add v2 directory (#59)

add v2 directory

This commit was generated by copying the contents of the parent directory into
the v2 directory.

This commit supercedes #58 and is one
of two in a series of commits to add Go module support to gax.

Unfortunately, gax-go already has a v2.0.0 tag. So, per [1] we create a v2/
subdirectory, copy all the v1 code, and create a v2 go.mod in the subdirectory.
Then, after this commit is merged, the commit will be tagged v2.0.1. This is a
combination of the "Major Branch" and the "Major Subdirectory" approaches
mentioned in [1].

1: https://github.com/golang/go/wiki/Modules#releasing-modules-v2-or-higher

v2/call_option.go

@@ -0,0 +1,157 @@
+// Copyright 2016, 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 gax
+
+import (
+	"math/rand"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// CallOption is an option used by Invoke to control behaviors of RPC calls.
+// CallOption works by modifying relevant fields of CallSettings.
+type CallOption interface {
+	// Resolve applies the option by modifying cs.
+	Resolve(cs *CallSettings)
+}
+
+// Retryer is used by Invoke to determine retry behavior.
+type Retryer interface {
+	// Retry reports whether a request should be retriedand how long to pause before retrying
+	// if the previous attempt returned with err. Invoke never calls Retry with nil error.
+	Retry(err error) (pause time.Duration, shouldRetry bool)
+}
+
+type retryerOption func() Retryer
+
+func (o retryerOption) Resolve(s *CallSettings) {
+	s.Retry = o
+}
+
+// WithRetry sets CallSettings.Retry to fn.
+func WithRetry(fn func() Retryer) CallOption {
+	return retryerOption(fn)
+}
+
+// OnCodes returns a Retryer that retries if and only if
+// the previous attempt returns a GRPC error whose error code is stored in cc.
+// Pause times between retries are specified by bo.
+//
+// bo is only used for its parameters; each Retryer has its own copy.
+func OnCodes(cc []codes.Code, bo Backoff) Retryer {
+	return &boRetryer{
+		backoff: bo,
+		codes:   append([]codes.Code(nil), cc...),
+	}
+}
+
+type boRetryer struct {
+	backoff Backoff
+	codes   []codes.Code
+}
+
+func (r *boRetryer) Retry(err error) (time.Duration, bool) {
+	st, ok := status.FromError(err)
+	if !ok {
+		return 0, false
+	}
+	c := st.Code()
+	for _, rc := range r.codes {
+		if c == rc {
+			return r.backoff.Pause(), true
+		}
+	}
+	return 0, false
+}
+
+// Backoff implements exponential backoff.
+// The wait time between retries is a random value between 0 and the "retry envelope".
+// The envelope starts at Initial and increases by the factor of Multiplier every retry,
+// but is capped at Max.
+type Backoff struct {
+	// Initial is the initial value of the retry envelope, defaults to 1 second.
+	Initial time.Duration
+
+	// Max is the maximum value of the retry envelope, defaults to 30 seconds.
+	Max time.Duration
+
+	// Multiplier is the factor by which the retry envelope increases.
+	// It should be greater than 1 and defaults to 2.
+	Multiplier float64
+
+	// cur is the current retry envelope
+	cur time.Duration
+}
+
+func (bo *Backoff) Pause() time.Duration {
+	if bo.Initial == 0 {
+		bo.Initial = time.Second
+	}
+	if bo.cur == 0 {
+		bo.cur = bo.Initial
+	}
+	if bo.Max == 0 {
+		bo.Max = 30 * time.Second
+	}
+	if bo.Multiplier < 1 {
+		bo.Multiplier = 2
+	}
+	// Select a duration between zero and the current max. It might seem counterintuitive to
+	// have so much jitter, but https://www.awsarchitectureblog.com/2015/03/backoff.html
+	// argues that that is the best strategy.
+	d := time.Duration(rand.Int63n(int64(bo.cur)))
+	bo.cur = time.Duration(float64(bo.cur) * bo.Multiplier)
+	if bo.cur > bo.Max {
+		bo.cur = bo.Max
+	}
+	return d
+}
+
+type grpcOpt []grpc.CallOption
+
+func (o grpcOpt) Resolve(s *CallSettings) {
+	s.GRPC = o
+}
+
+func WithGRPCOptions(opt ...grpc.CallOption) CallOption {
+	return grpcOpt(append([]grpc.CallOption(nil), opt...))
+}
+
+type CallSettings struct {
+	// Retry returns a Retryer to be used to control retry logic of a method call.
+	// If Retry is nil or the returned Retryer is nil, the call will not be retried.
+	Retry func() Retryer
+
+	// CallOptions to be forwarded to GRPC.
+	GRPC []grpc.CallOption
+}

