chore(debugging): general coding improvements (#6931)

We improve some of the coding in the debugging area to make the logic
easier to follow and to remove some unnecessary complexity.

## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [ ] Title is accurate.
- [ ] No unnecessary changes are introduced.
- [ ] Description motivates each change.
- [ ] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [ ] Testing strategy adequately addresses listed risk(s).
- [ ] Change is maintainable (easy to change, telemetry, documentation).
- [ ] Release note makes sense to a user of the library.
- [ ] Reviewer has explicitly acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment.
- [ ] Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)
- [ ] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [ ] This PR doesn't touch any of that.

Author: P403n1x87

ddtrace/debugging/_debugger.py

@@ -489,6 +489,9 @@ def _inject_probes(self, probes):
         # type: (List[LineProbe]) -> None
         for probe in probes:
             if probe not in self._probe_registry:
+                if len(self._probe_registry) >= di_config.max_probes:
+                    log.warning("Too many active probes. Ignoring new ones.")
+                    return
                 log.debug("[%s][P: %s] Received new %s.", os.getpid(), os.getppid(), probe)
                 self._probe_registry.register(probe)
 
@@ -609,6 +612,10 @@ def _probe_wrapping_hook(self, module):
     def _wrap_functions(self, probes):
         # type: (List[FunctionProbe]) -> None
         for probe in probes:
+            if len(self._probe_registry) >= di_config.max_probes:
+                log.warning("Too many active probes. Ignoring new ones.")
+                return
+
             self._probe_registry.register(probe)
             try:
                 assert probe.module is not None  # nosec
@@ -662,9 +669,6 @@ def _unwrap_functions(self, probes):
     def _on_configuration(self, event, probes):
         # type: (ProbePollerEventType, Iterable[Probe]) -> None
         log.debug("[%s][P: %s] Received poller event %r with probes %r", os.getpid(), os.getppid(), event, probes)
-        if len(list(probes)) + len(self._probe_registry) > di_config.max_probes:
-            log.warning("Too many active probes. Ignoring new ones.")
-            return
 
         if event == ProbePollerEvent.STATUS_UPDATE:
             self._probe_registry.log_probes_status()

ddtrace/debugging/_probe/remoteconfig.py

@@ -328,27 +328,30 @@ def _exec_callback(self, data, test_tracer=None):
             self._send_status_update()
             self._status_timestamp = next(self._status_timestamp_sequence)
 
-        if data:
-            metadatas = data["metadata"]
-            rc_configs = data["config"]
-            # DEV: We emit a status update event here to avoid having to spawn a
-            # separate thread for this.
-            log.debug("[%s][P: %s] Dynamic Instrumentation Updated", os.getpid(), os.getppid())
-            for idx in range(len(rc_configs)):
-                if metadatas[idx] is None:
-                    log.debug("[%s][P: %s] Dynamic Instrumentation, no RCM metadata", os.getpid(), os.getppid())
-                    return
-
-                self._update_probes_for_config(metadatas[idx]["id"], rc_configs[idx])
+        if not data:
+            # Nothing else to do.
+            return
+
+        log.debug("[%s][P: %s] Dynamic Instrumentation Updated", os.getpid(), os.getppid())
+        for metadata, config in zip(data["metadata"], data["config"]):
+            if metadata is None:
+                log.debug(
+                    "[%s][P: %s] Dynamic Instrumentation: no RCM metadata for configuration; skipping",
+                    os.getpid(),
+                    os.getppid(),
+                )
+                continue
+
+            self._update_probes_for_config(metadata["id"], config)
 
     def _send_status_update(self):
         log.debug(
-            "[%s][P: %s] Dynamic Instrumentation,Emitting probe status log messages",
+            "[%s][P: %s] Dynamic Instrumentation: emitting probe status log messages",
             os.getpid(),
             os.getppid(),
         )
-        probes = [probe for config in self._configs.values() for probe in config.values()]
-        self._callback(ProbePollerEvent.STATUS_UPDATE, probes)
+
+        self._callback(ProbePollerEvent.STATUS_UPDATE, [])
 
     def _dispatch_probe_events(self, prev_probes, next_probes):
         # type: (Dict[str, Probe], Dict[str, Probe]) -> None

tests/debugging/exception/test_auto_instrument.py

@@ -121,7 +121,6 @@ def c(foo=42):
             assert len(d.test_queue) == 3
 
             snapshots = {str(s.uuid): s for s in d.test_queue}
-            print(snapshots.keys())
 
             if PY < (3, 0):
                 stacks = [["c", "b_chain"], ["b_chain"], ["a"]]
@@ -137,8 +136,6 @@ def c(foo=42):
 
                 info = {k: v for k, v in enumerate(stacks[n], start=1)}
 
-                print(span._meta["error.stack"], info)
-
                 for i in range(1, len(info) + 1):
                     fn = info[i]
 

tests/debugging/probe/test_remoteconfig.py

@@ -339,7 +339,7 @@ def callback(e, ps, *args, **kwargs):
             (ProbePollerEvent.NEW_PROBES, frozenset(["probe4", "probe1", "probe2", "probe3"])),
             (ProbePollerEvent.DELETED_PROBES, frozenset(["probe1"])),
             (ProbePollerEvent.NEW_PROBES, frozenset(["probe5"])),
-            (ProbePollerEvent.STATUS_UPDATE, frozenset(["probe4", "probe2", "probe3", "probe5"])),
+            (ProbePollerEvent.STATUS_UPDATE, frozenset()),
         }, events
     finally:
         di_config.diagnostics_interval = old_interval
@@ -427,7 +427,7 @@ def cb(e, ps):
             (ProbePollerEvent.NEW_PROBES, frozenset({"probe1"})),
             (ProbePollerEvent.NEW_PROBES, frozenset({"probe2"})),
             (ProbePollerEvent.NEW_PROBES, frozenset({"probe3"})),
-            (ProbePollerEvent.STATUS_UPDATE, frozenset({"probe1", "probe2", "probe3"})),
+            (ProbePollerEvent.STATUS_UPDATE, frozenset()),
         }
 
         # remove configuration
@@ -438,7 +438,7 @@ def cb(e, ps):
             (ProbePollerEvent.NEW_PROBES, frozenset({"probe1"})),
             (ProbePollerEvent.NEW_PROBES, frozenset({"probe2"})),
             (ProbePollerEvent.NEW_PROBES, frozenset({"probe3"})),
-            (ProbePollerEvent.STATUS_UPDATE, frozenset({"probe1", "probe2", "probe3"})),
+            (ProbePollerEvent.STATUS_UPDATE, frozenset()),
             (ProbePollerEvent.DELETED_PROBES, frozenset({"probe2"})),
         }
 
@@ -579,7 +579,7 @@ def cb(e, ps):
             (ProbePollerEvent.STATUS_UPDATE, frozenset()),
             (ProbePollerEvent.NEW_PROBES, frozenset(["probe1"])),
             (ProbePollerEvent.MODIFIED_PROBES, frozenset(["probe1"])),
-            (ProbePollerEvent.STATUS_UPDATE, frozenset(["probe1"])),
+            (ProbePollerEvent.STATUS_UPDATE, frozenset()),
         ]
     finally:
         di_config.diagnostics_interval = old_interval