August 4th, 2015
(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: email@example.com
A [program:x] section actually represents a “homogeneous process group” to supervisor (as of 3.0). The members of the group are defined by the combination of the numprocs and process_name parameters in the configuration. By default, if numprocs and process_name are left unchanged from their defaults, the group represented by [program:x] will be named x and will have a single process named x in it. This provides a modicum of backwards compatibility with older supervisor releases, which did not treat program sections as homogeneous process group definitions.
But for instance, if you have a [program:foo] section with a numprocs of 3 and a process_name expression of %(program_name)s_%(process_num)02d, the “foo” group will contain three processes, named foo_00, foo_01, and foo_02. This makes it possible to start a number of very similar processes using a single [program:x] section. All logfile names, all environment strings, and the command of programs can also contain similar Python string expressions, to pass slightly different parameters to each process.