v2/call_option_test.go

@@ -0,0 +1,88 @@
+// Copyright 2016, 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 gax
+
+import (
+	"testing"
+	"time"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+var _ Retryer = &boRetryer{}
+
+func TestBackofDefault(t *testing.T) {
+	backoff := Backoff{}
+
+	max := []time.Duration{1, 2, 4, 8, 16, 30, 30, 30, 30, 30}
+	for i, m := range max {
+		max[i] = m * time.Second
+	}
+
+	for i, w := range max {
+		if d := backoff.Pause(); d > w {
+			t.Errorf("Backoff duration should be at most %s, got %s", w, d)
+		} else if i < len(max)-1 && backoff.cur != max[i+1] {
+			t.Errorf("current envelope is %s, want %s", backoff.cur, max[i+1])
+		}
+	}
+}
+
+func TestBackoffExponential(t *testing.T) {
+	backoff := Backoff{Initial: 1, Max: 20, Multiplier: 2}
+	want := []time.Duration{1, 2, 4, 8, 16, 20, 20, 20, 20, 20}
+	for _, w := range want {
+		if d := backoff.Pause(); d > w {
+			t.Errorf("Backoff duration should be at most %s, got %s", w, d)
+		}
+	}
+}
+
+func TestOnCodes(t *testing.T) {
+	// Lint errors grpc.Errorf in 1.6. It mistakenly expects the first arg to Errorf to be a string.
+	errf := status.Errorf
+	apiErr := errf(codes.Unavailable, "")
+	tests := []struct {
+		c     []codes.Code
+		retry bool
+	}{
+		{nil, false},
+		{[]codes.Code{codes.DeadlineExceeded}, false},
+		{[]codes.Code{codes.DeadlineExceeded, codes.Unavailable}, true},
+		{[]codes.Code{codes.Unavailable}, true},
+	}
+	for _, tst := range tests {
+		b := OnCodes(tst.c, Backoff{})
+		if _, retry := b.Retry(apiErr); retry != tst.retry {
+			t.Errorf("retriable codes: %v, error: %s, retry: %t, want %t", tst.c, apiErr, retry, tst.retry)
+		}
+	}
+}

v2/gax.go

@@ -0,0 +1,38 @@
+// Copyright 2016, 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 gax contains a set of modules which aid the development of APIs
+// for clients and servers based on gRPC and Google API conventions.
+//
+// Application code will rarely need to use this library directly.
+// However, code generated automatically from API definition files can use it
+// to simplify code generation and to provide more convenient and idiomatic API surfaces.
+package gax
+
+const Version = "2.0.0"

v2/go.mod

@@ -0,0 +1,3 @@
+module github.com/googleapis/gax-go/v2
+
+require google.golang.org/grpc v1.16.0

v2/go.sum

@@ -0,0 +1,26 @@
+cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b h1:VKtxabqXZkF25pY9ekfRL6a582T4P37/31XEstQ5p58=
+github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
+github.com/golang/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:tluoj9z5200jBnyusfRPU2LqT6J+DAorxEvtC7LHB+E=
+github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
+github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+golang.org/x/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
+golang.org/x/net v0.0.0-20180826012351-8a410e7b638d h1:g9qWBGx4puODJTMVyoPrpoxPFgVGd+z1DZwjfRu4d0I=
+golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20180830151530-49385e6e1522 h1:Ve1ORMCxvRmSXBwJK+t3Oy+V2vRW2OetUQBq4rJIkZE=
+golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20180828015842-6cd1fcedba52/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
+google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8 h1:Nw54tB0rB7hY/N0NQvRW8DG4Yk3Q6T9cu9RcFQDu1tc=
+google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
+google.golang.org/grpc v1.16.0 h1:dz5IJGuC2BB7qXR5AyHNwAUBhZscK2xVez7mznh72sY=
+google.golang.org/grpc v1.16.0/go.mod h1:0JHn/cJsOMiMfNA9+DeHDlAU7KAAB5GDlYFpa9MZMio=
+honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

v2/header.go

@@ -0,0 +1,24 @@
+package gax
+
+import "bytes"
+
+// XGoogHeader is for use by the Google Cloud Libraries only.
+//
+// XGoogHeader formats key-value pairs.
+// The resulting string is suitable for x-goog-api-client header.
+func XGoogHeader(keyval ...string) string {
+	if len(keyval) == 0 {
+		return ""
+	}
+	if len(keyval)%2 != 0 {
+		panic("gax.Header: odd argument count")
+	}
+	var buf bytes.Buffer
+	for i := 0; i < len(keyval); i += 2 {
+		buf.WriteByte(' ')
+		buf.WriteString(keyval[i])
+		buf.WriteByte('/')
+		buf.WriteString(keyval[i+1])
+	}
+	return buf.String()[1:]
+}

v2/header_test.go

@@ -0,0 +1,19 @@
+package gax
+
+import "testing"
+
+func TestXGoogHeader(t *testing.T) {
+	for _, tst := range []struct {
+		kv   []string
+		want string
+	}{
+		{nil, ""},
+		{[]string{"abc", "def"}, "abc/def"},
+		{[]string{"abc", "def", "xyz", "123", "foo", ""}, "abc/def xyz/123 foo/"},
+	} {
+		got := XGoogHeader(tst.kv...)
+		if got != tst.want {
+			t.Errorf("Header(%q) = %q, want %q", tst.kv, got, tst.want)
+		}
+	}
+}