[libcamera-devel] [PATCH v11] test: gstreamer: Add test for gstreamer single stream

[Laurent Pinchart]

Hi Paul,

On Sat, Aug 14, 2021 at 02:13:53PM +0900, paul.elder at ideasonboard.com wrote:
> On Sat, Aug 14, 2021 at 02:46:52AM +0300, Laurent Pinchart wrote:
> > From: Vedant Paranjape <vedantparanjape160201 at gmail.com>
> > 
> > This patch adds a test to test if single stream using libcamera's
> > gstreamer element works.
> > 
> > We need to work around two distinct issues with ASan when enabled in the
> > build:
> > 
> > - glib has a known leak at initialization time. This is covered by the
> >   suppression file shipped with glib, but it's not clear how to use it
> >   automatically. For now, disable leak detection to avoid test failures.
> > 
> > - GStreamer spawns a child process to scan plugins. If GStreamer is
> >   compiled without ASan (which is likely) but libcamera is, dlopen()ing
> >   the libcamera plugin will cause an ASan link order verification
> >   failure. Disable the verification child processes to work around the
> >   problem. This requires gcc 8 or newer.
> > 
> > Signed-off-by: Vedant Paranjape <vedantparanjape160201 at gmail.com>
> > Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
> > Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > Tested-by: Kieran Bingham <kieran.bingham@@ideasonboard.com>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> > This version incorporates changes coming from my review of v10, and
> > fixes for ASan issues. ASan is a bit of a pain with GStreamer, for two
> > independent reasons as explained in the commit message. I'd like to find
> > a way to use leak suppression files to handle the glib initialization
> > leak, but that's a big rabbit hole. The workaround for the second issue
> > is acceptable in my opinion.
> > 
> > The biggest trouble with these workarounds is that they don't work with
> > gcc version older than 8. As the stable version of the most common Linux
> > distributions ship gcc 8 or newer, skipping this test for gcc 7 (which
> > is the oldest version that libcamera supports) is also acceptable in my
> > opinion.
> > 
> > Changes since v10:
> > 
> > - Disable ASan leak detection
> > - Disable ASan link order verification for child processes
> > - Include source_path.h
> > - Remove unneeded explicit std::string construction
> > - Declare variables at usage site
> > - Make constants constexpr
> > - Add a variable for the message type
> > - Blank space fixes
> > ---
> >  .../gstreamer_single_stream_test.cpp          | 188 ++++++++++++++++++
> >  test/gstreamer/meson.build                    |  19 ++
> >  test/meson.build                              |   1 +
> >  3 files changed, 208 insertions(+)
> >  create mode 100644 test/gstreamer/gstreamer_single_stream_test.cpp
> >  create mode 100644 test/gstreamer/meson.build
> > 
> > diff --git a/test/gstreamer/gstreamer_single_stream_test.cpp b/test/gstreamer/gstreamer_single_stream_test.cpp
> > new file mode 100644
> > index 000000000000..e26673b3471a
> > --- /dev/null
> > +++ b/test/gstreamer/gstreamer_single_stream_test.cpp
> > @@ -0,0 +1,188 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +/*
> > + * Copyright (C) 2021, Vedant Paranjape
> > + *
> > + * ipa_interface_test.cpp - Test the IPA interface
> 
> Maybe we should change the description.

As good point. Funny how this can stay unnoticed for 11 versions.

