third_party/wait-for-it: replace with a simple go program

The program doesn't have all the features of wait-for-it, but it
implements the core functionality we need.

For golang/go#61399

Change-Id: Ia5498523e44b74dcd5af1c984521f1a46208d2c5
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/552295
kokoro-CI: kokoro <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Jonathan Amsterdam <[email protected]>

devtools/cmd/wait_available/main.go

@@ -0,0 +1,66 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix
+
+package main
+
+import (
+	"context"
+	"net"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"golang.org/x/pkgsite/internal/log"
+)
+
+var timeout = 15 * time.Second
+
+func main() {
+	ctx := context.Background()
+
+	if len(os.Args) < 2 {
+		log.Fatalf(ctx, "expected at least one argument; got none")
+	}
+	hostport := os.Args[1]
+	var command []string
+
+	if len(os.Args) > 2 {
+		if os.Args[2] != "--" {
+			log.Fatalf(ctx, "expected second argument to be \"--\"; got %q", os.Args[2])
+		}
+		command = os.Args[3:]
+	}
+
+	start := time.Now()
+	for {
+		if time.Since(start) > timeout {
+			break
+		}
+		if conn, err := net.DialTimeout("tcp", hostport, 1*time.Second); err != nil {
+			time.Sleep(1 * time.Second)
+			continue
+		} else {
+			conn.Close()
+			break
+		}
+	}
+	var err error
+	binpath := command[0]
+	if !filepath.IsAbs(binpath) {
+		binpath, err = exec.LookPath(command[0])
+		if err != nil {
+			log.Fatalf(ctx, "looking up err: %v", err)
+		}
+	}
+	if len(command) > 0 {
+		err := syscall.Exec(binpath, command, os.Environ())
+		if err != nil {
+			log.Fatalf(ctx, "exec-ing binary: %v", err)
+		}
+	}
+}

devtools/docker/compose.yaml

@@ -38,7 +38,7 @@ services:
       # TERM is set to xterm-256color for use by devtools/lib.sh.
       TERM: xterm-256color
       WAITFORIT_TIMEOUT: 300
-    entrypoint: ./third_party/wait-for-it/wait-for-it.sh db:5432 -- ./all.bash
+    entrypoint: go run ./devtools/cmd/wait_available db:5432 -- ./all.bash
     volumes:
       - ../../:/pkgsite
     working_dir: /pkgsite
@@ -49,7 +49,7 @@ services:
     environment:
       <<: [*database-variables, *go-variables]
       WAITFORIT_TIMEOUT: 300
-    entrypoint: ./third_party/wait-for-it/wait-for-it.sh frontend:8080 -- go run
+    entrypoint: go run ./devtools/cmd/wait_available frontend:8080 -- go run
     command: "tests/search/main.go -frontend http://frontend:8080"
     volumes:
       - ../../:/pkgsite
@@ -61,7 +61,7 @@ services:
     environment:
       <<: *go-variables
       WAITFORIT_TIMEOUT: 300
-    entrypoint: ./third_party/wait-for-it/wait-for-it.sh frontend:8080 -- go run
+    entrypoint: go run ./devtools/cmd/wait_available frontend:8080 -- go run
     command: "tests/api/main.go -frontend http://frontend:8080 -all compare "
     volumes:
       - ../../:/pkgsite
@@ -72,7 +72,7 @@ services:
     depends_on:
       - db
     command: bash -c "
-        ./third_party/wait-for-it/wait-for-it.sh db:5432 --
+        go run ./devtools/cmd/wait_available db:5432 --
           go run ./devtools/cmd/db/main.go create &&
           go run ./devtools/cmd/db/main.go migrate &&
           go run ./cmd/frontend -host=0.0.0.0:8080"
@@ -94,7 +94,7 @@ services:
     # time seeddb runs. If this ends up being flaky, we should add a check here.
     command: bash -c "
         echo GO_DISCOVERY_CONFIG_DYNAMIC=$GO_DISCOVERY_CONFIG_DYNAMIC &&
-        ./third_party/wait-for-it/wait-for-it.sh db:5432 --
+        go run ./devtools/cmd/wait_available db:5432 --
           go run ./devtools/cmd/db/main.go create &&
           go run ./devtools/cmd/db/main.go migrate &&
           go run ./devtools/cmd/seeddb/main.go -seed ${GO_DISCOVERY_SEED_DB_FILE:-seed.txt}"

tests/screentest/run.sh

@@ -133,7 +133,7 @@ main() {
     dcompose run --rm --entrypoint bash go -c "
       export WAITFORIT_TIMEOUT=120
       go install golang.org/x/website/cmd/screentest@latest
-      ./third_party/wait-for-it/wait-for-it.sh frontend:8080 --
+      go run ./devtools/cmd/wait_available frontend:8080 --
       $(echo $cmd)"
   elif [ "$env" = local ]; then
     if ! nc -z localhost 9222; then