keepup

A lightweight Prometheus exporter that collects infrastructure inventory pushed by remote agents - package versions (with end-of-life enrichment) and Kubernetes/Helm deployments - and exposes it as metrics.

keepup holds no state of its own: Redis is both the write buffer and the read source. Agents PUT JSON, keepup validates and stores it with a TTL, and Prometheus scrapes /metrics on demand.

Contents

• How it works
• Quick start
• Configuration
• API
  • PUT /package-version
  • PUT /helm-cluster
• Metrics
• Testing
• Deploying with Helm
• Releasing

How it works

 agent(s)                    keepup                        Prometheus
-----------   PUT + token   ---------------------  scrape  --------------
│ pkg-vers│ --------------->│ handler --> Redis │<---------│ /metrics   |
│ helm    │                 │           (TTL)   │          │            │
-----------                 ---------------------          --------------

Every data domain follows the same shape:

Domain	Endpoint	Redis key	Metric
Package versions	PUT /package-version	SHA1 of {data_center}-{host_ip}-PACKAGE_UUID	package_version_info
Kubernetes / Helm	PUT /helm-cluster	SHA1 of {cluster_name}	kubernetes_cluster_info

On each scrape, the collector SCANs all Redis keys for the domain, deserializes every entry, and emits one Prometheus metric per entity - there is no in-memory cache, so every scrape hits Redis directly.

Package EOL enrichment: every package-version push is checked against endoflife.date, cached in Redis for 7 days under eol_cache:all_packages. Supported packages: redis, memcached, mongodb, mysql, rabbitmq, envoy, debian, postgresql, elasticsearch, php. Versions are compared as major.minor only (Debian epoch prefixes like 5:7.0.15-1~deb12u1 are stripped down to 7.0).

Quick start

Requires Go and a local Redis instance.

# run locally - must run from src/ so .env is found
cd src && go run main.go

# build a binary
go build -o keepup src/main.go

# build the Docker image
docker build -f docker/Dockerfile -t keepup .

The server listens on LISTEN_PORT (default 9101 in dev) and exposes:

• PUT/GET /package-version, /helm-cluster - data ingestion & lookup (require x-api-token)
• GET /metrics - Prometheus scrape endpoint (no auth)
• GET /healthcheck - liveness probe

Configuration

Config is loaded from environment variables. If APP_ENV is unset, keepup loads src/.env (development only). All fields are required - the app panics at startup if any are missing.

Variable	Default (.env)	Purpose
APP_ENV	dev	when unset, triggers .env loading
API_TOKEN	secret	value required in the x-api-token header on every PUT/GET
LISTEN_PORT	9101	HTTP listen port
REDIS_ADDR	127.0.0.1	Redis host
REDIS_PORT	6379	Redis port
REDIS_DBNO	7	Redis logical DB number
TTL_SECONDS	300	expiry for every stored entry

API

All data endpoints require an x-api-token header matching API_TOKEN, and accept both PUT (insert) and GET (lookup by id).

PUT /package-version

{
  "packages": {
    "debian": "11",
    "mongodb": "7.3",
    "redis": "5:7.0.15-1~deb12u1",
    "mysql": "unknown",
    "host_ip": "101.122.418.4",
    "data_center": "aaa",
    "team": "platform"
  }
}

host_ip, data_center, and team are pulled out of the map and stored as entity metadata; every remaining key is treated as a package name -> installed version pair. Each package is enriched with current_version_eof, newest_version, and expired before being persisted.

PUT /helm-cluster

{
  "cluster_name": "minikube",
  "kube_version": "1.29.0",
  "team": "platform",
  "helm_charts": [
    { "chart_name": "redis", "version": "18.1.5", "namespace": "database" },
    { "chart_name": "keepup", "version": "0.5.0", "namespace": "monitoring" }
  ]
}

Unlike the other two endpoints, the request body maps directly onto the stored struct (no wrapper key, no field filtering).

Metrics

Metric	Labels
package_version_info	id, package_name, current_version, current_version_eof, newest_version, expired, data_center, host_ip, team
kubernetes_cluster_info	id, cluster_name, kube_version, chart_name, chart_version, chart_namespace, team

Testing

Unit tests cover the handler package against an in-process fake Redis (miniredis) - no external services required:

go test ./...

An end-to-end shell script also exercises both endpoints against a running server:

# start the server first (see Quick start), then:
cd tests/end-to-end && ./run.sh

Deploying with Helm

charts/keepup/ deploys keepup with a Redis sidecar in the same pod (redis.enabled: true by default, so no external Redis is required). Key values:

• apiToken - auth token agents must send
• ttlSeconds - entry expiry
• ingress.* - expose the API externally
• servicemonitor.enabled - wire up Prometheus scraping automatically

helm install keepup charts/keepup --set apiToken=<your-token>

Releasing

Pushing a git tag triggers .github/workflows/build-docker-image.yml, which builds and pushes the image to ghcr.io/code-tool/keepup. The build version is injected via -ldflags "-X main.buildVersion=..." and logged at startup.