[celery] minor changes by palazzem · Pull Request #196 · DataDog/dd-trace-py

palazzem · 2017-02-23T13:05:09Z

What it does

Related to #135. It's only a minor set of changes related to documentation and how the application is instrumented. Adds some tests using functions with arguments so that we're sure arguments are properly passed.

palazzem · 2017-02-23T13:07:17Z

@@ -1,14 +1,11 @@
 """
-Supported versions:


we can add these somewhere in the docs; we have to do this for all current instrumentation (will take care in a separated PR)

palazzem · 2017-02-23T13:08:45Z

 @require_pin
 def _task_apply(pin, func, task, args, kwargs):
-    with pin.tracer.trace(TASK_APPLY, resource=task.name) as span:
+    with pin.tracer.trace(TASK_APPLY, service=pin.service, resource=task.name) as span:


Usually the apply() is called by primary services (i.e. Django or Flask). If we omit this, it means that it would be part of the Django / Flask service. Not sure if it's OK because we may have an exception with the broker / job creation that would be considered a Django / Flask fail.

Also if for some reason this is the root span, the trace could be discarded because no services are defined.

👍 makes sense

palazzem · 2017-02-23T13:09:35Z

 # Default set of modules to automatically patch or not
 PATCH_MODULES = {
    'cassandra': True,
+    'celery': True,


we have to decide if we want to auto instrument Celery when we patch_all()

brettlangdon · 2017-02-23T13:11:15Z

@palazzem these changes look good to me 👍

palazzem · 2017-02-23T13:11:32Z

        setattr(app, method_name, wrapt.FunctionWrapper(method, wrapper))

+    # patch the Task class if available
+    setattr(app, 'Task', patch_task(app.Task))


when we patch the app, we may consider to patch also the Task otherwise https://github.com/DataDog/dd-trace-py/pull/196/files#diff-10c6d560aac930440a75c594cd2583a7R169 will fail.

LotharSee · 2017-02-23T17:54:16Z

+        for x in range(100):
+            fn_task.delay()
+
+        traces = self.tracer.writer.pop_traces()


Is there a risk that we didn't finish all the tasks by the moment we arrive here? (I don't know celery internals, even if the task is trivial, can they be queued for later?)

So with this patching we trace two parts of celery, the code which schedules a task to be executed and the execution of the task.

In this test we are using .delay() which is a task scheduler, so the function will block until the task is pushed into our broker. It won't wait until the task has completed, and that is totally fine/expected.

Actually tasks are not executed, unless we're running a real worker / using the Celery threaded workers (available only on Celery 4.0+). All delay() calls return immediately and tasks are enqueued for later processing.

Because of that, we generally have 2 spans for each execution (one for the enqueuing and one for the execution), but this is the expected behavior.

LotharSee · 2017-02-23T17:59:09Z

+            'custom_meta': 'custom_value',
+        }
+
+        metas = meta_from_context(context)


meta keys should be prefixed with celery.?

Fixed here: https://github.com/DataDog/dd-trace-py/pull/196/files#diff-bddee7faa15a5040f3021b7a38e28302R33

LotharSee · 2017-02-23T18:02:35Z

@@ -1,14 +1,11 @@
 """
-Supported versions:


Is there a celery section in the doc?

nice catch! :)

Fixed here: https://github.com/DataDog/dd-trace-py/pull/196/files#diff-caf2a6b8f4947d018f68893c695b5202R173

