.. Ross Patterson's Blog imported post, created by `$ ./bin/rfc822-to-post` on Mar 15, 2021.

.. meta::
   :description: Poor man's supervisor program startup delay
   :keywords: Plone, Zope

.. post:: Jun 04, 2009
   :tags: Plone, Zope
   :author: Ross Patterson
   :redirect:  @@redirect-to-uuid/efa992d2acaa8139af035c99a406f71f

###################
Stagger supervisord
###################

    Poor man's supervisor program startup delay

Update
------

The right way to solve my original problem concerning ConflictErrors
when starting up multiple ZEO clients and subsequent TypeErrors, as
pointed out by both Hanno Schlichting and Martijn Pieters, is to add
the following to the configuration of all but the first ZEO client::

  zope-conf-additional +=
      enable-product-installation False

Here's the genericized post in case someone needs supervisor
staggering for some other reason.

Staggering
----------

Thanks to some discussion with aclark and dukebody and some previous
experience abusing zc.recipe.egg to add hackish scripts to a buildout,
I came up with a solution.  Adding the following part to a buildout
will add a "bin/sleep NUM COMMAND ARGS..." script that will sleep for
NUM seconds and then call COMMAND with ARGS::

    [sleep]
    recipe = zc.recipe.egg
    eggs = zc.recipe.egg
    initialization =
        import sys, time
        time.sleep(float(sys.argv[1]))
    arguments = sys.argv[2], sys.argv[2:]
    entry-points = sleep=os:execvp

This script can then be used in etc/supervisor.conf::

    [program:foo]
    command = %(here)s/../bin/foo
    startsecs = 30
    
    [program:foo2]
    command = %(here)s/../bin/sleep 30 %(here)s/../bin/foo2
    startsecs = 60
    
    [program:foo3]
    command = %(here)s/../bin/sleep 60 %(here)s/../bin/foo3
    startsecs = 90
    
    [program:foo4]
    command = %(here)s/../bin/sleep 90 %(here)s/../bin/foo4
    startsecs = 120

Now bin/supervisord will stagger the startup of all foo* programs and
prevent them from running afoul of each other.


.. update:: Jun 04, 2009

   Imported from Plone on Mar 15, 2021.  The date for this update is the last
   modified date in Plone.