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| -rw-r--r-- | HACKING.md | 58 | ||||
| -rw-r--r-- | README.md | 2 |
2 files changed, 59 insertions, 1 deletions
diff --git a/HACKING.md b/HACKING.md new file mode 100644 index 000000000..389b9c2a1 --- /dev/null +++ b/HACKING.md @@ -0,0 +1,58 @@ +# Logging + +The following environment variables control logging from Tracker daemons: + + * `TRACKER_VERBOSITY`: takes a value of 1, 2 or 3 and causes increasing + amounts of log output from Tracker code to be written to stdout. + * `G_MESSAGES_DEBUG`: controls log output from GLib-based libraries that + are used in the Tracker process. Use `G_MESSAGES_DEBUG=all` for maximal + log output. + +Internally, Tracker will set `G_MESSAGES_DEBUG=Tracker` if `TRACKER_VERBOSITY` +is set and `G_MESSAGES_DEBUG` is not set, to enable printing of its own log +messages to stdout. + +You can set these variables when using `tracker-sandbox`, and when running the +Tracker test suite. Note that Meson will not print log output from tests by +default, use `meson test --verbose` or `meson test --print-errorlogs` to +enable. + +The functional tests understand an additional variable, `TRACKER_TESTS_VERBOSE` +with can be set to `1` or `yes` to see detailed logging from the test harness +itself, and full log output from the internal D-Bus daemon. By default, these +tests filter output from the D-Bus daemon to only show log messages from +Tracker processes. Anything written directly to stdout, for example by +`g_print()` or by the dbus-daemon itself, will not be displayed unless +`TRACKER_TESTS_VERBOSE` is set. + +# Attaching a debugger to Tracker daemons + +Tracker daemons are not started directly. Instead they are started by the D-Bus +daemon by request. When using tracker-sandbox or the functional-tests, it's +difficult to start the daemon manually under `gdb`. + +Instead, we recommend adding a 10 second timeout at the top of the daemon's +main() function. In Vala code, try this: + + print("Pausing to attach debugger. Run: gdb attach %i\n", Posix.getpid()); + Posix.usleep(10 * 1000 * 1000); + print("Waking up again\n"); + +Run the test, using the `meson build --timeout-multiplier=10000` +option to avoid your process being killed by the test runner. When you see +the 'Pausing' message, run the `gdb attach``command in another terminal within +10 seconds. + +# Running Tracker daemons under Valgrind + +The Tracker daemons are launched using D-Bus autolaunch. When running them from +the source tree using tracker-sandbox or the functional tests, the commandline +is controlled by the D-Bus .service.in files stored in `./tests/services`. Just +change the `Exec=` line to add Valgrind, like this: + + Exec=/usr/bin/valgrind @abs_top_builddir@/src/tracker-store/tracker-store + +By default the tracker-sandbox utility and the functional-tests will only +show output from Tracker code. For the functional-tests, set +TRACKER_TESTS_VERBOSE=1 to see output from Valgrind. For tracker-sandbox use +the `--debug-dbus` option. @@ -131,4 +131,4 @@ interactive shell inside the sandbox. From here you can use debugging tools such as GDB. For more information about developing Tracker, look at -https://wiki.gnome.org/Projects/Tracker. +https://wiki.gnome.org/Projects/Tracker and HACKING.md. |