Add --host and -H as equivalent options to --url

Docker supports -H and --host for specify the listening socket. Podman
should support them also in order to match the CLI.

These will not be documented since Podman defaults to using the
--url option.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

cmd/podman/registry/remote.go

@@ -31,11 +31,11 @@ func IsRemote() bool {
 		fs.SetInterspersed(false)
 		fs.BoolVarP(&remoteFromCLI.Value, "remote", "r", remote, "")
 		connectionFlagName := "connection"
-		ignoredConnection := ""
-		fs.StringVarP(&ignoredConnection, connectionFlagName, "c", "", "")
+		fs.StringP(connectionFlagName, "c", "", "")
+		hostFlagName := "host"
+		fs.StringP(hostFlagName, "H", "", "")
 		urlFlagName := "url"
-		ignoredURL := ""
-		fs.StringVar(&ignoredURL, urlFlagName, "", "")
+		fs.String(urlFlagName, "", "")
 
 		// The shell completion logic will call a command called "__complete" or "__completeNoDesc"
 		// This command will always be the second argument
@@ -46,7 +46,7 @@ func IsRemote() bool {
 		}
 		_ = fs.Parse(os.Args[start:])
 		// --connection or --url implies --remote
-		remoteFromCLI.Value = remoteFromCLI.Value || fs.Changed(connectionFlagName) || fs.Changed(urlFlagName)
+		remoteFromCLI.Value = remoteFromCLI.Value || fs.Changed(connectionFlagName) || fs.Changed(urlFlagName) || fs.Changed(hostFlagName)
 	})
 	return podmanOptions.EngineMode == entities.TunnelMode || remoteFromCLI.Value
 }

cmd/podman/root.go

@@ -345,6 +345,8 @@ func rootFlags(cmd *cobra.Command, opts *entities.PodmanConfig) {
 	urlFlagName := "url"
 	lFlags.StringVar(&opts.URI, urlFlagName, uri, "URL to access Podman service (CONTAINER_HOST)")
 	_ = cmd.RegisterFlagCompletionFunc(urlFlagName, completion.AutocompleteDefault)
+	lFlags.StringVarP(&opts.URI, "host", "H", uri, "Used for Docker compatibility")
+	_ = lFlags.MarkHidden("host")
 
 	// Context option added just for compatibility with DockerCLI.
 	lFlags.String("context", "default", "Name of the context to use to connect to the daemon (This flag is a NOOP and provided solely for scripting compatibility.)")

test/system/250-systemd.bats

@@ -400,4 +400,23 @@ EOF
     run_podman rm -f -t 0 $cname
 }
 
+@test "podman-system-service containers --host" {
+    skip_if_remote "N/A under podman-remote"
+
+    SERVICE_NAME=podman-service-$(random_string)
+    port=$(random_free_port)
+    URL=tcp://127.0.0.1:$port
+
+    systemd-run --unit=$SERVICE_NAME $PODMAN system service $URL --time=0
+    wait_for_port 127.0.0.1 $port
+
+    run_podman --host $URL run --rm $IMAGE true
+    run_podman -H $URL run --rm $IMAGE true
+
+    systemctl stop $SERVICE_NAME
+
+    # Make sure the option is actually connecting
+    run_podman 125 --host $URL run --rm $IMAGE true
+    assert "$output" =~ "Cannot connect to Podman.*connection refused"
+}
 # vim: filetype=sh