main.py

# Copyright 2019 Google, LLC.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import json
import os

from flask import Flask, request


app = Flask(__name__)


@app.route("/", methods=["GET"])
def index():
    # This is set as a custom environment variable on deployment.
    # To automatically detect the current project, use the metadata server.
    # https://cloud.google.com/run/docs/reference/container-contract#metadata-server
    PROJECT = os.environ["GOOGLE_CLOUD_PROJECT"]

    # [START cloudrun_manual_logging]
    # [START run_manual_logging]
    # Uncomment and populate this variable in your code:
    # PROJECT = 'The project ID of your Cloud Run service';

    # Build structured log messages as an object.
    global_log_fields = {}

    # Add log correlation to nest all log messages.
    trace_header = request.headers.get("X-Cloud-Trace-Context")

    if trace_header and PROJECT:
        trace = trace_header.split("/")
        global_log_fields[
            "logging.googleapis.com/trace"
        ] = f"projects/{PROJECT}/traces/{trace[0]}"

    # Complete a structured log entry.
    entry = dict(
        severity="NOTICE",
        message="This is the default display field.",
        # Log viewer accesses 'component' as jsonPayload.component'.
        component="arbitrary-property",
        **global_log_fields,
    )

    print(json.dumps(entry))
    # [END run_manual_logging]
    # [END cloudrun_manual_logging]

    return "Hello Logger!"


if __name__ == "__main__":
    PORT = int(os.getenv("PORT")) if os.getenv("PORT") else 8080

    # This is used when running locally. Gunicorn is used to run the
    # application on Cloud Run. See entrypoint in Dockerfile.
    app.run(host="127.0.0.1", port=PORT, debug=True)