docker-entrypoint

Production-ready entrypoint shell script for Docker, for launching one or more processes within a single docker container.

It allows you to:

• enforce and control the use of mandatory environment variables

• define optional environment variables with default values

• move files from a location to another for pre-start purposes

• build template configuration files that will be rewritten pre-start with the content of your environment variables (requires a writeable /tmp in your container)

• launch an unlimited number of processes, with optional sleep policy before starting specific processes

• implement flexible Stop conditions on crashes or processes exits: kill all the other processes (gracefully or not), restart the crashed process, ignore, execute custom command, etc.

• execute pre-start and post-start commands for additional setup processes with optional sleep policy again

• implement a global stop policy, to gracefully handle external container termination (docker stop, CTRL+C, etc.)

• flush an unlimited number files on stdout - Useful for lazy real time log extraction on stdout rather than trying to change application/servers configs to print on stdout. Warning: flushed files are truncated

• have a RESET feature, allowing you to execute specific set of commands only when you define $RESET_CONTAINER in environment

• handles arguments on docker run so that you can override the entrypoint (eg: to start a shell) - supports parameters.

• internal detailed documentation explaining all the steps for exploiting the features

TODO (if you want to contribute):

• conditional pre-start, entrypoint and post-start pipelines rather than sleep based executions
• a support for executing specific processes under specific user ids
• a rewrite of the file replacement feature which works but could be more elegant and could avoid using /tmp
• more constants to permit an easier behavior edition on some features
• alternative to flush-truncate with a tail