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Prometheus metric event handlers

Metric updates are generally carried out inside event handlers. By overwriting these handlers, users can update metric values in response to various triggers ranging from HTTP requests to timer events.

The functions outlined below can be modified to allow a user to monitor events outside those exposed in exporter.q

.prom. event handlers
on_poll Prometheus poll request
on_pc IPC socket connection closing
on_po IPC socket connection opening
on_wc Websocket connection closing
on_wo Websocket connection opening
after_pg Synchronous IPC socket request handler, call after execution
before_pg Synchronous IPC socket request handler, call before execution
after_ps Asynchronous IPC socket request handler, call after execution
before_ps Asynchronous IPC socket request handler, call before execution
after_ph HTTP GET request handler, call after execution
before_ph HTTP GET request handler, call before execution
after_pp HTTP POST request handler, call after execution
before_pp HTTP POST request handler, call before execution
after_ws Websocket request handler, call after execution
before_ws Websocket request handler, call before execution
after_ts Timer event handler, call after execution
before_ts Timer event handler, call after execution

👉 Example invocations of these event handlers

Once the relevant event handlers have been defined to update the metric values, initialize the library with a call to .prom.init

⚠️ Updating .z.* handlers after the call to .prom.init will overwrite the Prometheus logic. Correct usage is to load all process logic before loading the Prometheus library.

.prom.after_pg

Synchronous IPC socket request handler, called after execution

.prom.after_pg[tmp;msg;res]

Where

  • tmp is the object returned by .prom.before_pg
  • msg is the object that was executed
  • res is the object returned by the execution of msg

.prom.after_ph

HTTP GET request handler, called after execution

.prom.after_ph[tmp;(requestText;requestHeaderAsDictionary);res]

Where

  • tmp is the object returned by .prom.before_ph
  • (requestText;requestHeaderAsDictionary) is a HTTP GET request
  • res is the object returned by the execution of msg

.prom.after_pp

HTTP POST request handler, called after execution

.prom.after_pp[tmp;(requestText;requestHeaderAsDictionary);res]

Where

  • tmp is the object returned by .prom.before_pp
  • (requestText;requestHeaderAsDictionary) is a HTTP POST request
  • res is the object returned by the execution of msg

.prom.after_ps

Asynchronous IPC socket request handler, called after execution

.prom.after_ps[tmp;msg;res]

Where

  • tmp is the object returned by .prom.before_ps
  • msg is the object that was executed
  • res is the object returned by the execution of msg

.prom.after_ts

Timer event handler, called after execution

.prom.after_ts[tmp;dtm;res]

Where

  • tmp is the object returned by .prom.before_ts
  • dtm is the timestamp at the start of execution
  • res is the object returned by the execution of dtm

.prom.after_ws

Websocket request handler, called after execution

.prom.after_ws[tmp;msg;res]

Where

  • tmp is the object returned by .prom.before_ws
  • msg is the object that was executed
  • res is the object returned by the execution of msg

.prom.before_pg

Synchronous IPC socket request handler, called before execution

.prom.before_pg msg

Where msg is the object to be executed, returns a tmp object to be passed to the after handler.

.prom.before_ph

HTTP GET request handler, called before execution

.prom.before_ph(requestText;requestHeaderAsDictionary)

Where (requestText;requestHeaderAsDictionary) is an HTTP GET request, returns a tmp object to be passed to the after handler.

.prom.before_pp

HTTP POST request handler, called before execution

.prom.before_pp(requestText;requestHeaderAsDictionary)

Where (requestText;requestHeaderAsDictionary) is an HTTP POST request, returns a tmp object to be passed to the after handler.

.prom.before_ps

Asynchronous IPC socket request handler, called before execution

.prom.before_ps msg

Where msg is the object to be executed, returns a tmp object to be passed to the after handler.

.prom.before_ts

Timer event handler, called before execution

.prom.before_ts dtm

Where dtm is the timestamp at the start of execution, returns a tmp object to be passed to the after handler.

.prom.before_ws

Websocket request handler, called before execution

.prom.before_ws msg

Where msg is the object to be executed, returns a tmp object to be passed to the after handler.

.prom.on_pc

Socket close handler

.prom.on_pc hdl

Where hdl is the handle of a socket connection, closes the socket.

.prom.on_po

Socket open handler

.prom.on_po hdl

Where hdl is the handle of a socket connection, opens the socket.

.prom.on_poll

Prometheus poll request handler

.prom.on_poll(requestText;requestHeaderAsDictionary)

Where (requestText;requestHeaderAsDictionary) is an HTTP request