ci: bump promci to v0.8.2 and push to GHCR (#309)

Bump promci composite actions to v0.8.2 (pinned by SHA)
Remove standalone actions/checkout steps before promci build/publish steps (promci v0.8.2 performs the checkout itself)
Add packages: write permission to publish_main and publish_release jobs
Add ghcr_io_password: ${{ github.token }} to both publish jobs

Signed-off-by: Julien Pivotto 291750+roidelapluie@users.noreply.github.com

Memcached Exporter for Prometheus

A memcached exporter for Prometheus.

Building

The memcached exporter exports metrics from a memcached server for consumption by Prometheus. The server is specified as --memcached.address flag to the program (default is localhost:11211).

By default the memcache_exporter serves on port 0.0.0.0:9150 at /metrics:

make
./memcached_exporter

Alternatively a Dockerfile is supplied:

docker run -p 9150:9150 quay.io/prometheus/memcached-exporter:latest

Collectors

The exporter collects a number of statistics from the server.

For supported metrics see the metrics documentation.

TLS and basic authentication

The Memcached Exporter supports TLS and basic authentication.

To use TLS and/or basic authentication, you need to pass a configuration file using the --web.config.file parameter. The format of the file is described in the exporter-toolkit repository.

To use TLS for connections to memcached, use the --memcached.tls.* flags. See memcached_exporter --help for details.

Multi-target

The exporter also supports the multi-target pattern on the /scrape endpoint. Example:

curl `localhost:9150/scrape?target=memcached-host.company.com:11211

An example configuration using prometheus-elasticache-sd:

scrape_configs:
  - job_name: "memcached_exporter_targets"
    file_sd_configs:
    - files:
        - /path/to/elasticache.json  # File created by service discovery
    metrics_path: /scrape
    relabel_configs:
      # Filter for memcached cache nodes
      - source_labels: [__meta_elasticache_engine]
        regex: memcached
        action: keep
      # Build Memcached URL to use as target parameter for the exporter
      - source_labels:
          - __meta_elasticache_endpoint_address
          - __meta_elasticache_endpoint_port
        replacement: $1
        separator: ':'
        target_label: __param_target
      # Use Memcached URL as instance label
      - source_labels: [__param_target]
        target_label: instance
      # Set exporter address
      - target_label: __address__
        replacement: memcached-exporter-service.company.com:9151

If you are running solely for multi-target start the exporter with --memcached.address="" to avoid attempting to connect to a non existing memcached host, example:

./memcached-exporter --memcached.address=""