feat: add hostname-suffix option to config-ssh (#17270)

spikecurtis · web-flow · commit 59c5bc9bd2dd · 2025-04-07T12:11:04.000+04:00
Adds `hostname-suffix` as a Config SSH option that we get from Coderd, and also accept via a CLI flag.

It doesn't actually do anything with this value --- that's for PRs up the stack, since we need the `coder ssh` command to be updated to understand the suffix first.
diff --git a/cli/configssh.go b/cli/configssh.go
@@ -45,8 +45,10 @@ const (
 // sshConfigOptions represents options that can be stored and read
 // from the coder config in ~/.ssh/coder.
 type sshConfigOptions struct {
-	waitEnum         string
+	waitEnum string
+	// Deprecated: moving away from prefix to hostnameSuffix
 	userHostPrefix   string
+	hostnameSuffix   string
 	sshOptions       []string
 	disableAutostart bool
 	header           []string
@@ -97,7 +99,11 @@ func (o sshConfigOptions) equal(other sshConfigOptions) bool {
 	if !slicesSortedEqual(o.header, other.header) {
 		return false
 	}
-	return o.waitEnum == other.waitEnum && o.userHostPrefix == other.userHostPrefix && o.disableAutostart == other.disableAutostart && o.headerCommand == other.headerCommand
+	return o.waitEnum == other.waitEnum &&
+		o.userHostPrefix == other.userHostPrefix &&
+		o.disableAutostart == other.disableAutostart &&
+		o.headerCommand == other.headerCommand &&
+		o.hostnameSuffix == other.hostnameSuffix
 }
 
 // slicesSortedEqual compares two slices without side-effects or regard to order.
@@ -119,6 +125,9 @@ func (o sshConfigOptions) asList() (list []string) {
 	if o.userHostPrefix != "" {
 		list = append(list, fmt.Sprintf("ssh-host-prefix: %s", o.userHostPrefix))
 	}
+	if o.hostnameSuffix != "" {
+		list = append(list, fmt.Sprintf("hostname-suffix: %s", o.hostnameSuffix))
+	}
 	if o.disableAutostart {
 		list = append(list, fmt.Sprintf("disable-autostart: %v", o.disableAutostart))
 	}
@@ -314,6 +323,10 @@ func (r *RootCmd) configSSH() *serpent.Command {
 				// Override with user flag.
 				coderdConfig.HostnamePrefix = sshConfigOpts.userHostPrefix
 			}
+			if sshConfigOpts.hostnameSuffix != "" {
+				// Override with user flag.
+				coderdConfig.HostnameSuffix = sshConfigOpts.hostnameSuffix
+			}
 
 			// Write agent configuration.
 			defaultOptions := []string{
@@ -518,6 +531,12 @@ func (r *RootCmd) configSSH() *serpent.Command {
 			Description: "Override the default host prefix.",
 			Value:       serpent.StringOf(&sshConfigOpts.userHostPrefix),
 		},
+		{
+			Flag:        "hostname-suffix",
+			Env:         "CODER_CONFIGSSH_HOSTNAME_SUFFIX",
+			Description: "Override the default hostname suffix.",
+			Value:       serpent.StringOf(&sshConfigOpts.hostnameSuffix),
+		},
 		{
 			Flag:        "wait",
 			Env:         "CODER_CONFIGSSH_WAIT", // Not to be mixed with CODER_SSH_WAIT.
@@ -568,6 +587,9 @@ func sshConfigWriteSectionHeader(w io.Writer, addNewline bool, o sshConfigOption
 	if o.userHostPrefix != "" {
 		_, _ = fmt.Fprintf(&ow, "# :%s=%s\n", "ssh-host-prefix", o.userHostPrefix)
 	}
+	if o.hostnameSuffix != "" {
+		_, _ = fmt.Fprintf(&ow, "# :%s=%s\n", "hostname-suffix", o.hostnameSuffix)
+	}
 	if o.disableAutostart {
 		_, _ = fmt.Fprintf(&ow, "# :%s=%v\n", "disable-autostart", o.disableAutostart)
 	}
@@ -607,6 +629,8 @@ func sshConfigParseLastOptions(r io.Reader) (o sshConfigOptions) {
 				o.waitEnum = parts[1]
 			case "ssh-host-prefix":
 				o.userHostPrefix = parts[1]
+			case "hostname-suffix":
+				o.hostnameSuffix = parts[1]
 			case "ssh-option":
 				o.sshOptions = append(o.sshOptions, parts[1])
 			case "disable-autostart":
diff --git a/cli/configssh_test.go b/cli/configssh_test.go
@@ -432,6 +432,7 @@ func TestConfigSSH_FileWriteAndOptionsFlow(t *testing.T) {
 						"# Last config-ssh options:",
 						"# :wait=yes",
 						"# :ssh-host-prefix=coder-test.",
+						"# :hostname-suffix=coder-suffix",
 						"# :header=X-Test-Header=foo",
 						"# :header=X-Test-Header2=bar",
 						"# :header-command=printf h1=v1 h2=\"v2\" h3='v3'",
@@ -447,6 +448,7 @@ func TestConfigSSH_FileWriteAndOptionsFlow(t *testing.T) {
 				"--yes",
 				"--wait=yes",
 				"--ssh-host-prefix", "coder-test.",
+				"--hostname-suffix", "coder-suffix",
 				"--header", "X-Test-Header=foo",
 				"--header", "X-Test-Header2=bar",
 				"--header-command", "printf h1=v1 h2=\"v2\" h3='v3'",
diff --git a/cli/testdata/coder_config-ssh_--help.golden b/cli/testdata/coder_config-ssh_--help.golden
@@ -33,6 +33,9 @@ OPTIONS:
           unix-like shell. This flag forces the use of unix file paths (the
           forward slash '/').
 
+      --hostname-suffix string, $CODER_CONFIGSSH_HOSTNAME_SUFFIX
+          Override the default hostname suffix.
+
       --ssh-config-file string, $CODER_SSH_CONFIG_FILE (default: ~/.ssh/config)
           Specifies the path to an SSH config.
 
diff --git a/docs/reference/cli/config-ssh.md b/docs/reference/cli/config-ssh.md
