AppDir/AppRun

@@ -1,4 +1,4 @@
 #!/bin/sh
 
 export PATH=$APPDIR/bin
-exec entrypoint "$@"
+exec cryptic-net-main entrypoint "$@"

AppDir/bin/wait-for-ip

@@ -0,0 +1,9 @@
+
+ip="$1"
+shift;
+
+echo "waiting for $ip to become available..."
+
+while true; do ping -c1 -W1 "$ip" &> /dev/null && break; done
+
+exec "$@"

default.nix

@@ -1,13 +1,9 @@
 {
 
-  pkgsAttrs ? (import ./nix/pkgs.nix),
+  pkgs ? (import ./nix/pkgs.nix).stable,
   bootstrap ? null,
 
-}: let
+}: rec {
-
-  pkgs = pkgsAttrs.pkgs;
-
-in rec {
 
   rootedBootstrap = pkgs.stdenv.mkDerivation {
     name = "cryptic-net-rooted-bootstrap";
@@ -25,37 +21,30 @@ in rec {
     name = "cryptic-net-version";
 
     buildInputs = [ pkgs.git pkgs.go ];
-
     src = ./.;
     inherit bootstrap;
-    nixPkgsVersion = pkgsAttrs.version;
-    nixPkgsRev = pkgsAttrs.rev;
-    builtByUser = builtins.getEnv "USER";
 
     builder = builtins.toFile "builder.sh" ''
       source $stdenv/setup
 
       versionFile=version
 
-      cp -r "$src" srcCp
-
       if [ "$bootstrap" != "" ]; then
         hostName=$(tar -xzf "$bootstrap" --to-stdout ./hostname)
         echo "Built for host:  $hostName" >> "$versionFile"
       fi
 
-      echo "Build date:      $(date) ($(date +%s))" >> "$versionFile"
+      echo "Build date:      $(date)" >> "$versionFile"
-      echo "Built by:        $builtByUser" >> "$versionFile"
+      echo "Git status:      $(cd "$src" && git describe --always --long --dirty=' (dirty)')" >> "$versionFile"
-      echo "Git rev:         $(cd srcCp && git describe --always --long --dirty=' (dirty)')" >> "$versionFile"
       echo "Go version:      $(go version)" >> "$versionFile"
-      echo "Nixpkgs version: $nixPkgsVersion ($nixPkgsRev)" >> "$versionFile"
+      echo "Build host info: $(uname -srvm)" >> "$versionFile"
 
       mkdir -p "$out"/share
       cp "$versionFile" "$out"/share
     '';
   };
 
-  entrypoint = pkgs.callPackage ./entrypoint {};
+  goWorkspace = pkgs.callPackage ./go-workspace {};
 
   dnsmasq = (pkgs.callPackage ./dnsmasq {
     glibcStatic = pkgs.glibc.static;
@@ -71,6 +60,8 @@ in rec {
 
       pkgs.pkgsStatic.bash
       pkgs.pkgsStatic.coreutils
+      pkgs.pkgsStatic.unixtools.ping
+      pkgs.pkgsStatic.netcat # required by waitFor
       pkgs.pkgsStatic.gnutar
       pkgs.pkgsStatic.gzip
 
@@ -82,7 +73,8 @@ in rec {
       version
       dnsmasq
       garage
-      entrypoint
+      waitFor
+      goWorkspace.crypticNetMain
 
     ] ++ (if bootstrap != null then [ rootedBootstrap ] else []);
   };

docs/shell.nix

@@ -1,6 +1,6 @@
 {
 
-  pkgs ? (import ../nix/pkgs.nix).pkgs,
+  pkgs ? (import ../nix/pkgs.nix).stable,
 
 }: pkgs.mkShell {
   name = "cryptic-net-build-docs";

entrypoint/default.nix

@@ -1,14 +0,0 @@
-{
-
-  buildGoModule,
-
-}: buildGoModule {
-
-  pname = "cryptic-net-entrypoint";
-  version = "unstable";
-  src = ./src;
-  vendorSha256 = "sha256-URmrK9Sd/5yhXrWxXZq05TS7aY7IWptQFMKfXKJY7Hc=";
-  subPackages = [
-    "cmd/entrypoint"
-  ];
-}

go-workspace/README.md

@@ -0,0 +1,9 @@
+# go-workspace
+
+This module is used for building all custom go binaries within the cryptic-net
+project.
+
+The reason binaries are contained here, and not under the sub-directory for the
+sub-process the correspond to like most other code in this project, is that nix
+makes it difficult to compose multiple modules defined locally. If nix ever
+fixes this we should split this out.

