common/prpc, tools/cmd/cproto: prpc client

common/prpc/options.go

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package prpc
+
+import (
+        "fmt"
+        "time"
+
+        "google.golang.org/grpc"
+        "google.golang.org/grpc/metadata"
+
+        "github.com/luci/luci-go/common/retry"
+)
+
+// Options controls how RPC requests are sent.
+type Options struct {
+        Retry retry.Factory // RPC retrial.
+
+        // UserAgent is the value of User-Agent HTTP header.
+        // If empty, DefaultUserAgent is used.
+        UserAgent string
+        Insecure  bool // if true, use HTTP instead of HTTPS.
+
+        // the rest can be set only using CallOption.
+
+        resHeaderMetadata  *metadata.MD // destination for response HTTP headers.
+        resTrailerMetadata *metadata.MD // destination for response HTTP trailers.
+        serverDeadline     time.Duration
+}
+
+// DefaultOptions are used if no options are specified in Client.
+func DefaultOptions() *Options {
+        return &Options{
+                Retry: func() retry.Iterator {
+                        return &retry.ExponentialBackoff{
+                                Limited: retry.Limited{
+                                        Delay:   time.Second,
+                                        Retries: 5,
+                                },
+                        }
+                },
+        }
+}
+
+func (o *Options) apply(callOptions []grpc.CallOption) error {
+        for _, co := range callOptions {
+                prpcCo, ok := co.(CallOption)
+                if !ok {
+                        return fmt.Errorf("non-pRPC call option %T is used with pRPC client", co)
+                }
+                prpcCo.apply(o)
+        }
+        return nil
+}
+
+// CallOption mutates Options.
+type CallOption struct {
+        grpc.CallOption
+        // apply mutates options.
+        apply func(*Options)
+}
+
+// Header returns a CallOption that retrieves the header metadata.
+// Can be used instead of with grpc.Header.
+func Header(md *metadata.MD) *CallOption {
+        return &CallOption{
+                grpc.Header(md),
+                func(o *Options) {
+                        o.resHeaderMetadata = md
+                },
+        }
+}
+
+// Trailer returns a CallOption that retrieves the trailer metadata.
+// Can be used instead of grpc.Trailer.
+func Trailer(md *metadata.MD) *CallOption {
+        return &CallOption{
+                grpc.Trailer(md),
+                func(o *Options) {
+                        o.resTrailerMetadata = md
+                },
+        }
+}