Unlocking Insights with Heroku Logs: Complete Guide

Heroku is a popular platform for deploying and scaling applications, and one of its standout features is its centralized logging system. Heroku logs give you visibility into your application’s behaviour, infrastructure events, and platform activities. When paired with a robust monitoring solution like Atatus, you can transform raw log data into actionable insights that keep your applications running smoothly.

In this blog, we will explore the world of Heroku logs, how to manage them effectively, and how to supercharge their potential by integrating them with Atatus for enhanced observability.

Let's get started!

What are Heroku Logs?

Heroku provides a centralized logging system that allows you to collect and view logs from your app, platform, and any add-ons you are using. These logs are streamed into Logplex, which acts as Heroku's real-time log router and delivery system.

Heroku’s logging system consists of various log types:

System Logs: These are events generated by the Heroku platform itself, such as when your app's dynos are started or stopped, or when you scale your app. These logs help you track the state of your Heroku infrastructure.
Application Logs: These logs include output from your application, such as print statements or errors. These are typically logged to standard output (stdout) or standard error (stderr) and are crucial for debugging and monitoring application health.
API Logs: API logs capture events related to the management of your Heroku app, like scaling dynos, deploying new versions, and administrative actions. These logs give you insight into what’s happening on the platform level, separate from the application logs.
Add-on Logs: If you're using Heroku add-ons like databases, caching services, or monitoring tools, their logs will also be captured. These logs are useful for tracking the performance of external services integrated into your app.

All these logs are aggregated into Logplex, and you can access them through the Heroku CLI or configure them to be sent to external log management systems for further analysis and storage.

What is Logplex?

At the core of Heroku’s logging system is Logplex, a real-time log routing and delivery service. Logplex is responsible for aggregating logs from various sources: application logs, system logs, API logs, and add-on logs and sending them to the appropriate destinations, such as the Heroku CLI, external logging systems, or cloud-based log aggregation services.

Logplex allows Heroku to handle logs in a fault-tolerant way, ensuring that logs are never lost and can be processed efficiently. This system is designed to scale horizontally, meaning it can handle the heavy traffic of logs from thousands of dynos and applications, making it well-suited for modern, distributed cloud environments.

One of the key features of Logplex is that it abstracts the complexity of log management from developers. You don't need to worry about maintaining or scaling your logging infrastructure, Heroku handles it all. Instead, you can focus on collecting and analyzing the logs that matter to your application’s performance.

What are Log Drains?

In Heroku, log drains are mechanisms that allow you to forward logs from Logplex to external services for analysis, storage, and monitoring. Log drains are essentially HTTP endpoints (URLs) that you configure in your Heroku app, and Logplex streams the logs to those endpoints in real-time.

By using log drains, you can integrate your Heroku logs with third-party log management and monitoring services such as Atatus, Datadog, Splunk, or even custom log management systems. This integration helps you use powerful tools like advanced search, log filtering, custom dashboards, and alerting for better visibility into your app's performance and errors.

How Log Drains work?

Logplex collects your Heroku app’s logs and sends them to the destinations you have set up, ensuring real-time delivery and reliability. Here’s how it works:

Logplex Routing: When your Heroku application generates logs, Logplex processes them in real-time. These logs are then sent to any configured log drains.

Forwarding Logs: Logplex forwards the log data to the configured endpoints. You can forward your logs to multiple destinations, depending on your needs. For example, you might send critical error logs to one service for immediate analysis while storing all logs in a centralized storage service for archiving.

Real-Time Delivery: Logplex ensures that logs are delivered as soon as they are generated. This means that you can react quickly to incidents, such as system failures or application errors, and access logs in near real-time for investigation and troubleshooting.

Fault-Tolerant: Logplex is designed for reliability. Even if one log drain becomes temporarily unavailable, logs will not be lost. They will be retried until they are successfully delivered, ensuring that your logs are always captured.

Setting up Log Drains for External Monitoring

Integrating Heroku logs with an external monitoring system can drastically improve your ability to monitor, troubleshoot, and analyze your applications. For example, Atatus is a powerful observability tool that allows you to monitor your app's health, performance, and errors through custom dashboards, real-time alerts, and deep log analysis.

Here’s how you can configure log drains to send your Heroku logs to Atatus:

Step 1: Get Your Atatus Log Endpoint and API Key

Before you can set up a log drain, you need to sign up for Atatus and get the following details:

The log ingestion endpoint for Atatus (a URL where your logs will be sent).
Your Atatus API key, which authenticates the log delivery process.

Step 2: Add the Log Drain

Once you have your Atatus log endpoint and API key, you can set up the log drain in your Heroku app using the Heroku CLI.

Run the following command:

heroku drains:add https://<your-atatus-ingestion-endpoint>?apikey=<your-api-key>

This command tells Heroku to start sending logs to your Atatus account, where they can be analyzed and visualized.

Step 3: Verify Log Flow in Atatus

Once the log drain is configured, logs will start flowing into Atatus. You can go to your Atatus dashboard and check the Logs section to ensure that logs are being received. In Atatus, you can search through your logs, create custom queries, and set up alerts based on log patterns.

Managing Heroku Logs: Best Practices

To effectively manage and optimize your Heroku logs, it's important to implement strategies for retention, filtering, organization, and analysis. Here are some of the best practices to keep your logs efficient.

Log Retention Policies: Logs can quickly accumulate, so it's important to set retention policies to avoid overloading your log management system and incurring unnecessary costs. Heroku allows you to store logs for a limited period of time. For long-term log storage and detailed analysis, forward logs to an external system like Atatus.
Log Filtering: You can filter logs at the application level to ensure that only relevant logs are forwarded to external services. This can help reduce noise and focus on critical events such as errors, performance issues, or unusual activities.
Tagging Logs: Tagging logs with additional metadata (like environment, region, or app name) is a great way to organize logs and make them more searchable. This is especially helpful when you're managing multiple apps or environments.
Analyzing Logs in Context: One of the most powerful features of an observability tool like Atatus is the ability to correlate logs with other performance data, such as metrics and traces. This enables you to get a full picture of your application's health and quickly identify root causes of issues.

Conclusion

Heroku’s Logplex and log drains provide a flexible and scalable logging solution for modern applications. By forwarding logs to an external service like Atatus, you can unlock powerful features such as real-time log monitoring, advanced querying, and visualizations, making it easier to identify and resolve issues quickly. With Logplex’s real-time delivery and Atatus’s observability platform, you can ensure that your application is running smoothly and that you are always on top of critical events.

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