…llocator (#17664) ## Description This PR fixes a segmentation fault in the memory allocation profiler that occurs when a hook call races with `memalloc` start/stop operations. The issue arises from concurrent access to the saved allocator struct, which could be partially written while being read, resulting in`NULL` function pointers being dereferenced. The key indicator in that case is that `#1 0x0000000000000000` frame -- we are trying to execute a null function pointer. ```` Error UnixSignal: Process terminated with SEGV_MAPERR (SIGSEGV) #0 0x00007ff3c303a8d4 #1 0x0000000000000000 memalloc_alloc (/go/src/github.com/DataDog/apm-reliability/dd-trace-py/ddtrace/profiling/collector/_memalloc.cpp:68) #2 0x00007ff39dcb3b20 memalloc_alloc (/go/src/github.com/DataDog/apm-reliability/dd-trace-py/ddtrace/profiling/collector/_memalloc.cpp:68) #3 0x00007ff39dcb3b20 memalloc_malloc(void*, unsigned long) (/go/src/github.com/DataDog/apm-reliability/dd-trace-py/ddtrace/profiling/collector/_memalloc.cpp:80) #4 0x00007ff3c3087e1b PyUnicode_New #5 0x00007ff3c30889f4 #6 0x00007ff3c3170c84 #7 0x00007ff3c316b931 #8 0x00007ff3c31aaac8 #9 0x00007ff3c31033ac #10 0x00007ff3c310e2a6 PyObject_CallMethodObjArgs #11 0x00007ff3c310e46d #12 0x00007ff3c31a96c2 #13 0x00007ff3c3102fd7 PyObject_Vectorcall #14 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #15 0x00007ff3c323c094 #16 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #17 0x00007ff3c323c094 #18 0x00007ff3c30e997d PyObject_CallOneArg #19 0x00007ff3c306a480 _PyObject_GenericGetAttrWithDict #20 0x00007ff3c30c620d PyObject_GetAttr #21 0x00007ff3c32309e7 _PyEval_EvalFrameDefault #22 0x00007ff3c323c094 #23 0x00007ff3c312880e #24 0x00007ff3c30e917c _PyObject_MakeTpCall #25 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #26 0x00007ff3c323c094 #27 0x00007ff3c312880e #28 0x00007ff3c30e917c _PyObject_MakeTpCall #29 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #30 0x00007ff3c323c094 #31 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #32 0x00007ff3c323c094 #33 0x00007ff3c317d0fd #34 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #35 0x00007ff3c323c094 #36 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #37 0x00007ff3c323c094 #38 0x00007ff3c317d1b5 #39 0x00007ff3c3102fd7 PyObject_Vectorcall #40 0x00007ff3c3232f4a _PyEval_EvalFrameDefault #41 0x00007ff3c3240da5 #42 0x00007ff3c324112d #43 0x00007ff3c3233be1 _PyEval_EvalFrameDefault #44 0x00007ff3c323c094 #45 0x00007ff3c317d1b5 #46 0x00007ff3c3102fd7 PyObject_Vectorcall #47 0x00007ff3c3232f4a _PyEval_EvalFrameDefault #48 0x00007ff3c323c094 #49 0x00007ff3c31033ac #50 0x00007ff3c310358d PyObject_CallFunctionObjArgs #51 0x00007ff3bf7eb91d WraptBoundFunctionWrapper_call (/project/src/wrapt/_wrappers.c:3750) #52 0x00007ff3c3104055 _PyObject_Call #53 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #54 0x00007ff3c323c094 #55 0x00007ff3c317d23c #56 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #57 0x00007ff3c323c094 #58 0x00007ff3c310416f _PyObject_Call #59 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #60 0x00007ff3c3240da5 #61 0x00007ff3c324112d #62 0x00007ff3c3233be1 _PyEval_EvalFrameDefault #63 0x00007ff3c323c094 #64 0x00007ff3c317d1b5 #65 0x00007ff3c3102fd7 PyObject_Vectorcall #66 0x00007ff3c3232f4a _PyEval_EvalFrameDefault #67 0x00007ff3c323c094 #68 0x00007ff3c317d1b5 #69 0x00007ff3c310416f _PyObject_Call #70 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #71 0x00007ff3c323c094 #72 0x00007ff3c317d1b5 #73 0x00007ff3c310416f _PyObject_Call #74 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #75 0x00007ff3c323c094 #76 0x00007ff3c31033ac #77 0x00007ff3c310358d PyObject_CallFunctionObjArgs #78 0x00007ff3bf7eb91d WraptBoundFunctionWrapper_call (/project/src/wrapt/_wrappers.c:3750) #79 0x00007ff3c30e917c _PyObject_MakeTpCall #80 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #81 0x00007ff3c323c094 #82 0x00007ff3c317d518 #83 0x00007ff3c3155963 #84 0x00007ff3c315393d #85 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #86 0x00007ff3c323c094 #87 0x00007ff3c317d0fd #88 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #89 0x00007ff3c323c094 #90 0x00007ff3c317d0fd #91 0x00007ff3c317d518 #92 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #93 0x00007ff3c323c094 #94 0x00007ff3c30e9371 _PyObject_FastCallDictTstate #95 0x00007ff3c30e958d _PyObject_Call_Prepend #96 0x00007ff3c3109150 #97 0x00007ff3c3104055 _PyObject_Call #98 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #99 0x00007ff3c323c094 #100 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #101 0x00007ff3c30e958d _PyObject_Call_Prepend #102 0x00007ff3c3109150 #103 0x00007ff3c30e917c _PyObject_MakeTpCall #104 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #105 0x00007ff3c323c094 #106 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #107 0x00007ff3c30e958d _PyObject_Call_Prepend #108 0x00007ff3c3109150 #109 0x00007ff3c30e917c _PyObject_MakeTpCall #110 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #111 0x00007ff3c323c094 #112 