Funnel metrics from multiple Heroku apps into DataDog using statsd.
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.

wercker status Build Status

Heroku Datadog Drain

Golang version of NodeJS

Funnel metrics from multiple Heroku apps into DataDog using statsd.

Supported Heroku metrics:

  • Heroku Router response times, status codes, etc.
  • Application errors
  • Custom metrics
  • Heroku Dyno runtime metrics
  • (beta) Heroku Runtime Language Metrics - we add support for golang used in Heroku, next step add this to send to Datadog too for self monitoring app.

Get Started

Clone the Github repository

git clone
cd heroku-datadog-drain-golang

Setup Heroku, specify the app(s) you'll be monitoring and create a password for each.

heroku create
heroku config:set ALLOWED_APPS=<your-app-slug> <YOUR-APP-SLUG>_PASSWORD=<password>

OPTIONAL: Setup Heroku build packs, including the Datadog DogStatsD client. If you already have a StatsD client running, see the STATSD_URL configuration option below.

heroku buildpacks:add heroku/go
heroku buildpacks:add --index 1
heroku config:set HEROKU_APP_NAME=$(heroku apps:info|grep ===|cut -d' ' -f2)
heroku config:add DATADOG_API_KEY=<your-Datadog-API-key>

Don't forget set right golang version.

heroku config:add GOVERSION=go1.9

Deploy to Heroku.

git push heroku master
heroku ps:scale web=1

Add the Heroku log drain using the app slug and password created above.

heroku drains:add https://<your-app-slug>:<password>@<this-log-drain-app-slug> --app <your-app-slug>


STATSD_URL=..             # Required. Set to: localhost:8125
DATADOG_API_KEY=...       # Required. Datadog API Key -
ALLOWED_APPS=my-app,..    # Required. Comma seperated list of app names
<APP-NAME>_PASSWORD=..    # Required. One per allowed app where <APP-NAME> corresponds to an app name from ALLOWED_APPS
<APP-NAME>_TAGS=mytag,..  # Optional. Comma seperated list of default tags for each app
<APP-NAME>_PREFIX=..      # Optional. String to be prepended to all metrics from a given app
DATADOG_DRAIN_DEBUG=..    # Optional. If DEBUG is set, a lot of stuff will be logged :)
EXCLUDED_TAGS: path,host  # Optional. Recommended to solve problem with tags limit (1000)

Note that the capitalized <APP-NAME> and <YOUR-APP-SLUG> appearing above indicate that your application name and slug should also be in full caps. For example, to set the password for an application named my-app, you would need to specify heroku config:set ALLOWED_APPS=my-app MY-APP_PASSWORD=example_password

The rationale for EXCLUDED_TAGS is that the path= tag in Heroku logs includes the full HTTP path - including, for instance, query parameters. This makes very easy to swarm Datadog with numerous distinct tag/value pairs; and Datadog has a hard limit of 1000 such distinct pairs. When the limit is breached, they blacklist the entire metric.

Heroku settings

You need use Standard dynos and better and enable log-runtime-metrics in heroku labs for every application.

heroku labs:enable log-runtime-metrics -a APP_NAME

This adds basic metrics (cpu, memory etc.) into logs.

Custom Metrics

If you want to log some custom metrics just format the log line like following:

app web.1 - info: responseLogger: metric#tag#route=/parser metric#request_id=11747467-f4ce-4b06-8c99-92be968a02e3 metric#request_length=541 metric#response_length=5163 metric#parser_time=5ms metric#eventLoop.count=606 metric#eventLoop.avg_ms=515.503300330033 metric#eventLoop.p50_ms=0.8805309734513275 metric#eventLoop.p95_ms=3457.206896551724 metric#eventLoop.p99_ms=3457.206896551724 metric#eventLoop.max_ms=5008

We support:

  • metric# and sample# for gauges
  • metric#tag for tags.
  • count# for counter increments
  • measure# for histograms

more info here

Overriding prefix and tags with drain query params

To change the prefix use the drain of form: https://<your-app-slug>:<password>@<this-log-drain-app-slug>

To change tags use the drain of form: https://<your-app-slug>:<password>@<this-log-drain-app-slug>,abcd