---
title: "Heroku Logs"
description: "Set up Middleware integration with Heroku log drains to track logs, monitor app health, and detect errors efficiently."
section: "Integrations"
breadcrumb: "Integrations > Hosting Platforms > Heroku Logs"
canonical: "https://docs.middleware.io/integrations/heroku-log-drains"
---
# Heroku Log Drains

Heroku’s HTTP/S [log drains](https://devcenter.heroku.com/articles/log-drains) buffer log messages and submit batches of messages to an HTTPS endpoint via a POST request. The POST body contains Syslog formatted messages, framed using the Syslog TCP protocol octet counting framing method.

Middleware’s HTTP API implements and understands the Logplex standard defined by the content-header `application/logplex-1`.

To setup HTTP/S log drains with Middleware, first setup `APPNAME`, `SERVICE` and `MW_API_KEY` environment variable:

```Shell
export MW_API_KEY=your-initial-token
export APPNAME=<YOUR_HEROKU_APPNAME>
export SERVICE=<SERVICE_NAME>
```

- Replace `<MW_API_KEY>` with your Middleware API Key.
- Replace `<YOUR_HEROKU_APPNAME>` with the the Heroku application name you want to enable log drains for.
- Replace `<SERVICE_NAME>` with something that represents the service for your Heroku application. For example, if your Heroku application is called `payment-gateway`, your `SERVICE` name could be `billing-service`.

> **Note:** Providing relevant values for `APPNAME` and `SERVICE` makes it easier to filter logs inside of the Middleware Platform.

Then configure the log drain using the following command:

```Shell
heroku drains:add "your-initial-uid/v1/integrations/heroku/logs?mw-api-key=$MW_API_KEY&app=$APPNAME&service=$SERVICE" -a $APPNAME
```

- Replace `<MW_UID>` with your Middleware account ID.

## Heroku Log Categories

Heroku provides three categories of logs for a deployed application:

- **App Logs**: These are the logs from your deployed application.
- **API Logs**: These are the audit logs on administrative actions executed by you and other developers working on your application.
- **System Logs**: These are the logs about actions taken by the Heroku platform infrastructure on behalf of your application.

Middleware collects all three categories of logs and creates attributes for them to make filtering easier and consistent. Below are some rules about the attributes collected:

- If `app` name parameter is not provided, the default `app` name is set to `herokuapp`.
- If `source` parameter is not provided, the default `source` is set to `heroku`.
- If `service` parameter is not provided, the `app` parameter value is used as a `service.name`.
- If both `service` and `app` attributes are not set, the default `service.name` is set to `heroku`.

## App & API Logs Specific Attributes

For `App` & `API` category logs, the `host.name` attribute is added by combining the `app` name query query parameter value passed in the drain URL and the `syslog.proc.id` attribute value.

Heroku provides Syslog process ID as the Dyno ID.  For example, if `app` name is `billing-app` and Syslog process ID is `web.1234`, `host.name` will be set to `billing-app.web.1234`.

All other attributes are parsed from Syslog formatted message metadata.

## System Log Specific Attributes

For `System` category Logs, the `host.name` attribute is added by combining the `app` name query parameter value passed in the drain URL and `dyno` field from the message body itself. For example, if `app` name is `billing-app` and the `dyno` field is `web.1234`, `host.name` will be set to `billing-app.web.1234`.

`dyno` and `dyno.type` attributes are added by parsing relevant fields from the message body.

All other attributes are parsed from Syslog formatted message metadata and body.

> **Note:** Attributes added by Middleware make it easier to co-relate Heroku logs and metrics.
>
> For example, using the same value for the `MW_DYNO_HOSTNAME` environment variable in the [Heroku buildpack for Middleware](/get-started/agent/heroku) and the `app` name query parameter in the log drains URL above makes it easier to correlate logs and metrics from the same host.

## Custom attributes:

You can add custom attributes to your logs by adding query parameters in the URL of the drain command as follows:

```Shell
heroku drains:add "your-initial-uid/v1/integrations/heroku/logs?my-attribute=my-value&mw-api-key=your-initial-token&app=$APPNAME&service=$SERVICE" -a $APPNAME
```

In the above command, `my-attribute` in query parameter is the custom attribute and `my-value` is the value for that attribute.