duncanvanzyl/prometheus-announcer

Prometheus Announcer

A gprc server that allows applications to announce themselves to prometheus using prometheus http service discovery.

Announce

Connect using grpc and Announce the service to have it presented using the prometheus http service discovery. The app to be discovered is responsible for reannouncing itself before the announcement lifetime has expired.

Example Announce Function:

import (
	"github.com/google/uuid"
	pa "github.com/duncanvanzyl/prometheus-announcer"
	"github.com/duncanvanzyl/prometheus-announcer/pb"
)
⋮
grpcServer := "localhost:50051"
target := "192.168.1.1:9000"
id := uuid.New().String()
labels := map[string]string{"name": "value"}
⋮
// Note: It is probably worth doing something with the returned error value...
go pa.DialAndAnnounce(ctx, grpcServer, 1*time.Minute, id, target , labels)

Server

There is a functional server in cmd/server. It is intended to be run in docker (or kubernetes). Create the image with make docker-build.

Environment Variable

The following environment variables can be used:

Variable	Function	Default
HSD_GPRCHOST	Port to allow clients to connect to.	:50051
HSD_LOGLEVEL	Logging level.	info
HSD_HTTPHOST	The host and port for prometheus to use for service discovery.	localhost:8080
HSD_LIFETIME	Announcement lifetimes. Announcement expires if not reannounced before this duration.	2m
HSD_INTERVAL	The interval to check for expired announcements.	30s
HSD_WITHREST	Enable the REST API.	true

REST API

A endpoint for adding targets over http is available at "http://<HSD_HTTPHOST>/v1/announce".
The REST api is enabled by default, but can be disabled by setting HST_WITHREST=false.

Announcements can be made by sending an appropriate POST request to the server.

curl -d '{"id":"asdf","targets":["10.13.200.249:2113"],"labels":{"name1":"value1"}}' -H "Content-Type: application/json" -X POST http://localhost:8080/v1/announce

Client

There is a functional client in cmd/client. It is intended to be run from the command line, or via systemd. Create the executable with make client.

Flags

The following flags can be used:

• -id
  • Unique ID for this announcer.
    If not provided a random uuid will be used.
  • [type] string
• -labels
  • Labels to tag metrics scraped from the supplied targets with.
    Must be in the form: "name1:value1,name2:value2".
    Label names may contain ASCII letters, numbers, as well as underscores and must
    match the regex "[a-zA-Z_][a-zA-Z0-9_]*".
    Label values may contain any Unicode characters.
  • [type] string

Environment Variables

The following environment variables can be used:

• HTTPSD_INTERVAL
  • The interval between announcements.
  • [type] Duration
  • [default] 1m
• HTTPSD_GRPCSERVER
  • The GRPC server to announce to.
    In the form "host:port"
  • [type] String
  • [default] localhost:50051