go-workspace/default.nix

@@ -0,0 +1,18 @@
+{
+  buildGoModule,
+}: let
+
+  build = subPackage: buildGoModule {
+
+    pname = "cryptic-net-" + (builtins.baseNameOf subPackage);
+    version = "unstable";
+    src = ./src;
+    vendorSha256 = "sha256-URmrK9Sd/5yhXrWxXZq05TS7aY7IWptQFMKfXKJY7Hc=";
+    subPackages = [
+      subPackage
+    ];
+  };
+
+in {
+  crypticNetMain = build "cmd/cryptic-net-main";
+}

go-workspace/src/cmd/cryptic-net-main/main.go

@@ -0,0 +1,73 @@
+package main
+
+//
+// This binary acts as a wrapper around other programs which would otherwise
+// form their own binaries. We do this for two reasons:
+//
+// * Nix makes it difficult to determine which individuals binaries need to be
+// rebuilt upon changes, so it rebuilds all of them no matter what changed. This
+// makes development slow. By wrapping everything in a sinble binary we only
+// ever have to build that binary.
+//
+// * If we have N binaries total, then we have N copies of the go runtime in our
+// final AppImage. By bundling the binaries into a single one we can reduce the
+// number go runtime copies to 1.
+//
+
+import (
+	"cryptic-net/cmd/entrypoint"
+	nebula_entrypoint "cryptic-net/cmd/nebula-entrypoint"
+	"fmt"
+	"os"
+)
+
+type mainFn struct {
+	name string
+	fn   func()
+}
+
+var mainFns = []mainFn{
+	{"entrypoint", entrypoint.Main},
+	{"nebula-entrypoint", nebula_entrypoint.Main},
+}
+
+var mainFnsMap = func() map[string]mainFn {
+
+	m := map[string]mainFn{}
+
+	for _, mainFn := range mainFns {
+		m[mainFn.name] = mainFn
+	}
+
+	return m
+}()
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "USAGE: %s <cmd>\n\n", os.Args[0])
+	fmt.Fprintf(os.Stderr, "Commands:\n\n")
+
+	for _, mainFn := range mainFns {
+		fmt.Fprintf(os.Stderr, "%s\n", mainFn.name)
+	}
+
+	os.Stderr.Sync()
+	os.Exit(1)
+}
+
+func main() {
+
+	if len(os.Args) < 2 {
+		usage()
+	}
+
+	mainFn, ok := mainFnsMap[os.Args[1]]
+	if !ok {
+		usage()
+	}
+
+	// remove os.Args[1] from the arg list, so that other commands which consume
+	// args don't get confused
+	os.Args = append(os.Args[:1], os.Args[2:]...)
+
+	mainFn.fn()
+}

go-workspace/src/cmd/entrypoint/admin.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"context"
@@ -173,22 +173,17 @@ var subCmdAdminCreateNetwork = subCmd{
 			}
 		}
 
-		nebulaPmuxProcConfig, err := nebulaPmuxProcConfig(env)
+		garageChildrenPmuxProcConfigs, err := garageChildrenPmuxProcConfigs(env)
 		if err != nil {
-			return fmt.Errorf("generating nebula config: %w", err)
+			return fmt.Errorf("generating garage children configs: %w", err)
-		}
-
-		garagePmuxProcConfigs, err := garagePmuxProcConfigs(env)
-		if err != nil {
-			return fmt.Errorf("generating garage configs: %w", err)
 		}
 
 		pmuxConfig := pmuxlib.Config{
 			Processes: append(
 				[]pmuxlib.ProcessConfig{
-					nebulaPmuxProcConfig,
+					nebulaEntrypointPmuxProcConfig(),
 				},
-				garagePmuxProcConfigs...,
+				garageChildrenPmuxProcConfigs...,
 			),
 		}
 
