luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2025-03-10 09:49:19 +01:00
Code Issues Packages Projects Releases Wiki Activity

gmessages: Treat DEBUG_INVOCATION=1 same as G_MESSAGES_DEBUG=all

Browse Source 
systemd 257 will now set `DEBUG_INVOCATION=1` in the execution context
of services which need to be debugged — for example if they’ve failed
and been restarted (and `RestartMode=debug`).

If we handle `DEBUG_INVOCATION=1` as being equivalent to
`G_MESSAGES_DEBUG=all`, then any processes using GLib’s default log
writer function (or `g_log_writer_default_would_drop()`) automatically
gains support for this feature.

See https://mastodon.social/@pid_eins/113548825942383777

Signed-off-by: Philip Withnall <pwithnall@gnome.org>
This commit is contained in:
Philip Withnall 2024-11-26 15:38:41 +00:00
parent dfe252429c
commit 8b29c53057
No known key found for this signature in database
GPG Key ID: C5C42CFB268637CA
3 changed files with 40 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
docs/reference/glib/logging.md
View File

@ -92,13 +92,14 @@ The default log functions (`g_log_default_handler()` for the old-style API
and `g_log_writer_default()` for the structured API) both drop debug and
informational messages by default, unless the log domains of those messages
are listed in the `G_MESSAGES_DEBUG` environment variable (or it is set to
`all`).
`all`), or `DEBUG_INVOCATION=1` is set in the environment.
It is recommended that custom log writer functions re-use the
`G_MESSAGES_DEBUG` environment variable, rather than inventing a custom one,
so that developers can re-use the same debugging techniques and tools across
projects. Since GLib 2.68, this can be implemented by dropping messages for
which `g_log_writer_default_would_drop()` returns `TRUE`.
`G_MESSAGES_DEBUG` and `DEBUG_INVOCATION` environment variables, rather than
inventing a custom one, so that developers can re-use the same debugging
techniques and tools across projects. Since GLib 2.68, this can be implemented
by dropping messages for which `g_log_writer_default_would_drop()` returns
`TRUE`.
## Testing for Messages

