mirror of https://github.com/asterisk/asterisk
What's wrong with ast_debug?
ast_debug is fine for general purpose debug output but it's not
really geared for scope tracing since it doesn't present its
output in a way that makes capturing and analyzing flow through
Asterisk easy.
How is scope tracing better?
Scope tracing uses the same "cleanup" attribute that RAII_VAR
uses to print messages to a separate "trace" log level. Even
better, the messages are indented and unindented based on a
thread-local call depth counter. When output to a separate log
file, the output is uncluttered and easy to follow.
Here's an example of the output. The leading timestamps and
thread ids are removed and the output cut off at 68 columns for
commit message restrictions but you get the idea.
--> res_pjsip_session.c:3680 handle_incoming PJSIP/1173-00000001
--> res_pjsip_session.c:3661 handle_incoming_response PJSIP/1173
--> res_pjsip_session.c:3669 handle_incoming_response PJSIP/
--> chan_pjsip.c:3265 chan_pjsip_incoming_response_after
--> chan_pjsip.c:3194 chan_pjsip_incoming_response P
chan_pjsip.c:3245 chan_pjsip_incoming_respon
<-- chan_pjsip.c:3194 chan_pjsip_incoming_response P
<-- chan_pjsip.c:3265 chan_pjsip_incoming_response_after
<-- res_pjsip_session.c:3669 handle_incoming_response PJSIP/
<-- res_pjsip_session.c:3661 handle_incoming_response PJSIP/1173
<-- res_pjsip_session.c:3680 handle_incoming PJSIP/1173-00000001
The messages with the "-->" or "<--" were produced by including
the following at the top of each function:
SCOPE_TRACE(1, "%s\n", ast_sip_session_get_name(session));
Scope isn't limited to functions any more than RAII_VAR is. You
can also see entry and exit from "if", "for", "while", etc blocks.
There is also an ast_trace() macro that doesn't track entry or
exit but simply outputs a message to the trace log using the
current indent level. The deepest message in the sample
(chan_pjsip.c:3245) was used to indicate which "case" in a
"select" was executed.
How do you use it?
More documentation is available in logger.h but here's an overview:
* Configure with --enable-dev-mode. Like debug, scope tracing
is #ifdef'd out if devmode isn't enabled.
* Add a SCOPE_TRACE() call to the top of your function.
* Set a logger channel in logger.conf to output the "trace" level.
* Use the CLI (or cli.conf) to set a trace level similar to setting
debug level... CLI> core set trace 2 res_pjsip.so
Summary Of Changes:
* Added LOG_TRACE logger level. Actually it occupies the slot
formerly occupied by the now defunct "event" level.
* Added core asterisk option "trace" similar to debug. Includes
ability to specify global trace level in asterisk.conf and CLI
commands to turn on/off and set levels. Levels can be set
globally (probably not a good idea), or by module/source file.
* Updated sample asterisk.conf and logger.conf. Tracing is
disabled by default in both.
* Added __ast_trace() to logger.c which keeps track of the indent
level using TLS. It's #ifdef'd out if devmode isn't enabled.
* Added ast_trace() and SCOPE_TRACE() macros to logger.h.
These are all #ifdef'd out if devmode isn't enabled.
Why not use gcc's -finstrument-functions capability?
gcc's facility doesn't allow access to local data and doesn't
operate on non-function scopes.
Known Issues:
The only know issue is that we currently don't know the line
number where the scope exited. It's reported as the same place
the scope was entered. There's probably a way to get around it
but it might involve looking at the stack and doing an 'addr2line'
to get the line number. Kind of like ast_backtrace() does.
Not sure if it's worth it.
Change-Id: Ic5ebb859883f9c10a08c5630802de33500cad027
pull/20/head
George Joseph
5 years ago
committed by
Friendly Automation
parent
c16937cdbe
commit
ca3c22c5f1
@ -0,0 +1,107 @@
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/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2020, Sangoma Technologies Corp
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*
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* George Joseph <gjoseph@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*!
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* \file
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* \brief Test for Scope Trace
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*
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* \author\verbatim George Joseph <gjoseph@digium.com> \endverbatim
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*
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* tests for Scope Trace
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* \ingroup tests
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*/
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/*** MODULEINFO
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<depend>TEST_FRAMEWORK</depend>
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<support_level>core</support_level>
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***/
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#include "asterisk.h"
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#include "asterisk/utils.h"
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#include "asterisk/module.h"
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#include "asterisk/test.h"
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#include "asterisk/logger.h"
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static void test_scope2(void)
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{
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SCOPE_TRACE(1);
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}
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static void test_scope(void)
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{
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SCOPE_TRACE(1, "nested function: %d * %d = %d\n", 6, 7, (6 * 7));
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test_scope2();
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ast_trace(1, "test no variables\n");
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}
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AST_TEST_DEFINE(scope_test)
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{
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SCOPE_TRACE(1, "top %s function\n", "scope_test");
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ast_trace(1, "%s\n", "test outer");
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switch (cmd) {
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case TEST_INIT:
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info->name = "scope_test";
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info->category = "/main/logging/";
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info->summary = "Scope Trace Tests";
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info->description = "Scope Trace Tests";
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return AST_TEST_NOT_RUN;
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case TEST_EXECUTE:
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{
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SCOPE_TRACE(1, "CASE statement\n");
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ast_trace(1, "%s\n", "test case");
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}
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break;
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}
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if (1) {
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SCOPE_TRACE(1, "IF block\n");
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test_scope();
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}
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ast_trace(1);
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ast_trace(1, "test no variables\n");
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ast_trace(1, "%s\n", "test variable");
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return AST_TEST_PASS;
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}
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static int unload_module(void)
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{
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AST_TEST_UNREGISTER(scope_test);
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return 0;
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}
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static int load_module(void)
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{
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AST_TEST_REGISTER(scope_test);
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return AST_MODULE_LOAD_SUCCESS;
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}
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AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Scope Trace Test");
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