route/vendor/github.com/hashicorp/go-plugin/server.go

311 lines
7.9 KiB
Go
Raw Normal View History

2017-12-02 23:34:35 +00:00
package plugin
import (
"crypto/tls"
"encoding/base64"
"errors"
"fmt"
"io/ioutil"
"log"
"net"
"os"
"os/signal"
"runtime"
"strconv"
"sync/atomic"
"github.com/hashicorp/go-hclog"
"google.golang.org/grpc"
)
// CoreProtocolVersion is the ProtocolVersion of the plugin system itself.
// We will increment this whenever we change any protocol behavior. This
// will invalidate any prior plugins but will at least allow us to iterate
// on the core in a safe way. We will do our best to do this very
// infrequently.
const CoreProtocolVersion = 1
// HandshakeConfig is the configuration used by client and servers to
// handshake before starting a plugin connection. This is embedded by
// both ServeConfig and ClientConfig.
//
// In practice, the plugin host creates a HandshakeConfig that is exported
// and plugins then can easily consume it.
type HandshakeConfig struct {
// ProtocolVersion is the version that clients must match on to
// agree they can communicate. This should match the ProtocolVersion
// set on ClientConfig when using a plugin.
ProtocolVersion uint
// MagicCookieKey and value are used as a very basic verification
// that a plugin is intended to be launched. This is not a security
// measure, just a UX feature. If the magic cookie doesn't match,
// we show human-friendly output.
MagicCookieKey string
MagicCookieValue string
}
// ServeConfig configures what sorts of plugins are served.
type ServeConfig struct {
// HandshakeConfig is the configuration that must match clients.
HandshakeConfig
// TLSProvider is a function that returns a configured tls.Config.
TLSProvider func() (*tls.Config, error)
// Plugins are the plugins that are served.
Plugins map[string]Plugin
// GRPCServer should be non-nil to enable serving the plugins over
// gRPC. This is a function to create the server when needed with the
// given server options. The server options populated by go-plugin will
// be for TLS if set. You may modify the input slice.
//
// Note that the grpc.Server will automatically be registered with
// the gRPC health checking service. This is not optional since go-plugin
// relies on this to implement Ping().
GRPCServer func([]grpc.ServerOption) *grpc.Server
}
// Protocol returns the protocol that this server should speak.
func (c *ServeConfig) Protocol() Protocol {
result := ProtocolNetRPC
if c.GRPCServer != nil {
result = ProtocolGRPC
}
return result
}
// Serve serves the plugins given by ServeConfig.
//
// Serve doesn't return until the plugin is done being executed. Any
// errors will be outputted to os.Stderr.
//
// This is the method that plugins should call in their main() functions.
func Serve(opts *ServeConfig) {
// Validate the handshake config
if opts.MagicCookieKey == "" || opts.MagicCookieValue == "" {
fmt.Fprintf(os.Stderr,
"Misconfigured ServeConfig given to serve this plugin: no magic cookie\n"+
"key or value was set. Please notify the plugin author and report\n"+
"this as a bug.\n")
os.Exit(1)
}
// First check the cookie
if os.Getenv(opts.MagicCookieKey) != opts.MagicCookieValue {
fmt.Fprintf(os.Stderr,
"This binary is a plugin. These are not meant to be executed directly.\n"+
"Please execute the program that consumes these plugins, which will\n"+
"load any plugins automatically\n")
os.Exit(1)
}
// Logging goes to the original stderr
log.SetOutput(os.Stderr)
// internal logger to os.Stderr
logger := hclog.New(&hclog.LoggerOptions{
Level: hclog.Trace,
Output: os.Stderr,
JSONFormat: true,
})
// Create our new stdout, stderr files. These will override our built-in
// stdout/stderr so that it works across the stream boundary.
stdout_r, stdout_w, err := os.Pipe()
if err != nil {
fmt.Fprintf(os.Stderr, "Error preparing plugin: %s\n", err)
os.Exit(1)
}
stderr_r, stderr_w, err := os.Pipe()
if err != nil {
fmt.Fprintf(os.Stderr, "Error preparing plugin: %s\n", err)
os.Exit(1)
}
// Register a listener so we can accept a connection
listener, err := serverListener()
if err != nil {
logger.Error("plugin init error", "error", err)
return
}
// Close the listener on return. We wrap this in a func() on purpose
// because the "listener" reference may change to TLS.
