Hash AWS Lambda test functions based on current revision (#2557)

We were using the current SDK version for determining whether an AWS Lambda function should be reused, so e.g. on PRs, this would reuse the existing functions instead of creating new ones with any changes from the PR. Changing this to use the current commit instead.

Also, use a 6 character hash instead of 5 characters, just to lower the chance for collisions a bit.

sentry_sdk/utils.py

@@ -95,16 +95,11 @@ def _get_debug_hub():
     pass
 
 
-def get_default_release():
+def get_git_revision():
     # type: () -> Optional[str]
-    """Try to guess a default release."""
-    release = os.environ.get("SENTRY_RELEASE")
-    if release:
-        return release
-
     with open(os.path.devnull, "w+") as null:
         try:
-            release = (
+            revision = (
                 subprocess.Popen(
                     ["git", "rev-parse", "HEAD"],
                     stdout=subprocess.PIPE,
@@ -116,10 +111,21 @@ def get_default_release():
                 .decode("utf-8")
             )
         except (OSError, IOError):
-            pass
+            return None
 
-        if release:
-            return release
+    return revision
+
+
+def get_default_release():
+    # type: () -> Optional[str]
+    """Try to guess a default release."""
+    release = os.environ.get("SENTRY_RELEASE")
+    if release:
+        return release
+
+    release = get_git_revision()
+    if release is not None:
+        return release
 
     for var in (
         "HEROKU_SLUG_COMMIT",

tests/integrations/aws_lambda/client.py

@@ -8,6 +8,7 @@
 import tempfile
 
 from sentry_sdk.consts import VERSION as SDK_VERSION
+from sentry_sdk.utils import get_git_revision
 
 AWS_REGION_NAME = "us-east-1"
 AWS_CREDENTIALS = {
@@ -226,7 +227,8 @@ def run_lambda_function(
     # Making a unique function name depending on all the code that is run in it (function code plus SDK version)
     # The name needs to be short so the generated event/envelope json blobs are small enough to be output
     # in the log result of the Lambda function.
-    function_hash = hashlib.shake_256((code + SDK_VERSION).encode("utf-8")).hexdigest(5)
+    rev = get_git_revision() or SDK_VERSION
+    function_hash = hashlib.shake_256((code + rev).encode("utf-8")).hexdigest(6)
     fn_name = "test_{}".format(function_hash)
     full_fn_name = "{}_{}".format(
         fn_name, runtime.replace(".", "").replace("python", "py")