OpenVPN AS metrics exporter for Prometheus

A Prometheus exporter that makes calls to the XML-RPC unix domain socket exposed by the OpenVPN AS service, and generates metrics from the responses.

Current metrics include:

• Server status
  • Server version
  • Number of connected clients and max allowed concurrect connections
• Subscription status
  • Number of current and maximum concurrent connections
  • Subscription last successful sync and next update sync timestamp

Based on openvpnas-exporter.

Exposed metrics example

# HELP openvpnas_build_info A metric with a constant '1' value labeled by version, revision, branch, goversion from which openvpnas was build, and the goos and goarch for the build.
# TYPE openvpnas_build_info gauge
openvpnas_build_info{branch="",goarch="amd64",goos="linux",goversion="go1.21.1",revision="unknown",tags="unknown",version="(devel)"} 1
# HELP openvpnas_server_connected_clients Number of currently connected clients to the server.
# TYPE openvpnas_server_connected_clients gauge
openvpnas_server_connected_clients 1
# HELP openvpnas_server_connected_clients_limit Server concurrent client connection limit.
# TYPE openvpnas_server_connected_clients_limit gauge
openvpnas_server_connected_clients_limit 10
# HELP openvpnas_server_version_info Contains OpenVPN AS server version info
# TYPE openvpnas_server_version_info gauge
openvpnas_server_version_info{version="2.12.3 (build 76774795)"} 1
# HELP openvpnas_subscription_connected_clients Total number of client connections currently in use across the OpenVPN AS subscription.
# TYPE openvpnas_subscription_connected_clients gauge
openvpnas_subscription_connected_clients 3
# HELP openvpnas_subscription_connected_clients_limit Maximum number of concurrent client connections allowed by the OpenVPN AS subscription.
# TYPE openvpnas_subscription_connected_clients_limit gauge
openvpnas_subscription_connected_clients_limit 10
# HELP openvpnas_subscription_status_last_update_time_seconds UNIX timestamp when the OpenVPN AS subscription was last synced.
# TYPE openvpnas_subscription_status_last_update_time_seconds gauge
openvpnas_subscription_status_last_update_time_seconds 1.708366094e+09
# HELP openvpnas_subscription_status_next_update_time_seconds UNIX timestamp of the next planned OpenVPN AS subscription sync.
# TYPE openvpnas_subscription_status_next_update_time_seconds gauge
openvpnas_subscription_status_next_update_time_seconds 1.708366294e+09
# HELP openvpnas_up Whether scaping OpenVPN AS metrics was successful.
# TYPE openvpnas_up gauge
openvpnas_up 1

Usage

usage: openvpnas_exporter [<flags>]


Flags:
  --[no-]help                   Show context-sensitive help (also try --help-long and --help-man).
  --web.listen-address=":9176"  Address to listen on for web interface and telemetry.
  --web.telemetry-path="/metrics"  
                                Path under which to expose metrics.
  --openvpnas.xmlrpc-path="/usr/local/openvpn_as/etc/sock/sagent.localroot"  
                                Path to the XML-RPC unix domain socket file.
  --[no-]version                Show application version.

By default the socket file is owned by root so you probably need to run the exporter as root (for now).

Get a standalone executable binary

You can download the pre-compiled binaries from the releases page.

Contributions/development

Please run gofmt on your code to fix formatting/styling, ie. gofmt -w . to recursively fix all formatting in the repository.

Dependencies

Go is fairly smart about this, if you add a import to a program and run go build path/to/main.go it will automatically update go.mod.

Still, it is a good idea to run go mod tidy before committing your changes, this will ensure go.mod and go.sum are in order.

Commit messages

If you want your changes to show up properly in the release notes, prefix your commit messages with:

• build
• doc
• feat
• fix
• sec

Eg.

feat: add openvpnas_up gauge

See .changelog.groups in .goreleaser for details / full regex.

Releases

To make a new release you need to create a new tag in the semver format, ie tag name will look something like v0.0.1.

git checkout master
git tag -a v0.0.1 -m "My message (not shown anywhere)"
git push origin v0.0.1