defer func() {
listener.Close()
}()
var tlsConfig *tls.Config
if opts.TLSProvider != nil {
tlsConfig, err = opts.TLSProvider()
if err != nil {
logger.Error("plugin tls init", "error", err)
return
}
}
// Create the channel to tell us when we're done
doneCh := make(chan struct{})
// Build the server type
var server ServerProtocol
switch opts.Protocol() {
case ProtocolNetRPC:
// If we have a TLS configuration then we wrap the listener
// ourselves and do it at that level.
if tlsConfig != nil {
listener = tls.NewListener(listener, tlsConfig)
}
// Create the RPC server to dispense
server = &RPCServer{
Plugins: opts.Plugins,
Stdout: stdout_r,
Stderr: stderr_r,
DoneCh: doneCh,
}
case ProtocolGRPC:
// Create the gRPC server
server = &GRPCServer{
Plugins: opts.Plugins,
Server: opts.GRPCServer,
TLS: tlsConfig,
Stdout: stdout_r,
Stderr: stderr_r,
DoneCh: doneCh,
}
default:
panic("unknown server protocol: " + opts.Protocol())
}
// Initialize the servers
if err := server.Init(); err != nil {
logger.Error("protocol init", "error", err)
return
}
// Build the extra configuration
extra := ""
if v := server.Config(); v != "" {
extra = base64.StdEncoding.EncodeToString([]byte(v))
}
if extra != "" {
extra = "|" + extra
}
logger.Debug("plugin address", "network", listener.Addr().Network(), "address", listener.Addr().String())
// Output the address and service name to stdout so that core can bring it up.
fmt.Printf("%d|%d|%s|%s|%s%s\n",
CoreProtocolVersion,
opts.ProtocolVersion,
listener.Addr().Network(),
listener.Addr().String(),
opts.Protocol(),
extra)
os.Stdout.Sync()
// Eat the interrupts
ch := make(chan os.Signal, 1)
signal.Notify(ch, os.Interrupt)
go func() {
var count int32 = 0
for {
<-ch
newCount := atomic.AddInt32(&count, 1)
logger.Debug("plugin received interrupt signal, ignoring", "count", newCount)
}
}()
// Set our new out, err
os.Stdout = stdout_w
os.Stderr = stderr_w
// Accept connections and wait for completion
go server.Serve(listener)
<-doneCh
}
func serverListener() (net.Listener, error) {
if runtime.GOOS == "windows" {
return serverListener_tcp()
}
return serverListener_unix()
}
func serverListener_tcp() (net.Listener, error) {
minPort, err := strconv.ParseInt(os.Getenv("PLUGIN_MIN_PORT"), 10, 32)
if err != nil {
return nil, err
}
maxPort, err := strconv.ParseInt(os.Getenv("PLUGIN_MAX_PORT"), 10, 32)
if err != nil {
return nil, err
}
for port := minPort; port <= maxPort; port++ {
address := fmt.Sprintf("127.0.0.1:%d", port)
listener, err := net.Listen("tcp", address)
if err == nil {
return listener, nil
}
}
return nil, errors.New("Couldn't bind plugin TCP listener")
}
func serverListener_unix() (net.Listener, error) {
tf, err := ioutil.TempFile("", "plugin")
if err != nil {
return nil, err
}
path := tf.Name()
// Close the file and remove it because it has to not exist for
// the domain socket.
if err := tf.Close(); err != nil {
return nil, err
}
if err := os.Remove(path); err != nil {
return nil, err
}
l, err := net.Listen("unix", path)
if err != nil {
return nil, err
}
// Wrap the listener in rmListener so that the Unix domain socket file
// is removed on close.
return &rmListener{
Listener: l,
Path: path,
}, nil
}
// rmListener is an implementation of net.Listener that forwards most
// calls to the listener but also removes a file as part of the close. We
// use this to cleanup the unix domain socket on close.
type rmListener struct {
net.Listener
Path string
}
func (l *rmListener) Close() error {
// Close the listener itself
if err := l.Listener.Close(); err != nil {
return err
}
// Remove the file
return os.Remove(l.Path)
}