Ability to change the HTTP network protocol

cmd/packer-sdc/internal/renderdocs/docs-partials/packer-plugin-sdk/multistep/commonsteps/HTTPConfig-not-required.mdx

@@ -34,4 +34,7 @@
 - `http_bind_address` (string) - This is the bind address for the HTTP server. Defaults to 0.0.0.0 so that
   it will work with any network interface.
 
+- `http_network_protocol` (string) - Defines the HTTP Network protocol. Valid options are `tcp`, `tcp4`, `tcp6`,
+  `unix`, and `unixpacket`. This value defaults to `tcp`.
+
 <!-- End of code generated from the comments of the HTTPConfig struct in multistep/commonsteps/http_config.go; -->

multistep/commonsteps/http_config.go

@@ -7,10 +7,20 @@ package commonsteps
 
 import (
 	"errors"
+	"fmt"
 
 	"github.com/hashicorp/packer-plugin-sdk/template/interpolate"
 )
 
+// These are the different valid network procotol values for "http_network_protocol"
+const (
+	NetworkProtocolTCP       string = "tcp"
+	NetworkProcotolTCP4             = "tcp4"
+	NetworkProtocolTCP6             = "tcp6"
+	NetworkProtocolUnix             = "unix"
+	NetworkProcotlUnixPacket        = "unixpacket"
+)
+
 // Packer will create an http server serving `http_directory` when it is set, a
 // random free port will be selected and the architecture of the directory
 // referenced will be available in your builder.
@@ -58,6 +68,9 @@ type HTTPConfig struct {
 	// interface with a non-loopback address. Either `http_bind_address` or
 	// `http_interface` can be specified.
 	HTTPInterface string `mapstructure:"http_interface" undocumented:"true"`
+	// Defines the HTTP Network protocol. Valid options are `tcp`, `tcp4`, `tcp6`,
+	// `unix`, and `unixpacket`. This value defaults to `tcp`.
+	HTTPNetworkProtocol string `mapstructure:"http_network_protocol"`
 }
 
 func (c *HTTPConfig) Prepare(ctx *interpolate.Context) []error {
@@ -91,5 +104,30 @@ func (c *HTTPConfig) Prepare(ctx *interpolate.Context) []error {
 			errors.New("http_content cannot be used in conjunction with http_dir. Consider using the file function to load file in memory and serve them with http_content: https://www.packer.io/docs/templates/hcl_templates/functions/file/file"))
 	}
 
+	if c.HTTPNetworkProtocol == "" {
+		c.HTTPNetworkProtocol = "tcp"
+	}
+
+	validProtocol := false
+	validProtocols := []string{
+		NetworkProtocolTCP,
+		NetworkProcotolTCP4,
+		NetworkProtocolTCP6,
+		NetworkProtocolUnix,
+		NetworkProcotlUnixPacket,
+	}
+
+	for _, protocol := range validProtocols {
+		if c.HTTPNetworkProtocol == protocol {
+			validProtocol = true
+			break
+		}
+	}
+
+	if !validProtocol {
+		errs = append(errs,
+			fmt.Errorf("http_network_protocol is invalid. Must be one of: %v", validProtocols))
+	}
+
 	return errs
 }

multistep/commonsteps/step_http_server.go

@@ -20,11 +20,12 @@ import (
 
 func HTTPServerFromHTTPConfig(cfg *HTTPConfig) *StepHTTPServer {
 	return &StepHTTPServer{
-		HTTPDir:     cfg.HTTPDir,
-		HTTPContent: cfg.HTTPContent,
-		HTTPPortMin: cfg.HTTPPortMin,
-		HTTPPortMax: cfg.HTTPPortMax,
-		HTTPAddress: cfg.HTTPAddress,
+		HTTPDir:             cfg.HTTPDir,
+		HTTPContent:         cfg.HTTPContent,
+		HTTPPortMin:         cfg.HTTPPortMin,
+		HTTPPortMax:         cfg.HTTPPortMax,
+		HTTPAddress:         cfg.HTTPAddress,
+		HTTPNetworkProcotol: cfg.HTTPNetworkProtocol,
 	}
 }
 
@@ -40,11 +41,12 @@ func HTTPServerFromHTTPConfig(cfg *HTTPConfig) *StepHTTPServer {
 //
 //	http_port int - The port the HTTP server started on.
 type StepHTTPServer struct {
-	HTTPDir     string
-	HTTPContent map[string]string
-	HTTPPortMin int
-	HTTPPortMax int
-	HTTPAddress string
+	HTTPDir             string
+	HTTPContent         map[string]string
+	HTTPPortMin         int
+	HTTPPortMax         int
+	HTTPAddress         string
+	HTTPNetworkProcotol string
 
 	l *net.Listener
 }
@@ -106,7 +108,7 @@ func (s *StepHTTPServer) Run(ctx context.Context, state multistep.StateBag) mult
 		Min:     s.HTTPPortMin,
 		Max:     s.HTTPPortMax,
 		Addr:    s.HTTPAddress,
-		Network: "tcp",
+		Network: s.HTTPNetworkProcotol,
 	}.Listen(ctx)
 
 	if err != nil {