feat: skip GCP ADC authent when GCP_JWT is not present

Don't set GCP ADC authent when GCP_JWT is not present to preserve gitlab-ci-local with local GCP authentication

templates/gitlab-ci-python-gcp.yml

@@ -20,10 +20,11 @@ variables:
   GCP_OIDC_PROVIDER: $[[ inputs.gcp-oidc-provider ]]
 
 .python-gcp-adc:
-  - set -e
-  - echo -e "[\\e[1;94mINFO\\e[0m] Installing GCP authentication with env GOOGLE_APPLICATION_CREDENTIALS file"
-  - echo $GCP_JWT > "$CI_BUILDS_DIR/.auth_token.jwt"
-  - |-
+  - |
+    if [[ "$GCP_JWT" ]]
+    then
+      echo -e "[\\e[1;94mINFO\\e[0m] Installing GCP authentication with env GOOGLE_APPLICATION_CREDENTIALS file"
+      echo $GCP_JWT > "$CI_BUILDS_DIR/.auth_token.jwt"
       cat << EOF > "$CI_BUILDS_DIR/google_application_credentials.json"
       {
         "type": "external_account",
@@ -36,7 +37,10 @@ variables:
         "service_account_impersonation_url": "https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/${GCP_OIDC_ACCOUNT}:generateAccessToken"
       }
     EOF
-  - export GOOGLE_APPLICATION_CREDENTIALS="$CI_BUILDS_DIR/google_application_credentials.json"
+      export GOOGLE_APPLICATION_CREDENTIALS="$CI_BUILDS_DIR/google_application_credentials.json"
+    else
+      echo '[WARN] $GCP_JWT is not set: cannot setup Application Default Credentials (ADC) authentication'
+    fi
 
 .python-base:
   image: $PYTHON_IMAGE