From 1e5c432e1029601a664454388ae366ef69618d62 Mon Sep 17 00:00:00 2001 From: Christopher Speller Date: Mon, 25 Jun 2018 12:33:13 -0700 Subject: MM-10702 Moving plugins to use hashicorp go-plugin. (#8978) * Moving plugins to use hashicorp go-plugin. * Tweaks from feedback. --- .../github.com/hashicorp/go-plugin/rpc_server.go | 197 +++++++++++++++++++++ 1 file changed, 197 insertions(+) create mode 100644 vendor/github.com/hashicorp/go-plugin/rpc_server.go (limited to 'vendor/github.com/hashicorp/go-plugin/rpc_server.go') diff --git a/vendor/github.com/hashicorp/go-plugin/rpc_server.go b/vendor/github.com/hashicorp/go-plugin/rpc_server.go new file mode 100644 index 000000000..5bb18dd5d --- /dev/null +++ b/vendor/github.com/hashicorp/go-plugin/rpc_server.go @@ -0,0 +1,197 @@ +package plugin + +import ( + "errors" + "fmt" + "io" + "log" + "net" + "net/rpc" + "sync" + + "github.com/hashicorp/yamux" +) + +// RPCServer listens for network connections and then dispenses interface +// implementations over net/rpc. +// +// After setting the fields below, they shouldn't be read again directly +// from the structure which may be reading/writing them concurrently. +type RPCServer struct { + Plugins map[string]Plugin + + // Stdout, Stderr are what this server will use instead of the + // normal stdin/out/err. This is because due to the multi-process nature + // of our plugin system, we can't use the normal process values so we + // make our own custom one we pipe across. + Stdout io.Reader + Stderr io.Reader + + // DoneCh should be set to a non-nil channel that will be closed + // when the control requests the RPC server to end. + DoneCh chan<- struct{} + + lock sync.Mutex +} + +// ServerProtocol impl. +func (s *RPCServer) Init() error { return nil } + +// ServerProtocol impl. +func (s *RPCServer) Config() string { return "" } + +// ServerProtocol impl. +func (s *RPCServer) Serve(lis net.Listener) { + for { + conn, err := lis.Accept() + if err != nil { + log.Printf("[ERR] plugin: plugin server: %s", err) + return + } + + go s.ServeConn(conn) + } +} + +// ServeConn runs a single connection. +// +// ServeConn blocks, serving the connection until the client hangs up. +func (s *RPCServer) ServeConn(conn io.ReadWriteCloser) { + // First create the yamux server to wrap this connection + mux, err := yamux.Server(conn, nil) + if err != nil { + conn.Close() + log.Printf("[ERR] plugin: error creating yamux server: %s", err) + return + } + + // Accept the control connection + control, err := mux.Accept() + if err != nil { + mux.Close() + if err != io.EOF { + log.Printf("[ERR] plugin: error accepting control connection: %s", err) + } + + return + } + + // Connect the stdstreams (in, out, err) + stdstream := make([]net.Conn, 2) + for i, _ := range stdstream { + stdstream[i], err = mux.Accept() + if err != nil { + mux.Close() + log.Printf("[ERR] plugin: accepting stream %d: %s", i, err) + return + } + } + + // Copy std streams out to the proper place + go copyStream("stdout", stdstream[0], s.Stdout) + go copyStream("stderr", stdstream[1], s.Stderr) + + // Create the broker and start it up + broker := newMuxBroker(mux) + go broker.Run() + + // Use the control connection to build the dispenser and serve the + // connection. + server := rpc.NewServer() + server.RegisterName("Control", &controlServer{ + server: s, + }) + server.RegisterName("Dispenser", &dispenseServer{ + broker: broker, + plugins: s.Plugins, + }) + server.ServeConn(control) +} + +// done is called internally by the control server to trigger the +// doneCh to close which is listened to by the main process to cleanly +// exit. +func (s *RPCServer) done() { + s.lock.Lock() + defer s.lock.Unlock() + + if s.DoneCh != nil { + close(s.DoneCh) + s.DoneCh = nil + } +} + +// dispenseServer dispenses variousinterface implementations for Terraform. +type controlServer struct { + server *RPCServer +} + +// Ping can be called to verify the connection (and likely the binary) +// is still alive to a plugin. +func (c *controlServer) Ping( + null bool, response *struct{}) error { + *response = struct{}{} + return nil +} + +func (c *controlServer) Quit( + null bool, response *struct{}) error { + // End the server + c.server.done() + + // Always return true + *response = struct{}{} + + return nil +} + +// dispenseServer dispenses variousinterface implementations for Terraform. +type dispenseServer struct { + broker *MuxBroker + plugins map[string]Plugin +} + +func (d *dispenseServer) Dispense( + name string, response *uint32) error { + // Find the function to create this implementation + p, ok := d.plugins[name] + if !ok { + return fmt.Errorf("unknown plugin type: %s", name) + } + + // Create the implementation first so we know if there is an error. + impl, err := p.Server(d.broker) + if err != nil { + // We turn the error into an errors error so that it works across RPC + return errors.New(err.Error()) + } + + // Reserve an ID for our implementation + id := d.broker.NextId() + *response = id + + // Run the rest in a goroutine since it can only happen once this RPC + // call returns. We wait for a connection for the plugin implementation + // and serve it. + go func() { + conn, err := d.broker.Accept(id) + if err != nil { + log.Printf("[ERR] go-plugin: plugin dispense error: %s: %s", name, err) + return + } + + serve(conn, "Plugin", impl) + }() + + return nil +} + +func serve(conn io.ReadWriteCloser, name string, v interface{}) { + server := rpc.NewServer() + if err := server.RegisterName(name, v); err != nil { + log.Printf("[ERR] go-plugin: plugin dispense error: %s", err) + return + } + + server.ServeConn(conn) +} -- cgit v1.2.3-1-g7c22