supervisord-dependent-startup is a plugin for
Supervisor that allows starting up services after
other services have reached specific states. This plugin is based on
ordered-startup-supervisord
by Jason Corbett.
The problem can be seen in supervisor bug
#122. The priority order
in supervisor does determine startup order, but when autostart=true supervisor
doesn't wait for the previous process to be RUNNING in order to continue. What
is even harder is having initialization scripts that need to exit before
continuing. This software is meant to make this one use case easier.
This is an event listener for supervisor. This means it is run by supervisor on startup and supervisor will send it messages whenever a service reaches a particular process state. When configured it will wait till a supervisor subprocess gets to the configured state before starting dependent services.
The plugin does not start groups. It can start services that are part of a group, but it won't directly start a group.
Configuration requires several things. First you need to configure
supervisord-dependent-startup in supervisor.conf as an event listener.
[eventlistener:dependentstartup]
command=/path/to/supervisord-dependent-startup
autostart=true
events=PROCESS_STATEThere are three configuration options for a service ([program:*]) to control
how it is processed by supervisord-dependent-startup
Mark this service to be handled by supervisord-dependent-startup. This must be
set to true for all services that depend on other services or is being
depended on by other services.
| Type | bool |
|---|---|
| Required | yes |
| Note | When setting this to true, autostart must be set to false |
Specify the services this service depends on before in can be started.
| Type | str |
|---|---|
| Required | no |
| Format | dependent_startup_wait_for=<parent-service>:<state[,state[..]]> [..] |
| Note | state must one or more comma separated values of: starting, running, backoff, stopping, exited, fatal |
To have a service named child depend on a service parent:
dependent_startup_wait_for=parent:running
Multiple dependencies are separated by a white space. To have a service named
child depend on the services parent1 and parent2:
dependent_startup_wait_for=parent1:running parent2:running
Specify if the service should inherit its priority from the services it depends on.
| Type | bool |
|---|---|
| Required | no |
| Example | dependent_startup_inherit_priority=true |
python setup.py testpython setup.py sdisttox