Background

Folsom is an Erlang-based application that can collect realtime metrics and publish them. More details can be found at:

https://github.com/boundary/folsom <https://github.com/boundary/folsom>

This CloudI service allows other CloudI services to define new Folsom metrics, update those metrics, and get the current metric values.

Usage

Service Configuration

An example configuration is shown below: [{type, internal}, {prefix, "/folsom/"}, {module, cloudi_service_folsom}, {args, []}, {dest_refresh, immediate_random}, {timeout_init, 60000}, {timeout_async, 60000}, {timeout_sync, 60000}, {dest_list_deny, undefined}, {dest_list_allow, undefined}, {count_process, 1}, {max_r, 5}, {max_t, 900}, {options, [{reload, true}, {queue_limit, 500}]} ]

Service Patterns

This service subscribes to the following request patterns: /metrics /metric_value?metric_name /new_counter?metric_name /notify?update_value where update value is of the form {metric_name, value} or {metric_name, {inc, value}} or {metric_name, {dec, value}}

Examples using HTTP requests

The following examples use the Curl command to execute an HTTP request

define the HTTP endpoint

export FOLSOM_HTTP=http://localhost:6467/folsom

Get list of metrics

curl $FOLSOM_HTTP/metrics

Add a new counter metric

curl $FOLSOM_HTTP/new_counter?test_requests

Get the current value of the counter

curl $FOLSOM_HTTP/metric_value?test_requests

Update the counter value

Note the use of the curl encoding feature to properly format the request

curl -G $FOLSOM_HTTP/notify --data-urlencode "{test_requests, {inc,1}}"