Introducing Workers Observability: logs, metrics, and queries – all in one place

We’re excited to announce Workers Observability – a new section in the Cloudflare Dashboard that allows you to query detailed log events across all Workers in your account to extract deeper insights.

In 2024, we set out to build the best first-party observability for any cloud platform. Since then, we’ve improved metrics reporting for all resources, launched Workers Logs to automatically ingest and store logs for Workers, and rebuilt real-time logs with improved filtering. However, observability insights have been limited to a single Worker.

Starting today, you can use Workers Observability to understand what is happening across all of your Workers:

• Workers Metrics Dashboard (Beta): A single dashboard to view metrics and logs from all of your Workers 

• Query Builder (Beta): Construct structured queries to explore your logs, extract metrics from logs, create graphical and tabular visualizations, and save queries for faster future investigations.

• Workers Logs: Now Generally Available, with a public API and improved invocation-based grouping.

The Query Builder allows you to interact with your logs, and answer the “why” to any question you have. You can find it by navigating to Workers & Pages > Observability in the dashboard.

Using the Query Builder, you can now answer more questions than ever. For example, this query shows the p90 wall time for 200 OK responses from the /reference endpoint is 6 milliseconds.

The key components to structuring a query in the Query Builder are:

• Visualizations: An aggregate function like average, count, percentile, or unique that performs a calculation on a group of values to return a single value. Each aggregate function returns a graph visualization and a summary table.

• Filters: A condition that allows you to exclude data not matching the criteria.

• Search: A condition that only returns the data matching the specified string.

• Group by: A function to collapse a field into only its distinct values, allowing you to more granularly apply aggregate functions.

• Order by: A sorting function to order the returned rows.

• Limits: A cap on the number of returned rows, allowing you to focus on what is important.

The Query Builder relies on structured logs for efficient indexed queries and extracting metrics from logs. Workers Observability natively supports and encourages structured logs. Structured logs store context-rich metadata as key-value pairs in the form of distinct fields (high dimensionality), each with many potential unique values (high cardinality). Invocation Logs, which can be enabled in your Worker, contain deep insights from Cloudflare’s network, and are a great example of a structured log. By logging important metadata as a structured log, you empower yourself to answer questions about your system that you couldn’t predict when writing the code. 

Internally at Cloudflare, we’ve already found tremendous value from this new product. During development, the Workers Observability team was able to use the Query Builder to discover a bug in the Workers Observability team’s staging environment. A query on the number of the events per script returned the following response:

After mapping this drop in recorded events against recent staging deployments, the team was able to isolate and root cause the introduction of the bug. Along with fixing the bug, the team also introduced new staging alerts to prevent errors like this from going unnoticed.

Queries built with the Query Builder or Workers Logs can be saved with a custom name and description. You can star your favorite queries, and also share them with your teammates using a shareable link, making it easier than ever to debug together and invest in developing visualizations from your telemetry data.

You can now monitor CPU time and wall time for every Workers invocation across all of our observability offerings, including Tail Workers, Workers Logpush, and Workers Logs. These metrics help show how much time is spent executing code compared to the total elapsed time for the invocation, including I/O time.

For example, using the CPU time and wall time surfaced in the Invocation Log, you can use the Query Builder to show the p90 CPU time and wall time traffic for a single Worker script.

In February, we released a new view into your Workers’ metrics to help you monitor your gradual deployments with improved visualizations. Today, we are also launching a new Workers Metrics overview page in the Observability tab. Now you can easily compare metrics across Workers and understand the current state of your deployments, all from a single view.

Invocations are mechanisms to trigger the execution of a Worker or Durable Object in response to an event, such as an alarm, cron job, or a fetch. 

When the Worker or Durable Object executes, log events are emitted. To date, we have surfaced logs in an events view where each log is ordered by the time it was published. 

We’re now introducing an Invocations View, so you can group and view all logs from each invocation. These views are available in each Worker’s view and the Workers Observability tab.

You can now use the Workers Observability API to programmatically retrieve your telemetry data and populate the tool of your choice.

The API allows you to automate, integrate, and customize in ways that our dashboard may not. For example, you may want to analyze your logs in a notebook or correlate your Workers logs with logs from a different source.  Leveraging the Workers Observability API can help you optimize your monitoring strategy, automate repetitive tasks, and improve flexibility in how you interact with your telemetry data.

To use Workers Logs, enable it in your Workers’ settings in the dashboard or add the following configuration to your Workers’ wrangler file:

# wrangler.jsonc

{
  "observability": {
    "enabled": true,
    "logs": {
      "invocation_logs": true,
      "head_sampling_rate": 1
    }
  }
}

We’re just getting started. We have lots in store to help make Cloudflare’s developer observability best-in-class. Join us in Discord in the #workers-observability channel for feedback and feature requests.