Metrics

This module enables prometheus metrics for Casket.

(Forked from https://github.com/miekg/caddy-prometheus)

Use

In your Casketfile:

prometheus

For each virtual host that you want to see metrics for.

These are the (optional) parameters that can be used:

• use_casket_addr - causes metrics to be exposed at the same address:port as Casket itself. This can not be specified at the same time as address.
• address - the address where the metrics are exposed, the default is localhost:9180
• path - the path to serve collected metrics from, the default is /metrics
• hostname - the host parameter that can be found in the exported metrics, this defaults to the label specified for the server block
• label - Custom label to add on all metrics. This directive can be used multiple times. You should specify a label name and a value. The value is a placeholder and can be used to extract value from response header for instance. Usage: label route_name {<X-Route-Name}

With casketext you'll need to put this module early in the chain, so that the duration histogram actually makes sense. I've put it at number 0.

Metrics

The following metrics are exported:

• casket_http_request_count_total{host, family, proto}
• casket_http_request_duration_seconds{host, family, proto}
• casket_http_response_latency_seconds{host, family, proto, status}
• casket_http_response_size_bytes{host, family, proto, status}
• casket_http_response_status_count_total{host, family, proto, status}

Each metric has the following labels:

• host which is the hostname used for the request/response,
• family which is the protocol family, either 1 (IP version 4) or 2 (IP version 6),
• proto which is the HTTP protocol major and minor version used: 1.x or 2 signifying HTTP/1.x or HTTP/2.

The response_* metrics have an extra label status which holds the status code.