mgr/cephadm: add custom choose_next_action to ceph exporter service

The ceph exporter service (and similar monitoring stack services)
need to detect if andy dependencies in the mgmt stack support services have
changed and be redeployed if so.

Update the ceph exporter service that makes use of a common function
for checking for this need. A common function will be used instead of
messing around with inheritance because I'm simply not brave enough
to look at doing that and I know a function provides common
implementation without side-effecting the class hierarchy.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

diff --git a/src/pybind/mgr/cephadm/services/cephadmservice.py b/src/pybind/mgr/cephadm/services/cephadmservice.py
index e7344bae95a9b6104a1422d8ddeeaffddb2c1c9f..ee07a5565af391e44cbd7997416edfb27cd85633 100644 (file)
--- a/src/pybind/mgr/cephadm/services/cephadmservice.py
+++ b/src/pybind/mgr/cephadm/services/cephadmservice.py
@@ -1790,6 +1790,24 @@ class CephExporterService(CephService):
 
         return daemon_spec
 
+    manages_own_next_action = True
+
+    def choose_next_action(
+        self,
+        scheduled_action: utils.Action,
+        daemon_type: Optional[str],
+        spec: Optional[ServiceSpec],
+        curr_deps: List[str],
+        last_deps: List[str],
+    ) -> utils.Action:
+        """Given the scheduled_action, service spec, daemon_type, and
+        current and previous dependency lists return the next action that
+        this service would prefer cephadm take.
+        """
+        return next_action_for_mgmt_stack_service(
+            scheduled_action, daemon_type, spec, curr_deps, last_deps
+        )
+
 
 @register_cephadm_service
 class CephfsMirrorService(CephService):
@@ -1887,3 +1905,51 @@ class CephadmAgent(CephService):
         return config, sorted([str(self.mgr.get_mgr_ip()), str(agent.server_port),
                                self.mgr.cert_mgr.get_root_ca(),
                                str(self.mgr.get_module_option('device_enhanced_scan'))])
+
+
+def next_action_for_mgmt_stack_service(
+    scheduled_action: utils.Action,
+    daemon_type: Optional[str],
+    spec: Optional[ServiceSpec],
+    curr_deps: List[str],
+    last_deps: List[str],
+) -> utils.Action:
+    """This function exists to help refactor existing code to use
+    choose_next_action instead of if-blocks inside serve.py.
+    It avoids the need to muck around with common base classes at the
+    cost of some duplication.
+    Call this from choose_next_action.
+    """
+    if curr_deps == last_deps:
+        return scheduled_action
+    sym_diff = set(curr_deps).symmetric_difference(last_deps)
+    logger.info(
+        'Reconfigure wanted %s: deps %r -> %r (diff %r)',
+        spec.service_name() if spec else daemon_type,
+        last_deps,
+        curr_deps,
+        sym_diff,
+    )
+    action = utils.Action.RECONFIG
+    # we need only redeploy if secure_monitoring_stack or mgmt-gateway value has changed:
+    # TODO(redo): check if we should just go always with redeploy (it's fast enough)
+    # TODO(jjm) remove this assert when refactoring process WRT
+    # choose_next_action is done.
+    assert daemon_type in [
+        'prometheus',
+        'node-exporter',
+        'alertmanager',
+        'ceph-exporter',
+    ]
+    REDEPLOY_TRIGGERS = ['secure_monitoring_stack', 'mgmt-gateway']
+    # [from: JJM, to: Redo] in different commits you added calls to
+    # symmetric_difference  for the same variables. I have removed this
+    # duplication but please let me know if I overlooked something WRT
+    # to that in case it was intentional.
+    # Also what is this line below trying to check? I struggle with nested
+    # inline comprehensions but its seems to me you just want to know if
+    # the service newly depends on one of these mgmt stack deps?
+    # If so we ought to be able to vastly simplify this...
+    if any(svc in e for e in sym_diff for svc in REDEPLOY_TRIGGERS):
+        action = utils.Action.REDEPLOY
+    return action