@@ -208,7 +203,7 @@ var subCmdAdminCreateNetwork = subCmd{
 		}()
 
 		fmt.Fprintln(os.Stderr, "waiting for garage instances to come online")
-		if err := waitForGarageAndNebula(ctx, env); err != nil {
+		if err := waitForGarage(ctx, env); err != nil {
 			return fmt.Errorf("waiting for garage to start up: %w", err)
 		}
 

go-workspace/src/cmd/entrypoint/daemon.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"bytes"
@@ -74,46 +74,33 @@ func reloadBootstrap(env crypticnet.Env, s3Client garage.S3APIClient) (crypticne
 	return env, true, nil
 }
 
-// runs a single pmux process of daemon, returning only once the env.Context has
+// runs a single pmux process ofor daemon, returning only once the env.Context
-// been canceled or bootstrap info has been changed. This will always block
+// has been canceled or bootstrap info has been changed. This will always block
 // until the spawned pmux has returned, and returns a copy of Env with updated
 // boostrap info.
-func runDaemonPmuxOnce(env crypticnet.Env) (crypticnet.Env, error) {
+func runDaemonPmuxOnce(env crypticnet.Env, s3Client garage.S3APIClient) (crypticnet.Env, error) {
 
 	thisHost := env.Bootstrap.ThisHost()
 	thisDaemon := env.ThisDaemon()
 	fmt.Fprintf(os.Stderr, "host name is %q, ip is %q\n", thisHost.Name, thisHost.Nebula.IP)
 
-	// create s3Client anew on every loop, in case the topology has
-	// changed and we should be connecting to a different garage
-	// endpoint.
-	s3Client := env.Bootstrap.GlobalBucketS3APIClient()
-
-	nebulaPmuxProcConfig, err := nebulaPmuxProcConfig(env)
-	if err != nil {
-		return crypticnet.Env{}, fmt.Errorf("generating nebula config: %w", err)
-	}
-
 	pmuxProcConfigs := []pmuxlib.ProcessConfig{
-		nebulaPmuxProcConfig,
+		nebulaEntrypointPmuxProcConfig(),
 		{
 			Name: "dnsmasq",
 			Cmd:  "bash",
-			Args: []string{"dnsmasq-entrypoint"},
+			Args: waitForNebulaArgs(env, "dnsmasq-entrypoint"),
-			StartAfterFunc: func(ctx context.Context) error {
-				return waitForNebula(ctx, env)
-			},
 		},
 	}
 
 	if len(thisDaemon.Storage.Allocations) > 0 {
 
-		garagePmuxProcConfigs, err := garagePmuxProcConfigs(env)
+		garageChildrenPmuxProcConfigs, err := garageChildrenPmuxProcConfigs(env)
 		if err != nil {
 			return crypticnet.Env{}, fmt.Errorf("generating garage children configs: %w", err)
 		}
 
-		pmuxProcConfigs = append(pmuxProcConfigs, garagePmuxProcConfigs...)
+		pmuxProcConfigs = append(pmuxProcConfigs, garageChildrenPmuxProcConfigs...)
 	}
 
 	pmuxConfig := pmuxlib.Config{Processes: pmuxProcConfigs}
@@ -136,16 +123,14 @@ func runDaemonPmuxOnce(env crypticnet.Env) (crypticnet.Env, error) {
 	go func() {
 		defer wg.Done()
 
-		if err := waitForGarageAndNebula(ctx, env); err != nil {
+		// TODO wait for garage or nebula, depending on if allocs are present
-			fmt.Fprintf(os.Stderr, "aborted waiting for garage instances to be accessible: %v\n", err)
-			return
-		}
 
+		client := env.Bootstrap.GlobalBucketS3APIClient()
 		thisHost := env.Bootstrap.ThisHost()
 
 		err := doOnce(ctx, func(ctx context.Context) error {
 			fmt.Fprintln(os.Stderr, "updating host info in garage")
-			return bootstrap.PutGarageBoostrapHost(ctx, s3Client, thisHost)
+			return bootstrap.PutGarageBoostrapHost(ctx, client, thisHost)
 		})
 
 		if err != nil {
@@ -158,8 +143,8 @@ func runDaemonPmuxOnce(env crypticnet.Env) (crypticnet.Env, error) {
 		go func() {
 			defer wg.Done()
 
