Here's a quick summary of what we will be doing in this guide

• Create and configure App Engine
• Create Pub/Sub topic
• Create Log Router to route the App Engine logs to SigNoz
• Create Compute Engine instance
• Create OTel Collector to route logs from Pub/Sub topic to SigNoz Cloud
• Invoke the deployed App Engine service to generate logs
• Send and Visualize the logs in SigNoz Cloud

Prerequisites

• Google Cloud account with administrative privilege or App Engine Admin privilege.
• SigNoz Cloud Account (we are using SigNoz Cloud for this demonstration, we will also need ingestion details. To get your Ingestion Key and Ingestion URL, sign-in to your SigNoz Cloud Account and go to Settings >> Ingestion Settings)
• Access to a project in GCP
• Cloud Build API is enabled

Get started with App Engine Configuration

Create the App Engine service using the following steps:

Step 1: Install the Google Cloud CLI.

Step 2: To initialize the gcloud CLI, run the following command:

gcloud init

Step 3: Run the following gcloud command to enable App Engine and create the associated application resources. Note that the location you select cannot be changed later.

gcloud app create

Step 4: In this example, we will be building the Python 3 application. For this,

1. Download the sample application repository using Git:

git clone https://github.com/GoogleCloudPlatform/python-docs-samples

Alternatively, you can download the sample as a zip file and then extract it.

2. Navigate to the directory that contains a copy of the files from the previous step:

cd python-docs-samples/appengine/standard_python3/hello_world

Note that we have app.yaml file located in this folder.

3. You can modify the main.py file in this folder using vi main.py to include a couple of print statements which will be logged when the service is invoked.

@app.route("/")
def hello():
    """Return a friendly HTTP greeting.

    Returns:
        A string with the words 'Hello World!'.
    """
    print("Starting the hello world app engine application...")  # <- new print statement added
    return "Hello World!"

4. When on this folder which contains app.yaml, you can deploy your service using the command:

gcloud app deploy

5. On running the above command, the service will get deployed on the App Engine, and you will get the logs containing the endpoint which can be used to trigger the deployed service (highlighted in red in the screenshot).

Open the URL in the new browser which will invoke the service and put out the print statements in the logs.

Viewing the logs

• In the GCP console, search for Logs and go to Logs Explorer service.
• Check for the recent logs or use the Query textbox to search for the logs containing the print statements from the service deployed to the App Engine.

Create PubSub Topic

Follow the steps mentioned in the Creating Pub/Sub Topic document to create the Pub/Sub topic.

Create Log Router to Pub/Sub Topic

Follow the steps mentioned in the Log Router Setup document to create the Log Router.

To ensure you filter out only the App Engine logs, use the following filter conditions:

resource.type="gae_app"

Setup OTel Collector

Follow the steps mentioned in the Creating Compute Engine document to create the Compute Engine instance.

Install OTel Collector as agent

Firstly, we will establish the authentication using the following commands:

1. Initialize gcloud:

gcloud init

2. Authenticate into GCP:

gcloud auth application-default login

Let us now proceed to the OTel Collector installation:

Step 1: Download otel-collector tar.gz for your architecture

wget https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v0.88.0/otelcol-contrib_0.88.0_linux_amd64.tar.gz

Step 2: Extract otel-collector tar.gz to the otelcol-contrib folder

mkdir otelcol-contrib && tar xvzf otelcol-contrib_0.88.0_linux_amd64.tar.gz -C otelcol-contrib

Step 3: Create config.yaml in the folder otelcol-contrib with the below content in it. Replace <region> with the appropriate SigNoz Cloud region. Replace SIGNOZ_INGESTION_KEY with what is provided by SigNoz:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
  googlecloudpubsub:
    project: <gcp-project-id>
    subscription: projects/<gcp-project-id>/subscriptions/<pubsub-topic's-subscription>
    encoding: raw_text
processors:
  batch: {}
exporters:
  otlp:
    endpoint: "ingest.<region>.signoz.cloud:443"
    tls:
      insecure: false
    headers:
      "signoz-access-token": "<SigNoz-Key>"
service:
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]
    metrics:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]
    logs:
      receivers: [otlp, googlecloudpubsub]
      processors: [batch]
      exporters: [otlp]

Step 4: Once we are done with the above configurations, we can now run the collector service with the following command:

From the otelcol-contrib, run the following command:

./otelcol-contrib --config ./config.yaml

Run in background

If you want to run OTel Collector process in the background:

./otelcol-contrib --config ./config.yaml &> otelcol-output.log & echo "$!" > otel-pid

The above command sends the output of the otel-collector to otelcol-output.log file and prints the process id of the background running OTel Collector process to the otel-pid file.

If you want to see the output of the logs you’ve just set up for the background process, you may look it up with:

tail -f -n 50 otelcol-output.log

You can now trigger the App Engine service URL a few times, and see the logs from the App Engine on SigNoz Cloud.