gostatsd

An implementation of Etsy's statsd in Go, based on original code from @kisielk.

The project provides both a server called "gostatsd" which works much like Etsy's version, but also provides a library for developing customized servers.

Backends are pluggable and only need to support the backend interface.

Being written in Go, it is able to use all cores which makes it easy to scale up the server based on load. The server can also be run HA and be scaled out, see Load balancing and scaling out.

Building the server

Gostatsd currently targets Go 1.10.2. There are no known hard dependencies in the code beween 1.9 and 1.10.2, but some may be introduced in future.

From the gostatsd directory run make build. The binary will be built in build/bin/<arch>/gostatsd.

You will need to install the build dependencies by running make setup in the gostatsd directory. This must be done before the first build, and again if the dependencies change.

If you are unable to build gostatsd please try running make setup again before reporting a bug.

Running the server

gostatsd --help gives a complete description of available options and their defaults. You can use make run to run the server with just the stdout backend to display info on screen. You can also run through docker by running make run-docker which will use docker-compose to run gostatsd with a graphite backend and a grafana dashboard.

While not generally tested on Windows, it should work. Maximum throughput is likely to be better on a linux system, however.

Configuring backends and cloud providers

Backends and cloud providers are configured using toml, json or yaml configuration file passed via the --config-path flag. For all configuration options see source code of the backends you are interested in. Configuration file might look like this:

[graphite]
	address = "192.168.99.100:2003"

[datadog]
	api_key = "my-secret-key" # Datadog API key required.

[statsdaemon]
	address = "docker.local:8125"
	disable_tags = false

[aws]
	max_retries = 4

Configuring timer sub-metrics

By default, timer metrics will result in aggregated metrics of the form (exact name varies by backend):

<base>.Count
<base>.CountPerSecond
<base>.Mean
<base>.Median
<base>.Lower
<base>.Upper
<base>.StdDev
<base>.Sum
<base>.SumSquares

In addition, the following aggregated metrics will be emitted for each configured percentile:

<base>.Count_XX
<base>.Mean_XX
<base>.Sum_XX
<base>.SumSquares_XX
<base>.Upper_XX - for positive only
<base>.Lower_-XX - for negative only

These can be controlled through the disabled-sub-metrics configuration section:

[disabled-sub-metrics]
# Regular metrics
count=false
count-per-second=false
mean=false
median=false
lower=false
upper=false
stddev=false
sum=false
sum-squares=false

# Percentile metrics
count-pct=false
mean-pct=false
sum-pct=false
sum-squares-pct=false
lower-pct=false
upper-pct=false

By default (for compatibility), they are all false and the metrics will be emitted.

Sending metrics

The server listens for UDP packets on the address given by the --metrics-addr flag, aggregates them, then sends them to the backend servers given by the --backends flag (space separated list of backend names).

Currently supported backends are:

graphite
datadog
statsdaemon
stdout
cloudwatch

The format of each metric is:

<bucket name>:<value>|<type>\n

<bucket name> is a string like abc.def.g, just like a graphite bucket name
<value> is a string representation of a floating point number
<type> is one of c, g, or ms for "counter", "gauge", and "timer" respectively.

A single packet can contain multiple metrics, each ending with a newline.

Optionally, gostatsd supports sample rates (for simple counters, and for timer counters) and tags (unused):

<bucket name>:<value>|c|@<sample rate>\n where sample rate is a float between 0 and 1
<bucket name>:<value>|c|@<sample rate>|#<tags>\n where tags is a comma separated list of tags
or <bucket name>:<value>|<type>|#<tags>\n where tags is a comma separated list of tags

Tags format is: simple or key:value.

A simple way to test your installation or send metrics from a script is to use echo and the netcat utility nc:

echo 'abc.def.g:10|c' | nc -w1 -u localhost 8125

Monitoring

Many metrics for the internal processes are emitted. See METRICS.md for details. Go expvar is also exposed if the --profile flag is used.

Memory allocation for read buffers

By default gostatsd will batch read multiple packets to optimise read performance. The amount of memory allocated for these read buffers is determined by the config options:

max-readers * receive-batch-size * 64KB (max packet size)

The metric avg_packets_in_batch can be used to track the average number of datagrams received per batch, and the --receive-batch-size flag used to tune it. There may be some benefit to tuning the --max-readers flag as well.

Using the library

In your source code:

import "github.com/atlassian/gostatsd/pkg/statsd"

Documentation can be found via go doc github.com/atlassian/gostatsd/pkg/statsd or at https://godoc.org/github.com/atlassian/gostatsd/pkg/statsd

Contributors

Pull requests, issues and comments welcome. For pull requests:

Add tests for new features and bug fixes
Follow the existing style
Separate unrelated changes into multiple pull requests

See the existing issues for things to start contributing.

For bigger changes, make sure you start a discussion first by creating an issue and explaining the intended change.

Atlassian requires contributors to sign a Contributor License Agreement, known as a CLA. This serves as a record stating that the contributor is entitled to contribute the code/documentation/translation to the project and is willing to have it used in distributions and derivative works (or is willing to transfer ownership).

Prior to accepting your contributions we ask that you please follow the appropriate link below to digitally sign the CLA. The Corporate CLA is for those who are contributing as a member of an organization and the individual CLA is for those contributing as an individual.

License

Licensed under the MIT license. See LICENSE file.

a-kr / gostatsd