-			if err := waitForGarageAndNebula(ctx, env); err != nil {
+			if err := waitForGarage(ctx, env); err != nil {
-				fmt.Fprintf(os.Stderr, "aborted waiting for garage instances to be accessible: %v\n", err)
+				fmt.Fprintf(os.Stderr, "aborted waiting for garage instances to start: %v\n", err)
 				return
 			}
 
@@ -302,9 +287,6 @@ var subCmdDaemon = subCmd{
 			return fmt.Errorf("merging daemon.yml into bootstrap data: %w", err)
 		}
 
-		// TODO once dnsmasq entrypoint is written in go and the config
-		// generation is inlined into this process then this Setenv won't be
-		// necessary.
 		for key, val := range env.ToMap() {
 			if err := os.Setenv(key, val); err != nil {
 				return fmt.Errorf("failed to set %q to %q: %w", key, val, err)
@@ -313,7 +295,12 @@ var subCmdDaemon = subCmd{
 
 		for {
 
-			if env, err = runDaemonPmuxOnce(env); errors.Is(err, context.Canceled) {
+			// create s3Client anew on every loop, in case the topology has
+			// changed and we should be connecting to a different garage
+			// endpoint.
+			s3Client := env.Bootstrap.GlobalBucketS3APIClient()
+
+			if env, err = runDaemonPmuxOnce(env, s3Client); errors.Is(err, context.Canceled) {
 				return nil
 
 			} else if err != nil {

go-workspace/src/cmd/entrypoint/daemon_util.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"bytes"
@@ -9,7 +9,8 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"time"
+
+	"code.betamike.com/cryptic-io/pmux/pmuxlib"
 )
 
 func copyBootstrapToDataDirAndReload(env crypticnet.Env, r io.Reader) (crypticnet.Env, error) {
@@ -73,7 +74,20 @@ func doOnce(ctx context.Context, fn func(context.Context) error) error {
 		} else if ctxErr := ctx.Err(); ctxErr != nil {
 			return ctxErr
 		}
+	}
+}
 
-		time.Sleep(250 * time.Millisecond)
+func waitForNebulaArgs(env crypticnet.Env, args ...string) []string {
+	thisHost := env.Bootstrap.ThisHost()
+	return append([]string{"wait-for-ip", thisHost.Nebula.IP}, args...)
+}
+
+func nebulaEntrypointPmuxProcConfig() pmuxlib.ProcessConfig {
+	return pmuxlib.ProcessConfig{
+		Name: "nebula",
+		Cmd:  "cryptic-net-main",
+		Args: []string{
+			"nebula-entrypoint",
+		},
 	}
 }

go-workspace/src/cmd/entrypoint/daemon_yml.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	crypticnet "cryptic-net"

go-workspace/src/cmd/entrypoint/garage.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"fmt"

go-workspace/src/cmd/entrypoint/garage_util.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"context"
@@ -9,21 +9,14 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
+	"time"
 
 	"code.betamike.com/cryptic-io/pmux/pmuxlib"
 )
 
-func waitForGarageAndNebula(ctx context.Context, env crypticnet.Env) error {
+func waitForGarage(ctx context.Context, env crypticnet.Env) error {
 
-	allocs := env.ThisDaemon().Storage.Allocations
+	for _, alloc := range env.ThisDaemon().Storage.Allocations {
-
-	// if this host doesn't have any allocations specified then fall back to
-	// waiting for nebula
-	if len(allocs) == 0 {
-		return waitForNebula(ctx, env)
-	}
-
-	for _, alloc := range allocs {
 
 		adminAddr := net.JoinHostPort(
 			env.Bootstrap.ThisHost().Nebula.IP,
@@ -44,6 +37,29 @@ func waitForGarageAndNebula(ctx context.Context, env crypticnet.Env) error {
 
