def detect_cause(event: Mapping, **kwargs) -> Cause:
"""
Detect the cause of the event to be handled.
This is a purely computational function with no side-effects.
The causes are then consumed by `custom_object_handler`,
which performs the actual handler invocation, logging, patching,
and other side-effects.
"""
body = event['object']
initial = event[
'type'] is None # special value simulated by us in kopf.reactor.watching.
# The object was really deleted from the cluster. But we do not care anymore.
if event['type'] == 'DELETED':
return Cause(event=GONE, body=body, initial=initial, **kwargs)
# The finalizer has been just removed. We are fully done.
if finalizers.is_deleted(body) and not finalizers.has_finalizers(body):
return Cause(event=FREE, body=body, initial=initial, **kwargs)
if finalizers.is_deleted(body):
return Cause(event=DELETE, body=body, initial=initial, **kwargs)
# For a fresh new object, first block it from accidental deletions without our permission.
# The actual handler will be called on the next call.
if not finalizers.has_finalizers(body):
return Cause(event=NEW, body=body, initial=initial, **kwargs)
# For an object seen for the first time (i.e. just-created), call the creation handlers,
# then mark the state as if it was seen when the creation has finished.
if not lastseen.has_state(body):
return Cause(event=CREATE, body=body, initial=initial, **kwargs)
# Cases with no state changes are usually ignored (NOOP). But for the "None" events,
# as simulated for the initial listing, we call the resuming handlers (e.g. threads/tasks).
if not lastseen.is_state_changed(body) and initial:
return Cause(event=RESUME, body=body, initial=initial, **kwargs)
# The previous step triggers one more patch operation without actual changes. Ignore it.
# Either the last-seen state or the status field has changed.
if not lastseen.is_state_changed(body):
return Cause(event=NOOP, body=body, initial=initial, **kwargs)
# And what is left, is the update operation on one of the useful fields of the existing object.
old, new, diff = lastseen.get_state_diffs(body)
return Cause(event=UPDATE,
body=body,
initial=initial,
diff=diff,
old=old,
new=new,
**kwargs)
def test_state_is_not_changed_with_system_noise():
data = {'spec': {'depth': {'field': 'x'}}}
encoded = json.dumps(data) # json formatting can vary across interpreters
body = {
'metadata': {
'annotations': {
LAST_SEEN_ANNOTATION: encoded
},
'finalizers': ['x', 'y', 'z'],
'generation': 'x',
'resourceVersion': 'x',
'creationTimestamp': 'x',
'deletionTimestamp': 'x',
'uid': 'uid',
},
'status': {
'kopf': {
'progress': 'x',
'anything': 'y'
}
},
'spec': {
'depth': {
'field': 'x'
}
}
}
result = is_state_changed(body=body)
assert isinstance(result, bool)
assert result == False
def test_state_is_changed():
data = {'spec': {'depth': {'field': 'x'}}}
encoded = json.dumps(data) # json formatting can vary across interpreters
body = {'metadata': {'annotations': {LAST_SEEN_ANNOTATION: encoded}}}
result = is_state_changed(body=body)
assert isinstance(result, bool)
assert result == True
async def custom_object_handler(
lifecycle: Callable,
registry: registries.BaseRegistry,
resource: registries.Resource,
event: dict,
freeze: asyncio.Event,
) -> None:
"""
Handle a single custom object low-level watch-event.
Convert the low-level events, as provided by the watching/queueing tasks,
to the high-level causes, and then call the cause-handling logic.
All the internally provoked changes are intercepted, do not create causes,
and therefore do not call the handling logic.
"""
etyp = event['type'] # e.g. ADDED, MODIFIED, DELETED.
body = event['object']
# Each object has its own prefixed logger, to distinguish parallel handling.
logger = ObjectLogger(
logging.getLogger(__name__),
extra=dict(
namespace=body.get('metadata', {}).get('namespace', 'default'),
name=body.get('metadata',
{}).get('name',
body.get('metadata', {}).get('uid', None)),
))
# Object patch accumulator. Populated by the methods. Applied in the end of the handler.
patch = {}
delay = None
# If the global freeze is set for the processing (i.e. other operator overrides), do nothing.
if freeze.is_set():
logger.debug("Ignoring the events due to freeze.")
