1.tar.gz
dockerize works by wrapping the call to your application using the ENTRYPOINT or CMD directives.
This would generate /etc/nginx/nginx.conf from the template located at /etc/nginx/nginx.tmpl and
send /var/log/nginx/access.log' to STDOUTand/var/log/nginx/error.logtoSTDERRafter runningnginx`.
CMD dockerize -template /etc/nginx/nginx.tmpl:/etc/nginx/nginx.conf -stdout /var/log/nginx/access.log -stderr /var/log/nginx/error.log nginx
You can specify multiple template by passing using -template multiple times:
$ dockerize -template template1.tmpl:file1.cfg -template template2.tmpl:file3
You can tail multiple files to STDOUT and STDERR by passing the options multiple times.
$ dockerize -stdout info.log -stdout perf.log
If your file uses {{ and }} as part of it's syntax, you can change the template escape characters using the -delims.
$ dockerize -delims "<%:%>"
Templates use Golang text/template. You can access environment
variables within a template with .Env.
{{ .Env.PATH }} is my path
There are a few built in functions as well:
default- Returns a default value for one that does not existcontains- Returns true if a string is within another stringexists- Determines if a file path exists or notsplit- Splits a string into an array using a separator stringreplace- Replaces all occurences of a string within another stringparseUrl- Parses a URL into it's protocol, scheme, host, etc. parts.
MIT