 }
 
+func waitForGarageArgs(env crypticnet.Env, args ...string) []string {
+
+	thisHost := env.Bootstrap.ThisHost()
+	allocs := env.ThisDaemon().Storage.Allocations
+
+	if len(allocs) == 0 {
+		return waitForNebulaArgs(env, args...)
+	}
+
+	var preArgs []string
+
+	for _, alloc := range allocs {
+		preArgs = append(
+			preArgs,
+			"wait-for",
+			net.JoinHostPort(thisHost.Nebula.IP, strconv.Itoa(alloc.RPCPort)),
+			"--",
+		)
+	}
+
+	return append(preArgs, args...)
+}
+
 func garageWriteChildConf(
 	env crypticnet.Env,
 	alloc crypticnet.DaemonYmlStorageAllocation,
@@ -100,7 +116,7 @@ func garageWriteChildConf(
 	return garageTomlPath, nil
 }
 
-func garagePmuxProcConfigs(env crypticnet.Env) ([]pmuxlib.ProcessConfig, error) {
+func garageChildrenPmuxProcConfigs(env crypticnet.Env) ([]pmuxlib.ProcessConfig, error) {
 
 	var pmuxProcConfigs []pmuxlib.ProcessConfig
 
@@ -116,15 +132,22 @@ func garagePmuxProcConfigs(env crypticnet.Env) ([]pmuxlib.ProcessConfig, error)
 			Name:        fmt.Sprintf("garage-%d", alloc.RPCPort),
 			Cmd:         "garage",
 			Args:        []string{"-c", childConfPath, "server"},
-			StartAfterFunc: func(ctx context.Context) error {
+			SigKillWait: 1 * time.Minute,
-				return waitForNebula(ctx, env)
-			},
 		})
 	}
 
 	return pmuxProcConfigs, nil
 }
 
+func garageApplyLayoutDiffPmuxProcConfig(env crypticnet.Env) pmuxlib.ProcessConfig {
+	return pmuxlib.ProcessConfig{
+		Name:        "garage-apply-layout-diff",
+		Cmd:         "bash",
+		Args:        waitForGarageArgs(env, "bash", "garage-apply-layout-diff"),
+		NoRestartOn: []int{0},
+	}
+}
+
 func garageInitializeGlobalBucket(ctx context.Context, env crypticnet.Env) error {
 
 	var (

go-workspace/src/cmd/entrypoint/hosts.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"cryptic-net/bootstrap"

go-workspace/src/cmd/entrypoint/main.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"fmt"
@@ -12,7 +12,7 @@ import (
 // then passes execution along to an appropriate binary housed in AppDir/bin
 // (usually a bash script, which is more versatile than a go program).
 
-func main() {
+func Main() {
 
 	env, err := crypticnet.NewEnv(true)
 

go-workspace/src/cmd/entrypoint/sub_cmd.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	crypticnet "cryptic-net"

go-workspace/src/cmd/entrypoint/version.go

@@ -1,4 +1,4 @@
-package main
+package entrypoint
 
 import (
 	"fmt"

go-workspace/src/cmd/nebula-entrypoint/main.go

@@ -1,40 +1,24 @@
-package main
+package nebula_entrypoint
 
 import (
-	"context"
-	crypticnet "cryptic-net"
 	"cryptic-net/yamlutil"
-	"fmt"
+	"log"
 	"net"
+	"os"
 	"path/filepath"
 	"strconv"
+	"syscall"
 
-	"code.betamike.com/cryptic-io/pmux/pmuxlib"
+	crypticnet "cryptic-net"
 )
 
-// waitForNebula waits for the nebula interface to have been started up. It does
+func Main() {
-// this by attempting to create a UDP connection which has the nebula IP set as
-// its source. If this succeeds we can assume that at the very least the nebula
-// interface has been initialized.
-func waitForNebula(ctx context.Context, env crypticnet.Env) error {
 
-	ipStr := env.Bootstrap.ThisHost().Nebula.IP
+	env, err := crypticnet.ReadEnv()
-	ip := net.ParseIP(ipStr)
 
