Find and listen on all available networks

.github/workflows/ci.yml

@@ -10,9 +10,9 @@ on:
 jobs:
   format:
     strategy:
-      matrix: 
+      matrix:
         os: [ 'ubuntu-latest' ]
-        go: [ '1.17' ]
+        go: [ '1.19' ]
 
     runs-on: ${{ matrix.os }}
 
@@ -34,9 +34,9 @@ jobs:
 
   test:
     strategy:
-      matrix: 
+      matrix:
         os: [ 'macos-latest', 'ubuntu-latest', 'windows-latest' ]
-        go: [ '1.17' ]
+        go: [ '1.18', '1.19' ]
 
     runs-on: ${{ matrix.os }}
 
@@ -68,7 +68,7 @@ jobs:
           - os: 'windows-latest'
             goos: 'windows'
             goarch: 'amd64'
-        go: [ '1.17' ]
+        go: [ '1.18', '1.19' ]
 
     runs-on: ${{ matrix.target.os }}
 

Makefile

@@ -0,0 +1,27 @@
+.PHONY: all
+all: build lint
+
+.PHONY: build
+build:
+	go build
+
+# Build all compiling os-arch combinations just to check for regressions. Output
+# binaries get deleted.
+.PHONY: all-osarchs
+all-osarchs:
+	TMPDIR=$${TMPDIR:-/tmp}
+	GOOSNOT="android|ios|js|plan9"; \
+	for dist in $$(go tool dist list | egrep -v "^($$GOOSNOT)/|^darwin/amd64$$"); do \
+		echo "  GOOS=$${dist%/*} GOARCH=$${dist#*/}"; \
+		GOOS=$${dist%/*} GOARCH=$${dist#*/} go build -o $$TMPDIR/alpaca && \
+			printf '\e[A\e[1;32m✔\e[0m\n'; \
+	done; \
+	rm $$TMPDIR/alpaca
+
+.PHONY: test
+test:
+	go test ./...
+
+.PHONY: lint
+lint:
+	golangci-lint run

go.mod

@@ -1,6 +1,6 @@
 module github.com/samuong/alpaca
 
-go 1.17
+go 1.19
 
 require (
 	github.com/Azure/go-ntlmssp v0.0.0-20211209120228-48547f28849e

gogroup.go

@@ -0,0 +1,18 @@
+package main
+
+// Run a group of goroutines and report the first error.
+func gogroup[T any](args []T, f func(T) error) error {
+	errch := make(chan error)
+
+	gopher := func(arg T) {
+		if err := f(arg); err != nil {
+			errch <- err
+		}
+	}
+
+	for _, arg := range args {
+		go gopher(arg)
+	}
+
+	return <-errch
+}

main.go

@@ -80,10 +80,14 @@ func main() {
 	}
 
 	s := createServer(*host, *port, *pacurl, a)
-	log.Printf("Listening on %s", s.Addr)
-	if err := s.ListenAndServe(); err != nil {
-		log.Fatal(err)
-	}
+	log.Fatal(gogroup(networks(*host), func(network string) error {
+		listener, err := net.Listen(network, s.Addr)
+		if err != nil {
+			return err
+		}
+		log.Printf("Listening on %s %s", network, s.Addr)
+		return s.Serve(listener)
+	}))
 }
 
 func createServer(host string, port int, pacurl string, a *authenticator) *http.Server {

net.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"log"
+	"net"
+)
+
+func networks(hostname string) []string {
+	if hostname == "" {
+		return []string{"tcp"}
+	}
+	addrs, err := net.LookupIP(hostname)
+	if err != nil {
+		log.Fatal(err)
+	}
+	nets := make([]string, 0, 2)
+	ipv4 := false
+	ipv6 := false
+	for _, addr := range addrs {
+		// addr == net.IPv4len doesn't work because all addrs use IPv6 format.
+		if addr.To4() != nil {
+			ipv4 = true
+		} else {
+			ipv6 = true
+		}
+	}
+	if ipv4 {
+		nets = append(nets, "tcp4")
+	}
+	if ipv6 {
+		nets = append(nets, "tcp6")
+	}
+	return nets
+}