75026f5e91
- Rename all instances to "shutdownCtx" to be really explicit. This context is special in that it can be closed at any time without warning, so it should be obvious to the reader. - Don't use shutdownCtx in RPC clients. Clients should not stop working immediately when shutdown is signalled, they need to keep working while the process is shutting down.
109 lines
3.0 KiB
Go
109 lines
3.0 KiB
Go
// Copyright (c) 2020 The Decred developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package rpc
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import (
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"context"
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"crypto/tls"
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"crypto/x509"
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"sync"
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"github.com/jrick/wsrpc/v2"
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)
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// Caller provides a client interface to perform JSON-RPC remote procedure calls.
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type Caller interface {
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// String returns the dialed URL.
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String() string
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// Call performs the remote procedure call defined by method and
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// waits for a response or a broken client connection.
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// Args provides positional parameters for the call.
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// Res must be a pointer to a struct, slice, or map type to unmarshal
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// a result (if any), or nil if no result is needed.
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Call(ctx context.Context, method string, res interface{}, args ...interface{}) error
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}
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// client wraps a wsrpc.Client, as well as all of the connection details
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// required to make a new client if the existing client is closed.
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type client struct {
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mu *sync.Mutex
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client *wsrpc.Client
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addr string
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tlsOpt wsrpc.Option
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authOpt wsrpc.Option
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notifier wsrpc.Notifier
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}
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func setup(user, pass, addr string, cert []byte, n wsrpc.Notifier) *client {
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// Create TLS options.
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pool := x509.NewCertPool()
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pool.AppendCertsFromPEM(cert)
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tc := &tls.Config{
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MinVersion: tls.VersionTLS12,
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CurvePreferences: []tls.CurveID{tls.X25519, tls.CurveP256},
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CipherSuites: []uint16{ // Only applies to TLS 1.2. TLS 1.3 ciphersuites are not configurable.
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tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
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tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
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tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
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tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
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tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
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tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
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},
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RootCAs: pool,
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}
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tlsOpt := wsrpc.WithTLSConfig(tc)
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// Create authentication options.
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authOpt := wsrpc.WithBasicAuth(user, pass)
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var mu sync.Mutex
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var c *wsrpc.Client
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fullAddr := "wss://" + addr + "/ws"
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return &client{&mu, c, fullAddr, tlsOpt, authOpt, n}
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}
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func (c *client) Close() {
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if c.client != nil {
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select {
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case <-c.client.Done():
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log.Tracef("RPC already closed (%s)", c.addr)
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default:
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if err := c.client.Close(); err != nil {
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log.Errorf("Failed to close RPC (%s): %v", c.addr, err)
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} else {
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log.Tracef("RPC closed (%s)", c.addr)
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}
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}
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}
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}
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// dial will return a connect rpc client if one exists, or attempt to create a
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// new one if not. A boolean indicates whether this connection is new (true), or
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// if it is an existing connection which is being reused (false).
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func (c *client) dial(ctx context.Context) (Caller, bool, error) {
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c.mu.Lock()
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defer c.mu.Unlock()
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if c.client != nil {
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select {
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case <-c.client.Done():
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log.Debugf("RPC client %s errored (%v); reconnecting...", c.addr, c.client.Err())
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c.client = nil
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default:
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return c.client, false, nil
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}
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}
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var err error
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c.client, err = wsrpc.Dial(ctx, c.addr, c.tlsOpt, c.authOpt, wsrpc.WithNotifier(c.notifier))
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if err != nil {
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return nil, false, err
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}
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return c.client, true, nil
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}
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