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #113 0x00007ff3c30e958d _PyObject_Call_Prepend #114 0x00007ff3c3109150 #115 0x00007ff3c30e917c _PyObject_MakeTpCall #116 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #117 0x00007ff3c323c094 #118 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #119 0x00007ff3c30e958d _PyObject_Call_Prepend #120 0x00007ff3c3109150 #121 0x00007ff3c30e917c _PyObject_MakeTpCall #122 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #123 0x00007ff3c323c094 #124 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #125 0x00007ff3c30e958d _PyObject_Call_Prepend #126 0x00007ff3c3109150 #127 0x00007ff3c30e917c _PyObject_MakeTpCall #128 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #129 0x00007ff3c323c094 #130 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #131 0x00007ff3c30e958d _PyObject_Call_Prepend #132 0x00007ff3c3109150 #133 0x00007ff3c30e917c _PyObject_MakeTpCall #134 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #135 0x00007ff3c323c094 #136 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #137 0x00007ff3c30e958d _PyObject_Call_Prepend #138 0x00007ff3c3109150 #139 0x00007ff3c30e917c _PyObject_MakeTpCall #140 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #141 0x00007ff3c323c094 #142 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #143 0x00007ff3c30e958d _PyObject_Call_Prepend #144 0x00007ff3c3109150 #145 0x00007ff3c30e917c _PyObject_MakeTpCall #146 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #147 0x00007ff3c323c094 #148 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #149 0x00007ff3c30e958d _PyObject_Call_Prepend #150 0x00007ff3c3109150 #151 0x00007ff3c30e917c _PyObject_MakeTpCall #152 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #153 0x00007ff3c323c094 #154 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #155 0x00007ff3c30e958d _PyObject_Call_Prepend #156 0x00007ff3c3109150 #157 0x00007ff3c30e917c _PyObject_MakeTpCall #158 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #159 0x00007ff3c323c094 #160 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #161 0x00007ff3c30e958d _PyObject_Call_Prepend #162 0x00007ff3c3109150 #163 0x00007ff3c30e917c _PyObject_MakeTpCall #164 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #165 0x00007ff3c323c094 #166 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #167 0x00007ff3c30e958d _PyObject_Call_Prepend #168 0x00007ff3c3109150 #169 0x00007ff3c30e917c _PyObject_MakeTpCall #170 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #171 0x00007ff3c323c094 #172 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #173 0x00007ff3c30e958d _PyObject_Call_Prepend #174 0x00007ff3c3109150 #175 0x00007ff3c30e917c _PyObject_MakeTpCall #176 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #177 0x00007ff3c323c094 #178 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #179 0x00007ff3c30e958d _PyObject_Call_Prepend #180 0x00007ff3c3109150 #181 0x00007ff3c30e917c _PyObject_MakeTpCall #182 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #183 0x00007ff3c323c094 #184 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #185 0x00007ff3c30e958d _PyObject_Call_Prepend #186 0x00007ff3c3109150 #187 0x00007ff3c30e917c _PyObject_MakeTpCall #188 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #189 0x00007ff3c323c094 #190 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #191 0x00007ff3c323c094 #192 0x00007ff3c30e92f1 _PyObject_FastCallDictTstate #193 0x00007ff3c30e958d _PyObject_Call_Prepend #194 0x00007ff3c3109150 #195 0x00007ff3c30e917c _PyObject_MakeTpCall #196 0x00007ff3c32335a2 _PyEval_EvalFrameDefault #197 0x00007ff3c323c094 #198 0x00007ff3c317d0fd #199 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #200 0x00007ff3c323c094 #201 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #202 0x00007ff3c323c094 #203 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #204 0x00007ff3c323c094 #205 0x00007ff3c3233dd3 _PyEval_EvalFrameDefault #206 0x00007ff3c323c094 #207 0x00007ff3c317d23c #208 0x00007ff3c31a7ec5 #209 0x00007ff3c301ac77 #210 0x00007ff3c357c573 ```` The fix implements two key changes. 1. **Hook functions (`memalloc_alloc`, `memalloc_realloc`)**: Snapshot the allocator struct locally before use and guard indirect function calls with `NULL` checks. This prevents crashes if a partially-written struct is observed during a start/stop race. 2. **Start/stop operations (`memalloc_start`, `memalloc_stop`)**: Use local variables and single assignments when publishing the allocator struct to `global_memalloc_ctx.pymem_allocator_obj`. This ensures concurrent hook calls observe either the old or new struct, never a partially-written intermediate state. The real root cause is that `PyMem_GetAllocator` is not documented as atomic, and the struct could be read field-by-field while being written to concurrently. By using local copies and single assignments, we ensure atomicity at the C level and prevent observation of inconsistent state. Co-authored-by: thomas.kowalski <thomas.kowalski@datadoghq.com>

