Improving current documentation by palazzem · Pull Request #194 · DataDog/dd-trace-py

palazzem · 2017-02-21T16:54:23Z

What it does

Docs for start_span method
Overall improvements
API section moved at the bottom of the doc
Created the Advanced usage section

clutchski · 2017-02-21T17:41:30Z

+~~~~~~~~~~~~~~~~~~

-Then let's patch all the widely used Python libraries that you are running::
+Then let's patch all used Python libraries that you are running through::


this doesn't really make sense:

Then let's patch widely used Python libraries::

clutchski · 2017-02-21T17:41:45Z


 .. automodule:: ddtrace.contrib.sqlite3

+Asynchronous libraries


Async Libraries

Will apply the same rule everywhere 👍

clutchski · 2017-02-21T18:01:35Z


-Databases
-~~~~~~~~~
+Instrument modules


I don't love this title since everything is a library. Maybe just leave it at databases?

Yea, the idea is because we're patch[ing] widely used Python libraries, I thought it was not only related to Databases. But yea, can rollback the change.

LeoCavaille

LGTM, just some small nitpicks.

LeoCavaille · 2017-02-23T13:54:26Z

+                # do something
+
+        Trace will store the current active span and subsequent child traces will
+        become it's children::


it's -> its

LeoCavaille · 2017-02-23T13:54:40Z

        """
-        Return the current active span in this call Context or None.
+        Return the active span for the current call context or ``None``
+        if not spans are available.


if no spans

LeoCavaille · 2017-02-23T13:56:20Z


 .. automodule:: ddtrace.contrib.pyramid

+Aiohttp


nitpick but I don't think those should be capitalized if the project names are always displayed lower case "aiohttp", "gevent" ...

LeoCavaille · 2017-02-23T13:58:18Z

+
+A particular query to a service. For a web application, some
+examples might be a URL stem like :code:`/user/home` or a handler function
+like :code:`web.user.home`. For a sql database, a resource


nit: sql -> SQL

LeoCavaille · 2017-02-23T13:59:36Z

+
+A span tracks a unit of work in a service, like querying a database or
+rendering a template. Spans are associated with a service and optionally a
+resource. Spans have names, start times, durations and optional tags.


I'd prefer using a singular sentence for more clarity:

A span has a name, start time, duration and optional tags.

…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 3 commits February 21, 2017 17:37

[docs] updated Tracer API documentation

46fb5d4

[docs] created Advanced Usage section

4242596

[docs] add aiohttp, asyncio and gevent documentation

48e8bcc

palazzem added the docs label Feb 21, 2017

palazzem requested review from awang and clutchski February 21, 2017 16:54

palazzem mentioned this pull request Feb 21, 2017

add asynchronous support for the current Tracer #161

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6 tasks

clutchski reviewed Feb 21, 2017

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[docs] minor changes

a5fdf80

palazzem assigned LotharSee Feb 22, 2017

palazzem added this to the 0.6.0 milestone Feb 22, 2017

LotharSee approved these changes Feb 22, 2017

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LeoCavaille approved these changes Feb 23, 2017

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[docs] typo and minor changes

94b2644

LotharSee approved these changes Feb 23, 2017

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palazzem merged commit 672c6d6 into palazzem/async-python Mar 1, 2017

palazzem deleted the palazzem/async-docs branch March 1, 2017 10:33


		.. automodule:: ddtrace.contrib.sqlite3

		Asynchronous libraries

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palazzem commented Feb 21, 2017

What it does

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