I'll update it to

 * gstreamer_single_stream_test.cpp - GStreamer single stream capture test

> > + */
> > +
> > +#include <iostream>
> > +#include <unistd.h>
> > +
> > +#include <libcamera/base/utils.h>
> > +
> > +#include "libcamera/internal/source_paths.h"
> > +
> > +#include <gst/gst.h>
> > +
> > +#include "test.h"
> > +
> > +using namespace std;
> > +
> > +extern "C" {
> > +const char *__asan_default_options()
> > +{
> > +	/*
> > +	 * Disable leak detection due to a known global variable initialization
> > +	 * leak in glib's g_quark_init(). This should ideally be handled by
> > +	 * using a suppression file instead of disabling leak detection.
> > +	 */
> > +	return "detect_leaks=false";
> > +}
> > +}
> > +
> > +class GstreamerSingleStreamTest : public Test
> > +{
> > +protected:
> > +	int init() override
> > +	{
> > +		/*
> > +		 * GStreamer spawns a process to run the gst-plugin-scanner
> > +		 * helper. If libcamera is compiled with ASan enabled, and as
> > +		 * GStreamer is most likely not, this will cause the ASan link
> > +		 * order check to fail when gst-plugin-scanner dlopen()s the
> > +		 * plugin as many libraries will have already been loaded by
> > +		 * then. Work around this issue by disabling the link order
> > +		 * check. This will only affect child processes, as ASan is
> > +		 * already loaded for this process by the time this code is
> > +		 * executed, and should thus hopefully be safe.
> > +		 *
> > +		 * This option is not available in gcc older than 8, the only
> > +		 * option in that case is to skip the test.
> > +		 */
> > +#if defined(__SANITIZE_ADDRESS__) && !defined(__clang__) && __GNUC__ < 8
> > +		return TestSkip;
> > +#endif
> > +		setenv("ASAN_OPTIONS", "verify_asan_link_order=0", 1);
> > +
> > +		/* Initialize GStreamer */
> > +		GError *errInit = nullptr;
> > +		if (!gst_init_check(nullptr, nullptr, &errInit)) {
> > +			g_printerr("Could not initialize GStreamer: %s\n",
> > +				   errInit ? errInit->message : "unknown error");
> > +			if (errInit)
> > +				g_error_free(errInit);
> > +
> > +			return TestFail;
> > +		}
> > +
> > +		/*
> > +		 * Remove the system libcamera plugin, if any, and add the
> > +		 * plugin from the build directory.
> > +		 */
> > +		GstRegistry *registry = gst_registry_get();
> > +		GstPlugin *plugin = gst_registry_lookup(registry, "libgstlibcamera.so");
> > +		if (plugin) {
> > +			gst_registry_remove_plugin(registry, plugin);
> > +			gst_object_unref(plugin);
> > +		}
> > +
> > +		std::string path = libcamera::utils::libcameraBuildPath()
> > +				 + "src/gstreamer";
> > +		if (!gst_registry_scan_path(registry, path.c_str())) {
> > +			g_printerr("Failed to add plugin to registry\n");
> > +			gst_deinit();
> > +			return TestFail;
> > +		}
> > +
> > +		/* Create the elements */
> > +		libcameraSrc_ = gst_element_factory_make("libcamerasrc", "libcamera");
> > +		convert0_ = gst_element_factory_make("videoconvert", "convert0");
> > +		sink0_ = gst_element_factory_make("fakesink", "sink0");
> > +
> > +		/* Create the empty pipeline_ */
> > +		pipeline_ = gst_pipeline_new("test-pipeline");
> > +
> > +		if (!pipeline_ || !convert0_ || !sink0_ || !libcameraSrc_) {
> > +			g_printerr("Not all elements could be created. %p.%p.%p.%p\n",
> > +				   pipeline_, convert0_, sink0_, libcameraSrc_);
> > +			if (pipeline_)
> > +				gst_object_unref(pipeline_);
> > +			if (convert0_)
> > +				gst_object_unref(convert0_);
> > +			if (sink0_)
> > +				gst_object_unref(sink0_);
> > +			if (libcameraSrc_)
> > +				gst_object_unref(libcameraSrc_);
> > +			gst_deinit();
