feat(tracer): Autodetect lambda execution env

Author: Michael Brewer

aws_lambda_powertools/shared/constants.py

@@ -12,10 +12,9 @@
 
 EVENT_HANDLER_DEBUG_ENV: str = "POWERTOOLS_EVENT_HANDLER_DEBUG"
 
-SAM_LOCAL_ENV: str = "AWS_SAM_LOCAL"
-CHALICE_LOCAL_ENV: str = "AWS_CHALICE_CLI_MODE"
 SERVICE_NAME_ENV: str = "POWERTOOLS_SERVICE_NAME"
 XRAY_TRACE_ID_ENV: str = "_X_AMZN_TRACE_ID"
+LAMBDA_TASK_ROOT_ENV: str = "LAMBDA_TASK_ROOT"
 
 XRAY_SDK_MODULE: str = "aws_xray_sdk"
 XRAY_SDK_CORE_MODULE: str = "aws_xray_sdk.core"

aws_lambda_powertools/tracing/tracer.py

@@ -719,16 +719,15 @@ def _is_tracer_disabled() -> Union[bool, str]:
         Union[bool, str]
         """
         logger.debug("Verifying whether Tracing has been disabled")
-        is_lambda_sam_cli = os.getenv(constants.SAM_LOCAL_ENV)
-        is_chalice_cli = os.getenv(constants.CHALICE_LOCAL_ENV)
+        is_lambda_env = os.getenv(constants.LAMBDA_TASK_ROOT_ENV)
         is_disabled = resolve_truthy_env_var_choice(env=os.getenv(constants.TRACER_DISABLED_ENV, "false"))
 
         if is_disabled:
             logger.debug("Tracing has been disabled via env var POWERTOOLS_TRACE_DISABLED")
             return is_disabled
 
-        if is_lambda_sam_cli or is_chalice_cli:
-            logger.debug("Running under SAM CLI env or not in Lambda env; disabling Tracing")
+        if not is_lambda_env:
+            logger.debug("Running outside Lambda env; disabling Tracing")
             return True
 
         return False

tests/functional/test_tracing.py

@@ -60,26 +60,11 @@ def greeting(name, message):
     greeting(name="Foo", message="Bar")
 
 
-def test_tracer_lambda_emulator(monkeypatch, dummy_response):
-    # GIVEN tracer runs locally
-    monkeypatch.setenv("AWS_SAM_LOCAL", "true")
+def test_tracer_lambda_outside_lambda_env(monkeypatch, dummy_response):
+    # GIVEN tracer runs locally (ie: `LAMBDA_TASK_ROOT` is not set)
     tracer = Tracer()
 
-    # WHEN a lambda function is run through SAM CLI
-    @tracer.capture_lambda_handler
-    def handler(event, context):
-        return dummy_response
-
-    # THEN tracer should run in disabled mode, and not raise an Exception
-    handler({}, {})
-
-
-def test_tracer_chalice_cli_mode(monkeypatch, dummy_response):
-    # GIVEN tracer runs locally
-    monkeypatch.setenv("AWS_CHALICE_CLI_MODE", "true")
-    tracer = Tracer()
-
-    # WHEN a lambda function is run through the Chalice CLI.
+    # WHEN a lambda function is run through outside of a lambda
     @tracer.capture_lambda_handler
     def handler(event, context):
         return dummy_response

tests/unit/test_tracing.py

@@ -125,9 +125,11 @@ def greeting(name, message):
     )
 
 
-def test_tracer_custom_metadata(mocker, dummy_response, provider_stub):
+def test_tracer_custom_metadata(monkeypatch, mocker, dummy_response, provider_stub):
     # GIVEN Tracer is initialized with booking as the service name
+    monkeypatch.setenv("LAMBDA_TASK_ROOT", "/opt/")
     put_metadata_mock = mocker.MagicMock()
+
     provider = provider_stub(put_metadata_mock=put_metadata_mock)
     tracer = Tracer(provider=provider, service="booking")
 
@@ -143,8 +145,9 @@ def test_tracer_custom_metadata(mocker, dummy_response, provider_stub):
     )
 
 
-def test_tracer_custom_annotation(mocker, dummy_response, provider_stub):
+def test_tracer_custom_annotation(monkeypatch, mocker, dummy_response, provider_stub):
     # GIVEN Tracer is initialized
+    monkeypatch.setenv("LAMBDA_TASK_ROOT", "/opt/")
     put_annotation_mock = mocker.MagicMock()
     provider = provider_stub(put_annotation_mock=put_annotation_mock)
     tracer = Tracer(provider=provider)
@@ -214,8 +217,9 @@ def greeting(name, message):
 
 
 @mock.patch("aws_lambda_powertools.tracing.tracer.aws_xray_sdk.core.patch")
-def test_tracer_patch_modules(xray_patch_mock, mocker):
+def test_tracer_patch_modules(xray_patch_mock, monkeypatch, mocker):
     # GIVEN tracer is initialized with a list of modules to patch
+    monkeypatch.setenv("LAMBDA_TASK_ROOT", "/opt/")
     modules = ["boto3"]
 
     # WHEN modules are supported by X-Ray