aboutsummaryrefslogtreecommitdiff
path: root/vendor/google.golang.org/grpc/rpc_util.go
blob: 06544adbad6daa2ea365e219282f67f50a629c1e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
/*
 *
 * Copyright 2014, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

package grpc

import (
	"bytes"
	"compress/gzip"
	"encoding/binary"
	"fmt"
	"io"
	"io/ioutil"
	"math"
	"os"

	"github.com/golang/protobuf/proto"
	"golang.org/x/net/context"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/metadata"
	"google.golang.org/grpc/transport"
)

// Codec defines the interface gRPC uses to encode and decode messages.
type Codec interface {
	// Marshal returns the wire format of v.
	Marshal(v interface{}) ([]byte, error)
	// Unmarshal parses the wire format into v.
	Unmarshal(data []byte, v interface{}) error
	// String returns the name of the Codec implementation. The returned
	// string will be used as part of content type in transmission.
	String() string
}

// protoCodec is a Codec implemetation with protobuf. It is the default codec for gRPC.
type protoCodec struct{}

func (protoCodec) Marshal(v interface{}) ([]byte, error) {
	return proto.Marshal(v.(proto.Message))
}

func (protoCodec) Unmarshal(data []byte, v interface{}) error {
	return proto.Unmarshal(data, v.(proto.Message))
}

func (protoCodec) String() string {
	return "proto"
}

// Compressor defines the interface gRPC uses to compress a message.
type Compressor interface {
	// Do compresses p into w.
	Do(w io.Writer, p []byte) error
	// Type returns the compression algorithm the Compressor uses.
	Type() string
}

// NewGZIPCompressor creates a Compressor based on GZIP.
func NewGZIPCompressor() Compressor {
	return &gzipCompressor{}
}

type gzipCompressor struct {
}

func (c *gzipCompressor) Do(w io.Writer, p []byte) error {
	z := gzip.NewWriter(w)
	if _, err := z.Write(p); err != nil {
		return err
	}
	return z.Close()
}

func (c *gzipCompressor) Type() string {
	return "gzip"
}

// Decompressor defines the interface gRPC uses to decompress a message.
type Decompressor interface {
	// Do reads the data from r and uncompress them.
	Do(r io.Reader) ([]byte, error)
	// Type returns the compression algorithm the Decompressor uses.
	Type() string
}

type gzipDecompressor struct {
}

// NewGZIPDecompressor creates a Decompressor based on GZIP.
func NewGZIPDecompressor() Decompressor {
	return &gzipDecompressor{}
}

func (d *gzipDecompressor) Do(r io.Reader) ([]byte, error) {
	z, err := gzip.NewReader(r)
	if err != nil {
		return nil, err
	}
	defer z.Close()
	return ioutil.ReadAll(z)
}

func (d *gzipDecompressor) Type() string {
	return "gzip"
}

// callInfo contains all related configuration and information about an RPC.
type callInfo struct {
	failFast  bool
	headerMD  metadata.MD
	trailerMD metadata.MD
	traceInfo traceInfo // in trace.go
}

// CallOption configures a Call before it starts or extracts information from
// a Call after it completes.
type CallOption interface {
	// before is called before the call is sent to any server.  If before
	// returns a non-nil error, the RPC fails with that error.
	before(*callInfo) error

	// after is called after the call has completed.  after cannot return an
	// error, so any failures should be reported via output parameters.
	after(*callInfo)
}

type beforeCall func(c *callInfo) error

func (o beforeCall) before(c *callInfo) error { return o(c) }
func (o beforeCall) after(c *callInfo)        {}

type afterCall func(c *callInfo)

func (o afterCall) before(c *callInfo) error { return nil }
func (o afterCall) after(c *callInfo)        { o(c) }

// Header returns a CallOptions that retrieves the header metadata
// for a unary RPC.
func Header(md *metadata.MD) CallOption {
	return afterCall(func(c *callInfo) {
		*md = c.headerMD
	})
}

// Trailer returns a CallOptions that retrieves the trailer metadata
// for a unary RPC.
func Trailer(md *metadata.MD) CallOption {
	return afterCall(func(c *callInfo) {
		*md = c.trailerMD
	})
}

// The format of the payload: compressed or not?
type payloadFormat uint8

const (
	compressionNone payloadFormat = iota // no compression
	compressionMade
)

// parser reads complelete gRPC messages from the underlying reader.
type parser struct {
	// r is the underlying reader.
	// See the comment on recvMsg for the permissible
	// error types.
	r io.Reader

	// The header of a gRPC message. Find more detail
	// at http://www.grpc.io/docs/guides/wire.html.
	header [5]byte
}

// recvMsg reads a complete gRPC message from the stream.
//
// It returns the message and its payload (compression/encoding)
// format. The caller owns the returned msg memory.
//
// If there is an error, possible values are:
//   * io.EOF, when no messages remain
//   * io.ErrUnexpectedEOF
//   * of type transport.ConnectionError
//   * of type transport.StreamError
// No other error values or types must be returned, which also means
// that the underlying io.Reader must not return an incompatible
// error.
func (p *parser) recvMsg() (pf payloadFormat, msg []byte, err error) {
	if _, err := io.ReadFull(p.r, p.header[:]); err != nil {
		return 0, nil, err
	}

	pf = payloadFormat(p.header[0])
	length := binary.BigEndian.Uint32(p.header[1:])

	if length == 0 {
		return pf, nil, nil
	}
	// TODO(bradfitz,zhaoq): garbage. reuse buffer after proto decoding instead
	// of making it for each message:
	msg = make([]byte, int(length))
	if _, err := io.ReadFull(p.r, msg); err != nil {
		if err == io.EOF {
			err = io.ErrUnexpectedEOF
		}
		return 0, nil, err
	}
	return pf, msg, nil
}

