nc prometheus exporter

Nc prometheus exporter is a little webserver, which translates the nextcloud status xml to a prometheus compatible format.

Usage

NCE_CONF=nc_prometheus_exporter.conf nc_prometheus_exporter

Environment

key	description	default
NCE_CONF	Path to configuration file	/etc/ncexporter/nc_prometheus_exporter.conf
NCE_PORT	tcp port	8000
RUST_LOG	Rust log level	warn

Nextcloud endpoint configuration

key	description
nc_url	Url of a nextcloud instance
nc_user	Username of an admin user
nc_password	App password of the admin user
nc_replacement_config	Path to replacement config (json)

Example configuration

nc_url = 'https://your.domain.tld/ocs/v2.php/apps/serverinfo/api/v1/info'
nc_user = 'example_user'
nc_password = 'example_pw'
nc_replacement_config = 'replacements.json'

Hint: Create and use a device password (Nextcloud documentation)

Replacement configuration

The json replacement configuration defines how to replace values during translations. Some Nextcloud info values are not numeric, and therefore not compatible with prometheus. Values will be ignored if not numeric and no string to numeric replacement pair is defined.

Ignored metrics will be displayed via logging output on log level debug.

Example configuration

{
    "values" : {
        "ok": 1,
        "yes": 1,
        "OK": 1,
        "none": 0,
        "no": 0
    }
}

Translation process

After fetching the xml status information from a nextcloud instance, each entry is processed by the exporter. The xml node names will be combined into a prometheus time series name.

Numeric values will be used as prometheus metric. Non numeric values will be replaced with a numeric value if configured, or otherwise dropped.

Additional to nextcloud metrics a few metrics regarding the export will be added.

Additional exporter metrics

name	description
rust_nce_parse_duration	Time spent parsing the status xml
rust_nce_load_duration	Duration of loading the status xml from the configured nextcloud instance
rust_nce_total_duration	Combined duration of load, parsing and translation
rust_nce_request_start_count	Count of exporter requests
rust_nce_request_end_count	Count of answered exporter requests
nc_metric_names_hash	Fisrst digits of a md5 hash based on a sorted list of metric names. A change indicates fewer, swapped or additional metrics.