The Service Map for APM is here!

Heroku Buildpack

This buildpack installs the Datadog Agent in your Heroku Dyno to collect system metrics, custom application metrics, and traces. To collect custom application metrics or traces, include the language appropriate DogStatsD or Datadog APM library in your application.


To add this buildpack to your project, as well as set the required environment variables:

cd <root of my project>

# If this is a new Heroku project
heroku create

# Add the appropriate language-specific buildpack. For example:
heroku buildpacks:add heroku/ruby

# Enable Heroku Labs Dyno Metadata
heroku labs:enable runtime-dyno-metadata -a $(heroku apps:info|grep ===|cut -d' ' -f2)

# Add this buildpack and set your Datadog API key
heroku buildpacks:add --index 1
heroku config:add DD_API_KEY=<your API key>

# Deploy to Heroku
git push heroku master

Once complete, the Datadog Agent is started automatically when each Dyno starts.

The Datadog Agent provides a listening port on 8125 for StatsD/DogStatsD metrics and events. Traces are collected on port 8126.


In addition to the environment variables shown above, there are a number of others available:

Setting Description
DD_API_KEY Required. Your API key is available from the Datadog API Integrations page. Note that this is the API key, not the application key.
DD_HOSTNAME Deprecated. WARNING: Setting the hostname manually may result in metrics continuity errors. It is recommended that you do not set this variable. Because dyno hosts are ephemeral it is recommended that you monitor based on the tags dynoname or appname.
DD_DYNO_HOST Optional. Set to true to use the dyno name (e.g. web.1 or run.1234) as the hostname. See the hostname section below for more information. Defaults to false.
DD_TAGS Optional. Sets additional tags provided as a space-delimited string. For example, heroku config:set DD_TAGS="simple-tag-0 tag-key-1:tag-value-1". The buildpack automatically adds the tags dyno and dynohost which represent the Dyno name (e.g. web.1) and host ID (e.g. 33f232db-7fa7-461e-b623-18e60944f44f) respectively. See the “Guide to tagging” for more information.
DD_HISTOGRAM_PERCENTILES Optional. Optionally set additional percentiles for your histogram metrics. See How to graph percentiles.
DISABLE_DATADOG_AGENT Optional. When set, the Datadog Agent does not run.
DD_APM_ENABLED Optional. Trace collection is enabled by default. Set this to false to disable trace collection.
DD_AGENT_VERSION Optional. By default, the buildpack installs the latest version of the Datadog Agent available in the package repository. Use this variable to install older versions of the Datadog Agent (note that not all versions of the Agent may be available).
DD_SERVICE_ENV Optional. The Datadog Agent automatically tries to identify your environment by searching for a tag in the form env:<environment name>. For more information, see the Datadog Tracing environments page.


Heroku dynos are ephemeral-they can move to different host machines whenever new code is deployed, configuration changes are made, or resouce needs/availability changes. This makes Heroku flexible and responsive, but can potentially lead to a high number of reported hosts in Datadog. Datadog bills on a per-host basis, and the buildpack default is to report actual hosts, which can lead to higher than expected costs.

Depending on your use case, you may want to set your hostname so that hosts are aggregated and report a lower number. To do this, Set DD_DYNO_HOST to true. This causes the Agent to report the hostname as the dyno name (e.g. web.1 or run.1234), so your host count matches your dyno usage. One drawback is that you may see some metrics continuity errors whenever a dyno is cycled.

Files Locations

  • The Datadog Agent is installed at /app/.apt/opt/datadog-agent
  • The Datadog Agent configuration files are at /app/.apt/etc/datadog-agent
  • The Datadog Agent logs are at /app/.apt/var/log/datadog

Heroku Log Collection

This log integration is currently in public beta

Heroku provides 3 types of logs:

  • App Logs: output from the application you pushed on the platform.
  • System Logs: messages about actions taken by the Heroku platform infrastructure on behalf of your app.
  • API Logs: administrative questions implemented by you and other developers working on your app.

Heroku’s HTTP/S 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.
The Datadog HTTP API implements and understands the Logplex standard defined by the content-header application/logplex-1.

To send all these logs to Datadog:

  • Connect to your Heroku project.
  • Set up the HTTPS drain with the following command:
heroku drains:add<DD_API_KEY>?ddsource=heroku&service=<SERVICE>&host=<HOST> -a <APPLICATION_NAME>
heroku drains:add<DD_API_KEY>?ddsource=heroku&service=<SERVICE>&host=<HOST> -a <APPLICATION_NAME>
  • Replace <DD_API_KEY> with your Datadog API Key.
  • Replace <APPLICATION_NAME> and <SERVICE> with your application name.
  • Replace <HOST> with the desired hostname. Note: Per the host section, metrics and traces set the default host name to the dyno name. It is not yet possible to dynamically set the dyno name as the hostname for logs. For now, to correlate between metrics, traces, and logs the dyno and dynotype tags can be used.

Custom attributes

Add custom attributes to logs from your application by replacing the URL in the drain as follows:<DD_API_KEY>?ddsource=heroku&service=<SERVICE>&host=<HOST>&attribute_name=<VALUE><DD_API_KEY>?ddsource=heroku&service=<SERVICE>&host=<HOST>&attribute_name=<VALUE>


Verify the Datadog Agent is listening by sending a custom metric:

# From your project directory:
heroku run bash

# Once your Dyno has started and you are at the command line
echo -n "custom_metric:60|g|#shell" >/dev/udp/localhost/8125

After a few moments, use the metrics explorer to verify that the metric was received.

It can also be helpful to obtain Agent and Trace Agent logs from your running dyno.

Download Datadog Agent logs:

heroku ps:copy /app/.apt/var/log/datadog/datadog.log --dyno=<YOUR DYNO NAME>

Download Datadog Trace Agent logs:

heroku ps:copy /app/.apt/var/log/datadog/datadog-apm.log --dyno=<YOUR DYNO NAME>

Send a flare

Generate a flare by running:

# From your project directory:
heroku run bash

# Once your Dyno has started and you are at the command line, send a flare:
agent -c /app/.apt/etc/datadog-agent/datadog.yaml flare

The flare contains the environment information and Datadog Agent configuration. However, since this is a new, stand-alone dyno, the logs are sparse and may not contain full log information.

Generate a more complete flare by setting your API key as an environment variable by running:

heroku ps:exec
agent -c /app/.apt/etc/datadog-agent/datadog.yaml flare

More information

Visit the Github project page for more information and to view the source code.