# The object was really deleted from the cluster. But we do not care anymore.
elif etyp == 'DELETED':
logger.debug("Deleted, really deleted, and we are notified.")
# The finalizer has been just removed. We are fully done.
elif finalizers.is_deleted(body) and not finalizers.has_finalizers(body):
logger.debug(
"Deletion event, but we are done with it, but we do not care.")
elif finalizers.is_deleted(body):
logger.debug("Deletion event: %r", body)
cause = Cause(resource=resource,
event=registries.DELETE,
body=body,
patch=patch,
logger=logger)
try:
await execute(lifecycle=lifecycle, registry=registry, cause=cause)
except HandlerChildrenRetry as e:
# on the top-level, no patches -- it is pre-patched.
delay = e.delay
else:
logger.info(f"All handlers succeeded for deletion.")
events.info(cause.body,
reason='Success',
message=f"All handlers succeeded for deletion.")
logger.debug(
"Removing the finalizer, thus allowing the actual deletion.")
finalizers.remove_finalizers(body=body, patch=patch)
# For a fresh new object, first block it from accidental deletions without our permission.
# The actual handler will be called on the next call.
elif not finalizers.has_finalizers(body):
logger.debug("First appearance: %r", body)
logger.debug(
"Adding the finalizer, thus preventing the actual deletion.")
finalizers.append_finalizers(body=body, patch=patch)
# For the object seen for the first time (i.e. just-created), call the creation handlers,
# then mark the state as if it was seen when the creation has finished.
elif not lastseen.has_state(body):
logger.debug("Creation event: %r", body)
cause = Cause(resource=resource,
event=registries.CREATE,
body=body,
patch=patch,
logger=logger)
try:
await execute(lifecycle=lifecycle, registry=registry, cause=cause)
except HandlerChildrenRetry as e:
# on the top-level, no patches -- it is pre-patched.
delay = e.delay
else:
logger.info(f"All handlers succeeded for creation.")
events.info(cause.body,
reason='Success',
message=f"All handlers succeeded for creation.")
status.purge_progress(body=body, patch=patch)
lastseen.refresh_state(body=body, patch=patch)
# The previous step triggers one more patch operation without actual change. Ignore it.
# Either the last-seen state or the status field has changed.
elif not lastseen.is_state_changed(body):
pass
# And what is left, is the update operation on one of the useful fields of the existing object.
else:
old, new, diff = lastseen.get_state_diffs(body)
logger.debug("Update event: %r", diff)
cause = Cause(resource=resource,
event=registries.UPDATE,
body=body,
patch=patch,
logger=logger,
old=old,
new=new,
diff=diff)
try:
await execute(lifecycle=lifecycle, registry=registry, cause=cause)
except HandlerChildrenRetry as e:
# on the top-level, no patches -- it is pre-patched.
delay = e.delay
else:
logger.info(f"All handlers succeeded for update.")
events.info(cause.body,
reason='Success',
message=f"All handlers succeeded for update.")
status.purge_progress(body=body, patch=patch)
lastseen.refresh_state(body=body, patch=patch)
# Provoke a dummy change to trigger the reactor after sleep.
# TODO: reimplement via the handler delayed statuses properly.
if delay and not patch:
patch.setdefault('kopf',
{})['dummy'] = datetime.datetime.utcnow().isoformat()
# Whatever was done, apply the accumulated changes to the object.
# But only once, to reduce the number of API calls and the generated irrelevant events.
if patch:
logger.debug("Patching with: %r", patch)
patching.patch_obj(resource=resource, patch=patch, body=body)
# Sleep strictly after patching, never before -- to keep the status proper.
if delay:
logger.info(f"Sleeping for {delay} seconds for the delayed handlers.")
await asyncio.sleep(delay)