Change mutex to counting semaphore
The mutex in zuul is great but is limited to run one job at the same
time. Some use cases like using a limited number floating licenses in
jobs cannot be handled with this. Thus this changes the mutex
functionality to a counting semaphore (which defaults to 1).
This is a port of Ida589e49bc6694f4ccc4c586e0d43b391b8c3ae4 to zuulv3
branch.
Change-Id: Icf4013a6215e2b10ca8e6309928b9e5881dda02c
diff --git a/doc/source/zuul.rst b/doc/source/zuul.rst
index e4ce737..d41ed89 100644
--- a/doc/source/zuul.rst
+++ b/doc/source/zuul.rst
@@ -644,10 +644,12 @@
would largely defeat the parallelization of dependent change testing
that is the main feature of Zuul. Default: ``false``.
-**mutex (optional)**
- This is a string that names a mutex that should be observed by this
- job. Only one build of any job that references the same named mutex
- will be enqueued at a time. This applies across all pipelines.
+**semaphore (optional)**
+ This is a string that names a semaphore that should be observed by this
+ job. The semaphore defines how many jobs which reference that semaphore
+ can be enqueued at a time. This applies across all pipelines in the same
+ tenant. The max value of the semaphore can be specified in the config
+ repositories and defaults to 1.
**branch (optional)**
This job should only be run on matching branches. This field is
@@ -850,6 +852,21 @@
or specified in the project itself, the configuration defined by
either the last template or the project itself will take priority.
+
+Semaphores
+""""""""""
+
+When using semaphores the maximum value of each one can be specified in their
+respective config repositories. Unspecified semaphores default to 1::
+
+ - semaphore:
+ name: semaphore-foo
+ max: 5
+ - semaphore:
+ name: semaphore-bar
+ max: 3
+
+
logging.conf
~~~~~~~~~~~~
This file is optional. If provided, it should be a standard