Add publisher-subscriber example

README.md

@@ -13,6 +13,9 @@ distributed as Debian packages.
 
 API documentation is available at [pkg.go.dev][docs].
 
+An example module with a publisher and a subscriber can be found in
+[examples/publisher_subscriber](examples/publisher_subscriber).
+
 ### ROS 2 interface bindings
 
 rclgo requires Go bindings of all the ROS 2 interfaces to exist. rclgo-gen is
@@ -36,12 +39,12 @@ import _ "github.com/tiiuae/rclgo/cmd/rclgo-gen"
 ```
 Then run `go mod tidy`. This version of rclgo-gen can be used by running
 
-    go run github.com/tiiuae/rclgo/cmd/rclgo-gen generate -d msgs
+    go run github.com/tiiuae/rclgo/cmd/rclgo-gen generate -d msgs --include-go-package-deps ./...
 
 in the project directory. The command can be added as a `go generate` comment to
 one of the source files in the project, such as `main.go`, as follows:
 ```go
-//go:generate go run github.com/tiiuae/rclgo/cmd/rclgo-gen generate -d msgs
+//go:generate go run github.com/tiiuae/rclgo/cmd/rclgo-gen generate -d msgs --include-go-package-deps ./...
 ```
 
 ### Developing with custom interface types

examples/examples_test.go

@@ -15,9 +15,17 @@ func skipIfShort(t *testing.T) {
 	}
 }
 
+const shellPrelude = `
+set -eo pipefail
+function kill-jobs {
+	kill $(jobs -p)
+}
+trap 'kill-jobs' SIGINT SIGTERM EXIT
+`
+
 func shell(t *testing.T, script string) {
 	t.Helper()
-	cmd := exec.Command("bash", "-c", script)
+	cmd := exec.Command("bash", "-c", shellPrelude+script)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	require.NoError(t, cmd.Run())
@@ -26,12 +34,6 @@ func shell(t *testing.T, script string) {
 func TestCustomMessagePackage(t *testing.T) {
 	skipIfShort(t)
 	shell(t, `
-set -e
-function kill-jobs {
-	kill $(jobs -p)
-}
-trap 'kill-jobs' SIGINT SIGTERM EXIT
-
 cd custom_message_package/greeting_msgs
 rm -rf build install log
 colcon build
@@ -47,3 +49,33 @@ msg=$(ros2 topic echo --once /greeter/hello greeting_msgs/msg/Hello)
 test "$msg" == $'name: gopher\n---'
 `)
 }
+
+func TestPublisherSubscriber(t *testing.T) {
+	skipIfShort(t)
+	shell(t, `
+cd publisher_subscriber
+rm -rf msgs pub sub pipe
+go generate
+
+go build -o pub ./publisher
+go build -o sub ./subscriber
+
+./pub &
+
+mkfifo pipe
+./sub >pipe 2>&1 &
+
+function check_output {
+	received_msg='Received: &std_msgs_msg.String{Data:"gopher"}'
+	while read -r line; do
+		if [[ "$line" == *"$received_msg"* ]]; then
+			exit 0
+		fi
+	done <pipe
+	exit 1
+}
+export -f check_output
+
+timeout 3 bash -c 'check_output'
+`)
+}

examples/publisher_subscriber/.gitignore

@@ -0,0 +1,4 @@
+/msgs
+/pub
+/sub
+/pipe

examples/publisher_subscriber/README.md

@@ -0,0 +1,12 @@
+# Publisher-subscriber example
+
+This is an example of a publisher and subscriber.
+
+To run the example, generate Go bindings by running
+
+    go generate
+
+Then you can run the publisher and subscriber in separate terminals:
+
+    go run ./publisher
+    go run ./subscriber

examples/publisher_subscriber/cgo-flags.env

@@ -0,0 +1,2 @@
+export CGO_CFLAGS='-I/opt/ros/humble/include/action_msgs -I/opt/ros/humble/include/builtin_interfaces -I/opt/ros/humble/include/rcl -I/opt/ros/humble/include/rcl_action -I/opt/ros/humble/include/rcl_yaml_param_parser -I/opt/ros/humble/include/rcutils -I/opt/ros/humble/include/rmw -I/opt/ros/humble/include/rosidl_runtime_c -I/opt/ros/humble/include/rosidl_typesupport_interface -I/opt/ros/humble/include/std_msgs -I/opt/ros/humble/include/unique_identifier_msgs '
+export CGO_LDFLAGS='-L/opt/ros/humble/lib -Wl,-rpath=/opt/ros/humble/lib '

examples/publisher_subscriber/generate.go

@@ -0,0 +1,3 @@
+package main
+
+//go:generate go run github.com/tiiuae/rclgo/cmd/rclgo-gen generate -d msgs --include-go-package-deps ./...

examples/publisher_subscriber/go.mod

@@ -0,0 +1,36 @@
+module github.com/tiiuae/rclgo/examples/publisher_subscriber
+
+go 1.20
+
+// This is needed to keep the version of rclgo automatically in sync with the
+// rest of the repository. It is in general not needed for modules outside
+// this repository.
+replace github.com/tiiuae/rclgo v0.0.0 => ../..
+
+require github.com/tiiuae/rclgo v0.0.0
+
+require (
+	github.com/alessio/shellescape v1.4.2 // indirect
+	github.com/fsnotify/fsnotify v1.6.0 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/kivilahtio/go-re v0.1.8 // indirect
+	github.com/magiconair/properties v1.8.7 // indirect
+	github.com/mitchellh/go-homedir v1.1.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/pelletier/go-toml/v2 v2.0.8 // indirect
+	github.com/spf13/afero v1.9.5 // indirect
+	github.com/spf13/cast v1.5.1 // indirect
+	github.com/spf13/cobra v1.7.0 // indirect
+	github.com/spf13/jwalterweatherman v1.1.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/spf13/viper v1.16.0 // indirect
+	github.com/subosito/gotenv v1.4.2 // indirect
+	golang.org/x/exp v0.0.0-20230811145659-89c5cff77bcb // indirect
+	golang.org/x/mod v0.11.0 // indirect
+	golang.org/x/sys v0.8.0 // indirect
+	golang.org/x/text v0.9.0 // indirect
+	golang.org/x/tools v0.9.1 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)