32
glib/gmessages.c
View File

@ -316,8 +316,9 @@
* manually.
*
* Such messages are suppressed by the [func@GLib.log_default_handler] and
* [func@GLib.log_writer_default] unless the `G_MESSAGES_DEBUG` environment variable is
* set appropriately. If you need to set the allowed domains at runtime, use
* [func@GLib.log_writer_default] unless the `G_MESSAGES_DEBUG` or
* `DEBUG_INVOCATION` environment variables are set appropriately. If you need
* to set the allowed domains at runtime, use
* [func@GLib.log_writer_default_set_debug_domains].
*
* If structured logging is enabled, this will use [func@GLib.log_structured];
@ -341,8 +342,9 @@
* manually.
*
* Such messages are suppressed by the [func@GLib.log_default_handler] and
* [func@GLib.log_writer_default] unless the `G_MESSAGES_DEBUG` environment variable is
* set appropriately. If you need to set the allowed domains at runtime, use
* [func@GLib.log_writer_default] unless the `G_MESSAGES_DEBUG` or
* `DEBUG_INVOCATION` environment variables are set appropriately. If you need
* to set the allowed domains at runtime, use
* [func@GLib.log_writer_default_set_debug_domains].
*
* If structured logging is enabled, this will use [func@GLib.log_structured];
@ -2705,7 +2707,7 @@ static struct {
* `NULL` or an array with no values means none. Array with a single value `"all"` means all.
*
* Reset the list of domains to be logged, that might be initially set by the
* `G_MESSAGES_DEBUG` environment variable.
* `G_MESSAGES_DEBUG` or `DEBUG_INVOCATION` environment variables.
*
* This function is thread-safe.
*
@ -2737,7 +2739,7 @@ should_drop_message (GLogLevelFlags log_level,
const GLogField *fields,
gsize n_fields)
{
/* Disable debug message output unless specified in G_MESSAGES_DEBUG. */
/* Disable debug message output unless specified in G_MESSAGES_DEBUG/DEBUG_INVOCATION. */
if (!(log_level & DEFAULT_LEVELS) &&
!(log_level >> G_LOG_LEVEL_USER_SHIFT) &&
!g_log_get_debug_enabled ())
@ -2750,6 +2752,8 @@ should_drop_message (GLogLevelFlags log_level,
if (G_UNLIKELY (!g_log_global.domains_set))
{
g_log_global.domains = g_strdup (g_getenv ("G_MESSAGES_DEBUG"));
if (g_log_global.domains == NULL && g_strcmp0 (g_getenv ("DEBUG_INVOCATION"), "1") == 0)
g_log_global.domains = g_strdup ("all");
g_log_global.domains_set = TRUE;
}
@ -2804,7 +2808,8 @@ should_drop_message (GLogLevelFlags log_level,
*
* As with [func@GLib.log_default_handler], this function drops debug and informational
* messages unless their log domain (or `all`) is listed in the space-separated
* `G_MESSAGES_DEBUG` environment variable, or by [func@GLib.log_writer_default_set_debug_domains].
* `G_MESSAGES_DEBUG` environment variable, or `DEBUG_INVOCATION=1` is set in
* the environment, or by [func@GLib.log_writer_default_set_debug_domains].
*
* This can be used when implementing log writers with the same filtering
* behaviour as the default, but a different destination or output format:
@ -2815,7 +2820,7 @@ should_drop_message (GLogLevelFlags log_level,
* ]|
*
* or to skip an expensive computation if it is only needed for a debugging
* message, and `G_MESSAGES_DEBUG` is not set:
* message, and `G_MESSAGES_DEBUG` and `DEBUG_INVOCATION` are not set:
*
* ```c
* if (!g_log_writer_default_would_drop (G_LOG_LEVEL_DEBUG, G_LOG_DOMAIN))
@ -2862,7 +2867,8 @@ g_log_writer_default_would_drop (GLogLevelFlags log_level,
*
* As with [func@GLib.log_default_handler], this function drops debug and informational
* messages unless their log domain (or `all`) is listed in the space-separated
* `G_MESSAGES_DEBUG` environment variable, or set at runtime by [func@GLib.log_writer_default_set_debug_domains].
* `G_MESSAGES_DEBUG` environment variable, or `DEBUG_INVOCATION=1` is set in
* the environment, or set at runtime by [func@GLib.log_writer_default_set_debug_domains].
*
* [func@GLib.log_writer_default] uses the mask set by [func@GLib.log_set_always_fatal] to
* determine which messages are fatal. When using a custom writer function instead it is
@ -3005,7 +3011,8 @@ _g_log_writer_fallback (GLogLevelFlags log_level,
* implementations.
*
* Note also that the value of this does not depend on `G_MESSAGES_DEBUG`, nor
* [func@GLib.log_writer_default_set_debug_domains]; see the docs for [func@GLib.log_set_debug_enabled].
* `DEBUG_INVOCATION`, nor [func@GLib.log_writer_default_set_debug_domains]; see
* the docs for [func@GLib.log_set_debug_enabled].
*
* Returns: `TRUE` if debug output is enabled, `FALSE` otherwise
*
@ -3023,7 +3030,7 @@ g_log_get_debug_enabled (void)
*
* Enable or disable debug output from the GLib logging system for all domains.
*
* This value interacts disjunctively with `G_MESSAGES_DEBUG` and
* This value interacts disjunctively with `G_MESSAGES_DEBUG`, `DEBUG_INVOCATION` and
* [func@GLib.log_writer_default_set_debug_domains] — if any of them would allow
* a debug message to be outputted, it will be.
*
@ -3355,6 +3362,9 @@ escape_string (GString *string)
* which debug and informational messages are printed. By default
* these messages are not printed. If you need to set the allowed
* domains at runtime, use [func@GLib.log_writer_default_set_debug_domains].
* - `DEBUG_INVOCATION`: If set to `1`, this is equivalent to
* `G_MESSAGES_DEBUG=all`. `DEBUG_INVOCATION` is a standard environment
* variable set by systemd to prompt debug output. (Since: 2.84)
*
* `stderr` is used for levels [flags@GLib.LogLevelFlags.LEVEL_ERROR],
* [flags@GLib.LogLevelFlags.LEVEL_CRITICAL], [flags@GLib.LogLevelFlags.LEVEL_WARNING] and

13
glib/tests/logging.c
View File

@ -201,6 +201,15 @@ test_default_handler_debug_stderr (void)
exit (0);
}
static void
test_default_handler_would_drop_env_systemd (void)
{
g_setenv ("DEBUG_INVOCATION", "1", TRUE);
g_assert_false (g_log_writer_default_would_drop (G_LOG_LEVEL_DEBUG, "foo"));
g_assert_false (g_log_writer_default_would_drop (G_LOG_LEVEL_DEBUG, "bar"));
}
static void
test_default_handler_would_drop_env5 (void)
{
@ -558,6 +567,9 @@ test_default_handler (void)
g_test_trap_subprocess ("/logging/default-handler/subprocess/would-drop-env5", 0,
G_TEST_SUBPROCESS_DEFAULT);
g_test_trap_assert_passed ();
g_test_trap_subprocess ("/logging/default-handler/subprocess/would-drop-env-systemd", 0,
G_TEST_SUBPROCESS_DEFAULT);
g_test_trap_assert_passed ();
g_test_trap_subprocess ("/logging/default-handler/subprocess/would-drop-robustness", 0,
G_TEST_SUBPROCESS_DEFAULT);
g_test_trap_assert_passed ();
@ -1105,6 +1117,7 @@ main (int argc, char *argv[])
g_test_add_func ("/logging/default-handler/subprocess/would-drop-env3", test_default_handler_would_drop_env3);
g_test_add_func ("/logging/default-handler/subprocess/would-drop-env4", test_default_handler_would_drop_env4);
g_test_add_func ("/logging/default-handler/subprocess/would-drop-env5", test_default_handler_would_drop_env5);
g_test_add_func ("/logging/default-handler/subprocess/would-drop-env-systemd", test_default_handler_would_drop_env_systemd);
g_test_add_func ("/logging/default-handler/subprocess/would-drop-robustness", test_default_handler_would_drop_robustness);
g_test_add_func ("/logging/default-handler/subprocess/structured-logging-non-null-terminated-strings", test_default_handler_structured_logging_non_nul_terminated_strings);
g_test_add_func ("/logging/warnings", test_warnings);