> > +
> > +			return TestFail;
> > +		}
> > +
> > +		return TestPass;
> > +	}
> > +
> > +	void cleanup() override
> > +	{
> > +		gst_object_unref(pipeline_);
> > +		gst_deinit();
> > +	}
> > +
> > +	int run() override
> > +	{
> > +		GstStateChangeReturn ret;
> > +
> > +		/* Build the pipeline */
> > +		gst_bin_add_many(GST_BIN(pipeline_), libcameraSrc_, convert0_, sink0_, NULL);
> > +		if (gst_element_link_many(libcameraSrc_, convert0_, sink0_, NULL) != TRUE) {
> > +			g_printerr("Elements could not be linked.\n");
> > +			return TestFail;
> > +		}
> > +
> > +		/* Start playing */
> > +		ret = gst_element_set_state(pipeline_, GST_STATE_PLAYING);
> > +		if (ret == GST_STATE_CHANGE_FAILURE) {
> > +			g_printerr("Unable to set the pipeline to the playing state.\n");
> > +			return TestFail;
> > +		}
> > +
> > +		/* Wait until error or EOS or timeout after 2 seconds */
> > +		constexpr GstMessageType msgType =
> > +			static_cast<GstMessageType>(GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
> > +		constexpr GstClockTime timeout = 2000000000;
> > +
> > +		g_autoptr(GstBus) bus = gst_element_get_bus(pipeline_);
> > +		g_autoptr(GstMessage) msg = gst_bus_timed_pop_filtered(bus, timeout, msgType);
> > +
> > +		gst_element_set_state(pipeline_, GST_STATE_NULL);
> > +
> > +		/* Parse error message */
> > +		if (msg == NULL)
> > +			return TestPass;
> > +
> > +		switch (GST_MESSAGE_TYPE(msg)) {
> > +		case GST_MESSAGE_ERROR:
> > +			gstreamer_print_error(msg);
> > +			break;
> > +		case GST_MESSAGE_EOS:
> > +			g_print("End-Of-Stream reached.\n");
> > +			break;
> > +		default:
> > +			g_printerr("Unexpected message received.\n");
> > +			break;
> > +		}
> > +
> > +		return TestFail;
> > +	}
> > +
> > +private:
> > +	void gstreamer_print_error(GstMessage *msg)
> > +	{
> > +		GError *err;
> > +		gchar *debug_info;
> > +
> > +		gst_message_parse_error(msg, &err, &debug_info);
> > +		g_printerr("Error received from element %s: %s\n",
> > +			   GST_OBJECT_NAME(msg->src), err->message);
> > +		g_printerr("Debugging information: %s\n",
> > +			   debug_info ? debug_info : "none");
> > +		g_clear_error(&err);
> > +		g_free(debug_info);
> > +	}
> > +
> > +	GstElement *pipeline_;
> > +	GstElement *libcameraSrc_;
> > +	GstElement *convert0_;
> > +	GstElement *sink0_;
> > +};
> > +
> > +TEST_REGISTER(GstreamerSingleStreamTest)
> > diff --git a/test/gstreamer/meson.build b/test/gstreamer/meson.build
> > new file mode 100644
> > index 000000000000..b99aa0da0ba3
> > --- /dev/null
> > +++ b/test/gstreamer/meson.build
> > @@ -0,0 +1,19 @@
> > +# SPDX-License-Identifier: CC0-1.0
> > +
> > +if not gst_enabled
> > +    subdir_done()
> > +endif
> > +
> > +gstreamer_tests = [
> > +    ['single_stream_test',   'gstreamer_single_stream_test.cpp'],
> > +]
> > +gstreamer_dep = dependency('gstreamer-1.0', required: true)
> > +
> > +foreach t : gstreamer_tests
> > +    exe = executable(t[0], t[1],
> > +                     dependencies : [libcamera_private, gstreamer_dep],
> > +                     link_with : test_libraries,
> > +                     include_directories : test_includes_internal)
> > +
> > +    test(t[0], exe, suite : 'gstreamer', is_parallel : false)
> > +endforeach
> > diff --git a/test/meson.build b/test/meson.build
> > index 3bceb5df586f..d0466f17d7b6 100644
> > --- a/test/meson.build
> > +++ b/test/meson.build
> > @@ -11,6 +11,7 @@ subdir('libtest')
> >  
> >  subdir('camera')
> >  subdir('controls')
> > +subdir('gstreamer')
> >  subdir('ipa')
> >  subdir('ipc')
> >  subdir('log')

-- 
Regards,

Laurent Pinchart