donkeyx/tcp-wait repository overview

╭──────────────────────────────────────╮
│   🐴 DonkeyX's tcp-wait              │
╰──────────────────────────────────────╯

        //\\
       (/oo\)   .--------.
       (____)  | WAIT... |
        /||\   '--------'
       //||\\   📡 ping / ready / blip
      ^^ ^^ ^^
   "Is postgres back yet?"

# docker
docker run --rm donkeyx/tcp-wait:latest -version
docker run --rm ghcr.io/donkeyx/tcp-wait:latest -version

# go (note: cmd path — root is the library now)
go install github.com/donkeyx/tcp-wait/v2/cmd/tcp-wait@latest

# or grab a release binary
# https://github.com/donkeyx/tcp-wait/releases

go get github.com/donkeyx/tcp-wait/v2@latest

# basic tcp (-hp is the old flag, still works; -tcp is the same thing)
tcp-wait -hp github.com:443
tcp-wait -tcp db:5432,cache:6379 -t 60

# http readiness
tcp-wait -http http://api:8080/readyz -t 30

# expected status and repeatable request headers
tcp-wait -http https://api:8443/readyz -http-status 204 \
  -http-header 'Authorization: Bearer token' -t 30

# TLS TCP/Redis probes; certificate verification remains enabled by default
tcp-wait -tls -tcp db:5432 -redis cache:6379 -t 60

# actually talk redis / postgres
tcp-wait -redis cache:6379 -postgres db:5432 -t 60

# wait for a file someone else writes
tcp-wait -file /var/run/app.ready -t 30

# wait, then exec your app (handy as a container entrypoint)
tcp-wait -tcp db:5432 -http http://api:8080/readyz \
  -t 60 -dial 2s -interval 500ms \
  -- /app/server --config /config.yaml

# sit on it until Ctrl-C (-t 0 = no time limit)
tcp-wait -watch -postgres db:5432 -redis cache:6379 -t 0 -interval 500ms -o text

# or cap the window (e.g. firewall change)
tcp-wait -w -tcp $HOST:5432 -t 600 -interval 1s -o text

level=INFO msg="check up" check=postgres://db:5432
level=WARN msg="check blip" check=postgres://db:5432 err="..."
level=INFO msg="check up" check=postgres://db:5432
level=INFO msg="watch stopped" status="all up" reason=signal

initContainers:
  - name: wait-deps
    image: donkeyx/tcp-wait:latest
    args: ["-postgres", "db:5432", "-redis", "cache:6379", "-t", "120", "-o", "text"]

command: ["tcp-wait", "-tcp", "db:5432", "-t", "60", "--", "/app/server"]

package main

import (
	"context"
	"errors"
	"log"
	"time"

	tcpwait "github.com/donkeyx/tcp-wait/v2"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	err := tcpwait.Wait(ctx, []tcpwait.Check{
		tcpwait.TCP("db:5432"),
		tcpwait.Redis("cache:6379"),
		tcpwait.Postgres("db:5432"),
		tcpwait.HTTP("http://api:8080/readyz"),
		tcpwait.File("/var/run/app.ready"),
	})
	if err != nil {
		// errors.Is(err, tcpwait.ErrTimeout) — message lists who never came up
		log.Fatal(err)
	}

	// knobs if you need them
	_ = tcpwait.WaitWithOptions(ctx, []tcpwait.Check{tcpwait.TCP("db:5432")}, tcpwait.Options{
		DialTimeout: time.Second,
		Interval:    500 * time.Millisecond,
	})

	// watch until ctx is done (timeout / cancel)
	res, _ := tcpwait.WatchWithOptions(ctx, []tcpwait.Check{
		tcpwait.Postgres("db:5432"),
		tcpwait.Redis("cache:6379"),
	}, tcpwait.Options{Interval: 500 * time.Millisecond})
	if !res.AllUp() {
		log.Printf("still down: %v", res.Down())
	}
}

go test -race ./...
go build -o bin/tcp-wait ./cmd/tcp-wait

make test
make build
make docker-build   # local image tcp-wait:local

goreleaser check
make snapshot   # needs docker + goreleaser

git tag v2.0.1
git push origin v2.0.1