Update how profiler enabled flag is checked (#4621)

Start to enable Cloud Profiler for clusterfuzz by using the flag in the
project config yaml. This change is supported by a PR in clusterfuzz
configs repo.

In addition, remove profiler calls from fuzzer engines, since having it
only in the bot startup is enough granularity.

Author: ViniciustCosta

src/clusterfuzz/_internal/bot/fuzzers/afl/launcher.py

@@ -43,7 +43,6 @@
 from clusterfuzz._internal.bot.fuzzers.afl.fuzzer import write_dummy_file
 from clusterfuzz._internal.fuzzing import strategy
 from clusterfuzz._internal.metrics import logs
-from clusterfuzz._internal.metrics import profiler
 from clusterfuzz._internal.platforms import android
 from clusterfuzz._internal.system import environment
 from clusterfuzz._internal.system import new_process
@@ -1661,7 +1660,6 @@ def main(argv):
   # same python process.
   logs.configure('run_fuzzer')
   _verify_system_config()
-  profiler.start_if_needed('afl_launcher')
 
   build_directory = environment.get_value('BUILD_DIR')
   fuzzer_path = engine_common.find_fuzzer_path(build_directory, target_name)

src/clusterfuzz/_internal/bot/fuzzers/libFuzzer/engine.py

@@ -29,7 +29,6 @@
 from clusterfuzz._internal.bot.fuzzers.libFuzzer import stats
 from clusterfuzz._internal.fuzzing import strategy
 from clusterfuzz._internal.metrics import logs
-from clusterfuzz._internal.metrics import profiler
 from clusterfuzz._internal.system import environment
 from clusterfuzz._internal.system import shell
 from clusterfuzz.fuzz import engine
@@ -280,7 +279,6 @@ def fuzz(self, target_path, options, reproducers_dir, max_time):
     Returns:
       A FuzzResult object.
     """
-    profiler.start_if_needed('libfuzzer_fuzz')
     libfuzzer.set_sanitizer_options(target_path)
     runner = libfuzzer.get_runner(target_path)
 

src/clusterfuzz/_internal/metrics/profiler.py

@@ -13,14 +13,16 @@
 # limitations under the License.
 """Profiling functions."""
 from clusterfuzz._internal.base import utils
+from clusterfuzz._internal.config import local_config
 from clusterfuzz._internal.metrics import logs
 from clusterfuzz._internal.system import environment
 
 
 def start_if_needed(service):
-  """Start Google Cloud Profiler if |USE_PYTHON_PROFILER| environment variable
-  is set."""
-  if not environment.get_value('USE_PYTHON_PROFILER'):
+  """Start Google Cloud Profiler if profiling key in project config
+  is enabled."""
+  config = local_config.ProjectConfig()
+  if not config.get('profiling.enabled', False):
     return True
 
   project_id = utils.get_application_id()