_artifactcache: There shalt be only one cache sizetristan/fix-cache-exclusivity-1.2

This does a lot of house cleaning, finally bringing cache
cleanup logic to a level of comprehensibility.

Changes in this commit include:

  o _artifactcache/artifactcache.py: _cache_size, _cache_quota and
    _cache_lower_threshold are now all private variables.

    get_approximate_cache_size() is now get_cache_size()

    Added get_quota_exceeded() for the purpose of safely checking
    if we have exceeded the quota.

    set_cache_size() now asserts that the passed size is not None,
    it is not acceptable to set a None size cache anymore.

  o _artifactcache/cascache.py: No longer set the ArtifactCache
    'cache_size' variable violently in the commit() method.

    Also the calculate_cache_size() method now unconditionally
    calculates the cache size, that is what it's for.

  o _scheduler/jobs/cachesizejob.py & _scheduler/jobs/cleanupjob.py:

    Now check the success status. Don't try to set the cache size
    in the case that the job was terminated.

  o _scheduler/jobs/elementjob.py & _scheduler/queues/queue.py:

    No longer passing around the cache size from child tasks,
    this happens only explicitly, not implicitly for all tasks.

  o _scheduler/queues/buildqueue.py & _scheduler/scheduler.py:

    Use get_quota_exceeded() accessor

This is a part of #623

1 files changed, 1 insertions, 6 deletions

diff --git a/buildstream/_artifactcache/cascache.py b/buildstream/_artifactcache/cascache.py
index 099b252a5..4ef8723a3 100644
--- a/buildstream/_artifactcache/cascache.py
+++ b/buildstream/_artifactcache/cascache.py
@@ -120,8 +120,6 @@ class CASCache(ArtifactCache):
         for ref in refs:
             self.set_ref(ref, tree)
 
-        self.cache_size = None
-
     def diff(self, element, key_a, key_b, *, subdir=None):
         ref_a = self.get_artifact_fullname(element, key_a)
         ref_b = self.get_artifact_fullname(element, key_b)
@@ -488,10 +486,7 @@ class CASCache(ArtifactCache):
             raise ArtifactError("Attempt to access unavailable artifact: {}".format(e)) from e
 
     def calculate_cache_size(self):
-        if self.cache_size is None:
-            self.cache_size = utils._get_dir_size(self.casdir)
-
-        return self.cache_size
+        return utils._get_dir_size(self.casdir)
 
     # list_artifacts():
     #