Add support for setcap from build command (#129)

.goreleaser.yml

@@ -34,9 +34,9 @@ builds:
   - s390x
   - ppc64le
   goarm:
-  - 5
-  - 6
-  - 7
+  - "5"
+  - "6"
+  - "7"
   ignore:
     - goos: darwin
       goarch: arm
@@ -54,7 +54,7 @@ builds:
       goarch: s390x
     - goos: freebsd
       goarch: arm
-      goarm: 5
+      goarm: "5"
   flags:
   - -trimpath
   ldflags:
@@ -64,8 +64,15 @@ archives:
   - format_overrides:
       - goos: windows
         format: zip
-    replacements:
-      darwin: mac
+    name_template: >-
+      {{ .ProjectName }}_
+      {{- .Version }}_
+      {{- if eq .Os "darwin" }}mac{{ else }}{{ .Os }}{{ end }}_
+      {{- .Arch }}
+      {{- with .Arm }}v{{ . }}{{ end }}
+      {{- with .Mips }}_{{ . }}{{ end }}
+      {{- if not (eq .Amd64 "v1") }}{{ .Amd64 }}{{ end }}
+
 checksum:
   algorithm: sha512
 

README.md

@@ -167,7 +167,7 @@ Because the subcommands and flags are constrained to benefit rapid plugin protot
 - `CADDY_VERSION` sets the version of Caddy to build.
 - `XCADDY_RACE_DETECTOR=1` enables the Go race detector in the build.
 - `XCADDY_DEBUG=1` enables the DWARF debug information in the build.
-- `XCADDY_SETCAP=1` will run `sudo setcap cap_net_bind_service=+ep` on the temporary binary before running it when in dev mode.
+- `XCADDY_SETCAP=1` will run `sudo setcap cap_net_bind_service=+ep` on the resulting binary. By default, the `sudo` command will be used if it is found; set `XCADDY_SUDO=0` to avoid using `sudo` if necessary.
 - `XCADDY_SKIP_BUILD=1` causes xcaddy to not compile the program, it is used in conjunction with build tools such as [GoReleaser](https://goreleaser.com). Implies `XCADDY_SKIP_CLEANUP=1`.
 - `XCADDY_SKIP_CLEANUP=1` causes xcaddy to leave build artifacts on disk after exiting.
 - `XCADDY_WHICH_GO` sets the go command to use when for example more then 1 version of go is installed.

cmd/main.go

@@ -144,6 +144,12 @@ func runBuild(ctx context.Context, args []string) error {
 		log.Fatalf("[FATAL] %v", err)
 	}
 
+	// if requested, run setcap to allow binding to low ports
+	err = setcapIfRequested(output)
+	if err != nil {
+		return err
+	}
+
 	// prove the build is working by printing the version
 	if runtime.GOOS == os.Getenv("GOOS") && runtime.GOARCH == os.Getenv("GOARCH") {
 		if !filepath.IsAbs(output) {
@@ -223,14 +229,10 @@ func runDev(ctx context.Context, args []string) error {
 		return err
 	}
 
-	if os.Getenv("XCADDY_SETCAP") == "1" {
-		cmd = exec.Command("sudo", "setcap", "cap_net_bind_service=+ep", binOutput)
-		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
-		log.Printf("[INFO] Setting capabilities (requires admin privileges): %v", cmd.Args)
-		if err = cmd.Run(); err != nil {
-			return err
-		}
+	// if requested, run setcap to allow binding to low ports
+	err = setcapIfRequested(binOutput)
+	if err != nil {
+		return err
 	}
 
 	log.Printf("[INFO] Running %v\n\n", append([]string{binOutput}, args...))
@@ -257,6 +259,34 @@ func runDev(ctx context.Context, args []string) error {
 	return cmd.Wait()
 }
 
+func setcapIfRequested(output string) error {
+	if os.Getenv("XCADDY_SETCAP") != "1" {
+		return nil
+	}
+
+	args := []string{"setcap", "cap_net_bind_service=+ep", output}
+
+	// check if sudo isn't available, or we were instructed not to use it
+	_, sudoNotFound := exec.LookPath("sudo")
+	skipSudo := sudoNotFound != nil || os.Getenv("XCADDY_SUDO") == "0"
+
+	var cmd *exec.Cmd
+	if skipSudo {
+		cmd = exec.Command(args[0], args[1:]...)
+	} else {
+		cmd = exec.Command("sudo", args...)
+	}
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	log.Printf("[INFO] Setting capabilities (requires admin privileges): %v", cmd.Args)
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("failed to setcap on the binary: %v", err)
+	}
+
+	return nil
+}
+
 type module struct {
 	Path    string  // module path
 	Version string  // module version