Emanuele Palazzetti added 8 commits February 23, 2017 14:01

[tests] backporting tracing counter

2748566

[celery] add docs upon changes

f73a82b

[celery] when patching an app, patch also the Task class

550c4ab

[celery] all celery spans belong to celery service

5c97692

[celery] patch_all will patch Celery automatically

78d29b8

[celery] add integration tests to ensure signature compatibility

c8bc92c

[celery] "timelimit" typo prevents the drop if it was None

8572edb

[celery] cosmetics and flake

08ca144

palazzem added the integrations label Feb 23, 2017

palazzem requested a review from LotharSee February 23, 2017 13:05

palazzem mentioned this pull request Feb 23, 2017

celery: add celery app and task patching #135

Merged

palazzem commented Feb 23, 2017

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[celery] missing comments on tests

b8deac7

palazzem added this to the 0.6.0 milestone Feb 23, 2017

palazzem assigned LotharSee Feb 23, 2017

LotharSee reviewed Feb 23, 2017

View reviewed changes

Emanuele Palazzetti added 2 commits February 24, 2017 10:36

[celery] add celery docs

9d8f093

[celery] tags are prefixed with "celery"

49dce09

LeoCavaille approved these changes Feb 24, 2017

View reviewed changes

LotharSee approved these changes Feb 24, 2017

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palazzem merged commit 002f869 into master Feb 24, 2017

palazzem deleted the palazzem/celery-minor-changes branch February 24, 2017 10:50

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palazzem commented Feb 23, 2017 •

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