supervisor-stdout

A simple supervisord event listener to relay process output to supervisor's stdout.

This is useful in situations where the output will be collected and set to external logging framework, such as Heroku, Docker, Kubernetes, or AWS ECS/Fargate.

Installation

Just install via pip or add to your requirements.txt:

pip install supervisor-stdout

Installation for Docker

If you're building a Docker container and you find Linux distro has outdated supervisor packages, that the pip supervisor-stdout package is very outdated, that venv makes pip use difficult, and that pipx install doesn't work because supervisord can't resolve the handler name, then you might like to forceably install the latest version from github as follows.

RUN pip install git+https://github.com/Supervisor/supervisor.git --break-system-packages && \
    pip install git+https://github.com/coderanger/supervisor-stdout.git --break-system-packages

If you find that the 'coderanger/supervisor-stdout' repo hasn't merged this pull request, then can use this person's fork as follows.

RUN pip install git+https://github.com/Supervisor/supervisor.git --break-system-packages && \
    pip install git+git+https://github.com/whereisaaron/supervisor-stdout.git --break-system-packages

Usage

An example supervisord.conf:

[supervisord]
nodaemon = true
logfile=/dev/null
logfile_maxbytes=0

[program:web]
command = ...
stdout_events_enabled = true
stderr_events_enabled = true
stdout_logfile = NONE
stderr_logfile = NONE

[eventlistener:stdout]
command = supervisor_stdout
buffer_size = 100
events = PROCESS_LOG
result_handler = supervisor_stdout:event_handler
stdout_logfile = NONE
stderr_logfile = NONE

Advanced Usage

The default event_handler prefixes log lines with the process name and channel, e.g. apache stderr | <your log line here>

If you would prefer simpler prefix, or no prefix at all, you can use the alternative hander names process_event_handler and plain_event_handler.

process_event_handler prefixes logs line with just the process name, e.g. apache | <your log line here>.

[eventlistener:stdout]
command = supervisor_stdout
buffer_size = 100
events = PROCESS_LOG
result_handler = supervisor_stdout:process_event_handler
stdout_logfile = NONE
stderr_logfile = NONE

plain_event_handler passed the log line unaltered, without any prefix, e.g. <your log line here>.

[eventlistener:stdout]
command = supervisor_stdout
buffer_size = 100
events = PROCESS_LOG
result_handler = supervisor_stdout:plain_event_handler
stdout_logfile = NONE
stderr_logfile = NONE

Change Log

Forked from @coderanger's excellent supervisor-stdout plug-in at the following commit.

https://github.com/coderanger/supervisor-stdout/commit/973ba19967cdaf46d9c1634d1675fc65b9574f6e

Changes:

• Eliminated the blank line emitted after every log line
• Eliminated the block buffering lag that delayed log lines being relayed to supervisor's stdout
• Added alternative handler names that enable relaying log lines unaltered, or with only the process name.

Breaking Changes:

• None, remain compatible with original forked version