func main() {
services := []struct {
uri string
svc host.Service
}{
// Examples
{
"/core/examples",
host.NewFactoryServiceContext(&host.ExampleFactoryService{}),
},
// Examples
{
"/core/ping",
host.NewPingService(),
},
}
var err error
flag.Parse()
glog.Infof("Started with %s", os.Args[1:])
h := host.NewServiceHost()
err = h.Initialize(bindAddress.String())
if err != nil {
glog.Fatalf("Error initializing: %s\n", err)
}
ctx := operation.SetAuthorizationToken(context.Background(), authToken)
_, err = host.GetServiceHostManagementState(ctx)
if err != nil {
glog.Fatalf("Error getting ServiceHostState: %s\n", err)
}
var ops []*operation.Operation
for _, s := range services {
op := operation.NewPost(ctx, uri.Extend(uri.Empty(), s.uri), nil)
ops = append(ops, op)
h.StartService(op, s.svc)
}
_, err = operation.Join(ops)
if err != nil {
glog.Fatalf("Error starting services: %s", err)
}
start(h)
}
// ServeHTTP implements the host's core http entry point.
func (h *ServiceHost) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
ctx := context.Background()
op := operation.NewOperation(ctx)
op.SetRequest(req)
if glog.V(xenon.Debug) {
glog.Infof("host: %s %s", req.Method, req.URL.Path)
}
// Create context for handling this request. The request associated with
// this operation might complete long before the workflow that it kicked
// off completes. This workflow needs to flow parameters such as those
// related to authorization to other operations and workflows.
// On the Java side this is solved by using thread locals that are carefully
// set when an operation is handled, making sure they can automatically be
// flowed to newly created operations. On the Go side there is no equivalent
// for thread locals so this context has to be passed around explicitly.
if t := req.Header.Get(operation.RequestAuthTokenHeader); t != "" {
ctx = operation.SetAuthorizationToken(ctx, t)
}
// Operations may be marked complete before this function returns.
// Handle the request in a separate routine to return to the client ASAP.
op.Start()
go h.HandleRequest(ctx, op)
if err := op.Wait(); err != nil {
if handler, ok := err.(http.Handler); ok {
if glog.V(xenon.Debug) {
glog.Warningf("host: %s %s: custom error handler", req.Method, req.URL.Path)
}
handler.ServeHTTP(rw, req)
return
}
body := &common.ServiceErrorResponse{
Message: err.Error(),
}
op.SetStatusCode(http.StatusInternalServerError)
op.SetBody(body)
}
// Default status code to 200 OK
code := op.GetStatusCode()
if code == 0 {
code = http.StatusOK
}
if glog.V(xenon.Debug) {
glog.Infof("host: %s %s: status %d", req.Method, req.URL.Path, code)
}
if !op.IsStreamResponse() {
rw.Header().Set(operation.ContentType, operation.ApplicationJSON)
}
rw.WriteHeader(code)
if err := op.EncodeBody(rw); err != nil && err != operation.ErrBodyNotSet {
glog.Warningf("host: failure writing body: %s\n", err)
}
}