-	lUdpAddr := &net.UDPAddr{IP: ip, Port: 0}
-	rUdpAddr := &net.UDPAddr{IP: ip, Port: 45535}
-
-	return doOnce(ctx, func(context.Context) error {
-		conn, err := net.DialUDP("udp", lUdpAddr, rUdpAddr)
 	if err != nil {
-			return err
+		log.Fatalf("reading envvars: %v", err)
 	}
-		conn.Close()
-		return nil
-	})
-}
-
-func nebulaPmuxProcConfig(env crypticnet.Env) (pmuxlib.ProcessConfig, error) {
 
 	var (
 		lighthouseHostIPs []string
@@ -67,6 +51,10 @@ func nebulaPmuxProcConfig(env crypticnet.Env) (pmuxlib.ProcessConfig, error) {
 		},
 	}
 
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	if publicAddr := env.ThisDaemon().VPN.PublicAddr; publicAddr == "" {
 
 		config["listen"] = map[string]string{
@@ -83,7 +71,7 @@ func nebulaPmuxProcConfig(env crypticnet.Env) (pmuxlib.ProcessConfig, error) {
 		_, port, err := net.SplitHostPort(publicAddr)
 
 		if err != nil {
-			return pmuxlib.ProcessConfig{}, fmt.Errorf("parsing public address %q: %w", publicAddr, err)
+			log.Fatalf("parsing public address %q: %v", publicAddr, err)
 		}
 
 		config["listen"] = map[string]string{
@@ -126,12 +114,16 @@ func nebulaPmuxProcConfig(env crypticnet.Env) (pmuxlib.ProcessConfig, error) {
 	nebulaYmlPath := filepath.Join(env.RuntimeDirPath, "nebula.yml")
 
 	if err := yamlutil.WriteYamlFile(config, nebulaYmlPath); err != nil {
-		return pmuxlib.ProcessConfig{}, fmt.Errorf("writing nebula.yml to %q: %w", nebulaYmlPath, err)
+		log.Fatalf("writing nebula.yml to %q: %v", nebulaYmlPath, err)
 	}
 
-	return pmuxlib.ProcessConfig{
+	var (
-		Name: "nebula",
+		binPath = env.BinPath("nebula")
-		Cmd:  "nebula",
+		args    = []string{"nebula", "-config", nebulaYmlPath}
-		Args: []string{"-config", nebulaYmlPath},
+		cliEnv  = os.Environ()
-	}, nil
+	)
+
+	if err := syscall.Exec(binPath, args, cliEnv); err != nil {
+		log.Fatalf("calling exec(%q, %#v, %#v)", binPath, args, cliEnv)
+	}
 }

nix/pkgs.nix

@@ -16,7 +16,6 @@ rec {
 
       in {
 
-        go = prev.go_1_18;
         buildGoModule = args: prev.buildGoModule (buildArgs // args);
         buildGo118Module = args: prev.buildGo118Module (buildArgs // args);
 
@@ -32,14 +31,11 @@ rec {
 
   ];
 
-  version = "22-05";
+  stableSrc = fetchTarball {
-  rev = "2aec372cdcd4d73b94863611fea70e0884270fdc";
+    name = "nixpkgs-22-05";
-
+    url = "https://github.com/NixOS/nixpkgs/archive/2aec372cdcd4d73b94863611fea70e0884270fdc.tar.gz";
-  src = fetchTarball {
-    name = "nixpkgs-${version}";
-    url = "https://github.com/NixOS/nixpkgs/archive/${rev}.tar.gz";
     sha256 = "1pbfhlh4v8l70p44gspsci3i6w0wk70vaisiawg3jhka2nxb8367";
   };
 
-  pkgs = import src { inherit overlays; };
+  stable = import stableSrc { inherit overlays; };
 }

nix/wait-for.nix

@@ -0,0 +1,21 @@
+{
+  fetchFromGitHub,
+  stdenv,
+}: stdenv.mkDerivation rec {
+
+  pname = "cryptic-net-wait-for";
+  version = "2.2.2";
+
+  src = fetchFromGitHub {
+    owner = "eficode";
+    repo = "wait-for";
+    rev = "v${version}";
+    sha256 = "sha256-qYeBOF63/+8bbFHiR6HT2mMQDFKCVkLNzIGLeEZJ4sk=";
+  };
+
+  builder = builtins.toFile "builder.sh" ''
+    source $stdenv/setup
+    mkdir -p "$out"/bin
+    cp "$src"/wait-for "$out"/bin/
+  '';
+}