// encode serializes msg and prepends the message header. If msg is nil, it
// generates the message header of 0 message length.
func encode(c Codec, msg interface{}, cp Compressor, cbuf *bytes.Buffer) ([]byte, error) {
	var b []byte
	var length uint
	if msg != nil {
		var err error
		// TODO(zhaoq): optimize to reduce memory alloc and copying.
		b, err = c.Marshal(msg)
		if err != nil {
			return nil, err
		}
		if cp != nil {
			if err := cp.Do(cbuf, b); err != nil {
				return nil, err
			}
			b = cbuf.Bytes()
		}
		length = uint(len(b))
	}
	if length > math.MaxUint32 {
		return nil, Errorf(codes.InvalidArgument, "grpc: message too large (%d bytes)", length)
	}

	const (
		payloadLen = 1
		sizeLen    = 4
	)

	var buf = make([]byte, payloadLen+sizeLen+len(b))

	// Write payload format
	if cp == nil {
		buf[0] = byte(compressionNone)
	} else {
		buf[0] = byte(compressionMade)
	}
	// Write length of b into buf
	binary.BigEndian.PutUint32(buf[1:], uint32(length))
	// Copy encoded msg to buf
	copy(buf[5:], b)

	return buf, nil
}

func checkRecvPayload(pf payloadFormat, recvCompress string, dc Decompressor) error {
	switch pf {
	case compressionNone:
	case compressionMade:
		if dc == nil || recvCompress != dc.Type() {
			return transport.StreamErrorf(codes.Unimplemented, "grpc: Decompressor is not installed for grpc-encoding %q", recvCompress)
		}
	default:
		return transport.StreamErrorf(codes.Internal, "grpc: received unexpected payload format %d", pf)
	}
	return nil
}

func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{}) error {
	pf, d, err := p.recvMsg()
	if err != nil {
		return err
	}
	if err := checkRecvPayload(pf, s.RecvCompress(), dc); err != nil {
		return err
	}
	if pf == compressionMade {
		d, err = dc.Do(bytes.NewReader(d))
		if err != nil {
			return transport.StreamErrorf(codes.Internal, "grpc: failed to decompress the received message %v", err)
		}
	}
	if err := c.Unmarshal(d, m); err != nil {
		return transport.StreamErrorf(codes.Internal, "grpc: failed to unmarshal the received message %v", err)
	}
	return nil
}

// rpcError defines the status from an RPC.
type rpcError struct {
	code codes.Code
	desc string
}

func (e rpcError) Error() string {
	return fmt.Sprintf("rpc error: code = %d desc = %s", e.code, e.desc)
}

// Code returns the error code for err if it was produced by the rpc system.
// Otherwise, it returns codes.Unknown.
func Code(err error) codes.Code {
	if err == nil {
		return codes.OK
	}
	if e, ok := err.(rpcError); ok {
		return e.code
	}
	return codes.Unknown
}

// ErrorDesc returns the error description of err if it was produced by the rpc system.
// Otherwise, it returns err.Error() or empty string when err is nil.
func ErrorDesc(err error) string {
	if err == nil {
		return ""
	}
	if e, ok := err.(rpcError); ok {
		return e.desc
	}
	return err.Error()
}

// Errorf returns an error containing an error code and a description;
// Errorf returns nil if c is OK.
func Errorf(c codes.Code, format string, a ...interface{}) error {
	if c == codes.OK {
		return nil
	}
	return rpcError{
		code: c,
		desc: fmt.Sprintf(format, a...),
	}
}

// toRPCErr converts an error into a rpcError.
func toRPCErr(err error) error {
	switch e := err.(type) {
	case rpcError:
		return err
	case transport.StreamError:
		return rpcError{
			code: e.Code,
			desc: e.Desc,
		}
	case transport.ConnectionError:
		return rpcError{
			code: codes.Internal,
			desc: e.Desc,
		}
	}
	return Errorf(codes.Unknown, "%v", err)
}

// convertCode converts a standard Go error into its canonical code. Note that
// this is only used to translate the error returned by the server applications.
func convertCode(err error) codes.Code {
	switch err {
	case nil:
		return codes.OK
	case io.EOF:
		return codes.OutOfRange
	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
		return codes.FailedPrecondition
	case os.ErrInvalid:
		return codes.InvalidArgument
	case context.Canceled:
		return codes.Canceled
	case context.DeadlineExceeded:
		return codes.DeadlineExceeded
	}
	switch {
	case os.IsExist(err):
		return codes.AlreadyExists
	case os.IsNotExist(err):
		return codes.NotFound
	case os.IsPermission(err):
		return codes.PermissionDenied
	}
	return codes.Unknown
}

// SupportPackageIsVersion2 is referenced from generated protocol buffer files
// to assert that that code is compatible with this version of the grpc package.
//
// This constant may be renamed in the future if a change in the generated code
// requires a synchronised update of grpc-go and protoc-gen-go. This constant
// should not be referenced from any other code.
const SupportPackageIsVersion2 = true