Zipkin

Propagate Zipkin distributed tracing spans, and report spans to a Zipkin server.

Terminology

• plugin: a plugin executing actions inside Kong before or after a request has been proxied to the upstream API.
• Service: the Kong entity representing an external upstream API or microservice.
• Route: the Kong entity representing a way to map downstream requests to upstream services.
• Consumer: the Kong entity representing a developer or machine using the API. When using Kong, a Consumer only communicates with Kong which proxies every call to the said upstream API.
• Credential: a unique string associated with a Consumer, also referred to as an API key.
• upstream service: this refers to your own API/service sitting behind Kong, to which client requests are forwarded.
• API: a legacy entity used to represent your upstream services. Deprecated in favor of Services since CE 0.13.0 and EE 0.32.

Configuration

Enabling the plugin on a Service

Configure this plugin on a Service by making the following request:

$ curl -X POST http://kong:8001/services/{service}/plugins \
    --data "name=zipkin"  \
    --data "config.http_endpoint=http://your.zipkin.collector:9411/api/v2/spans" \
    --data "config.sample_ratio=0.001"

• service: the id or name of the Service that this plugin configuration will target.

Enabling the plugin on a Route

Configure this plugin on a Route with:

$ curl -X POST http://kong:8001/routes/{route_id}/plugins \
    --data "name=zipkin"  \
    --data "config.http_endpoint=http://your.zipkin.collector:9411/api/v2/spans" \
    --data "config.sample_ratio=0.001"

• route_id: the id of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

You can use the http://localhost:8001/plugins endpoint to enable this plugin on specific Consumers:

$ curl -X POST http://kong:8001/plugins \
    --data "name=zipkin" \
    --data "consumer_id={consumer_id}"  \
    --data "config.http_endpoint=http://your.zipkin.collector:9411/api/v2/spans" \
    --data "config.sample_ratio=0.001"

Where consumer_id is the id of the Consumer we want to associate with this plugin.

You can combine consumer_id and service_id

in the same request, to furthermore narrow the scope of the plugin.

Enabling the plugin on an API

If you are using an older version of Kong with the legacy API entity (deprecated in favor of Services since CE 0.13.0 and EE 0.32.), you can configure this plugin on top of such an API by making the following request:

$ curl -X POST http://kong:8001/apis/{api}/plugins \
    --data "name=zipkin"  \
    --data "config.http_endpoint=http://your.zipkin.collector:9411/api/v2/spans" \
    --data "config.sample_ratio=0.001"

• api: either id or name of the API that this plugin configuration will target.

Global plugins

All plugins can be configured using the http://kong:8001/plugins/ endpoint. A plugin which is not associated to any Service, Route or Consumer (or API, if you are using an older version of Kong) is considered "global", and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

How it Works

When enabled, this plugin traces requests in a way compatible with zipkin.

The code is structured around an opentracing core using the opentracing-lua library to collect timing data of a request in each of Kong’s phases. The plugin uses opentracing-lua compatible extractor, injector, and reporters to implement Zipkin’s protocols.

Extractor and Injector

An opentracing “extractor” collects information from an incoming request. If no trace ID is present in the incoming request, then one is probabilistically generated based on the sample_ratio configuration value.

An opentracing “injector” adds trace information to an outgoing request. Currently, the injector is only called for the request proxied by kong; it is not yet used for requests to the database or by other plugins (such as the http-log plugin).

This plugin follows Zipkin’s “B3” specification as to which HTTP headers to use. Additionally, it supports Jaegar-style uberctx- headers for propagating baggage.

Reporter

An opentracing “reporter” is how tracing data is reported to another system. This plugin records tracing data for a given request, and sends it as a batch to a Zipkin server using the Zipkin v2 API. Note that zipkin version 1.31 or higher is required.

The http_endpoint configuration variable must contain the full uri including scheme, host, port and path sections (i.e. your uri likely ends in /api/v2/spans).

FAQ

Can I use this plugin with other tracing systems, like Jaeger?

Probably! Jaeger accepts spans in Zipkin format - see https://www.jaegertracing.io/docs/features/#backwards-compatibility-with-zipkin for more information.