python_lambda: allow for library target branches and detect arch in install script

.github/actions/get_target_branch/action.yaml

@@ -16,7 +16,7 @@ runs:
       id: extract
       shell: bash
       run: |
-        branch=$(echo "${INPUTS_TEXT}" | grep -ioP '\[(?:java|dotnet|python|ruby|php|golang|cpp|agent|nodejs|rust)@[^]]+(?=\])' | tr -d '[:space:]' || true)
+        branch=$(echo "${INPUTS_TEXT}" | grep -ioP '\[(?:java|dotnet|python|python_lambda|ruby|php|golang|cpp|agent|nodejs|rust)@[^]]+(?=\])' | tr -d '[:space:]' || true)
 
         echo "target-branch=${branch#*@}" >> $GITHUB_OUTPUT
 

utils/build/docker/python_lambda/install_datadog_lambda.sh

@@ -10,11 +10,13 @@ if [ "$(find . -maxdepth 1 -name "*.zip" | wc -l)" = "1" ]; then
     unzip "${path}" -d /opt
 else
     echo "Fetching from latest GitHub release"
-    curl -fsSLO https://github.com/DataDog/datadog-lambda-python/releases/latest/download/datadog_lambda_py-amd64-3.13.zip
-    unzip -o datadog_lambda_py-amd64-3.13.zip -d /opt
+    ARCH=$(uname -m | sed 's/x86_64/amd64/' | sed 's/aarch64/arm64/')
+    echo https://github.com/DataDog/datadog-lambda-python/releases/latest/download/datadog_lambda_py-"$ARCH"-3.13.zip
+    curl -fsSLO https://github.com/DataDog/datadog-lambda-python/releases/latest/download/datadog_lambda_py-"$ARCH"-3.13.zip
+    unzip -o datadog_lambda_py-"$ARCH"-3.13.zip -d /opt
 
-    if [ ! -f datadog_lambda_py-amd64-3.13.zip ]; then
-        echo "Failed to download datadog_lambda_py-amd64-3.13.zip"
+    if [ ! -f datadog_lambda_py-"$ARCH"-3.13.zip ]; then
+        echo "Failed to download datadog_lambda_py-""$ARCH""-3.13.zip"
         exit 1
     fi
 fi

utils/scripts/load-binary.sh

@@ -351,9 +351,9 @@ elif [ "$TARGET" = "waf_rule_set" ]; then
 
 elif [ "$TARGET" = "python_lambda" ]; then
     assert_version_is_dev
-    assert_target_branch_is_not_set
 
-    get_github_action_artifact "DataDog/datadog-lambda-python" "build_layer.yml" "main" "datadog-lambda-python-3.13-amd64" "datadog_lambda_py-amd64-3.13.zip" "false"
+    LIBRARY_TARGET_BRANCH="${LIBRARY_TARGET_BRANCH:-main}"
+    get_github_action_artifact "DataDog/datadog-lambda-python" "build_layer.yml" $LIBRARY_TARGET_BRANCH "datadog-lambda-python-3.13-amd64" "datadog_lambda_py-amd64-3.13.zip" "false"
 
 elif [ "$TARGET" = "otel_collector" ]; then
     assert_version_is_dev