vendor/google.golang.org/grpc/internal/envconfig/envconfig.go

   1 /*
   2  *
   3  * Copyright 2018 gRPC authors.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  *
  17  */
  18
  19 // Package envconfig contains grpc settings configured by environment variables.
  20 package envconfig
  21
  22 import (
  23         "os"
  24         "strings"
  25 )
  26
  27 const (
  28         prefix              = "GRPC_GO_"
  29         retryStr            = prefix + "RETRY"
  30         requireHandshakeStr = prefix + "REQUIRE_HANDSHAKE"
  31 )
  32
  33 // RequireHandshakeSetting describes the settings for handshaking.
  34 type RequireHandshakeSetting int
  35
  36 const (
  37         // RequireHandshakeHybrid (default, deprecated) indicates to not wait for
  38         // handshake before considering a connection ready, but wait before
  39         // considering successful.
  40         RequireHandshakeHybrid RequireHandshakeSetting = iota
  41         // RequireHandshakeOn (default after the 1.17 release) indicates to wait
  42         // for handshake before considering a connection ready/successful.
  43         RequireHandshakeOn
  44         // RequireHandshakeOff indicates to not wait for handshake before
  45         // considering a connection ready/successful.
  46         RequireHandshakeOff
  47 )
  48
  49 var (
  50         // Retry is set if retry is explicitly enabled via "GRPC_GO_RETRY=on".
  51         Retry = strings.EqualFold(os.Getenv(retryStr), "on")
  52         // RequireHandshake is set based upon the GRPC_GO_REQUIRE_HANDSHAKE
  53         // environment variable.
  54         //
  55         // Will be removed after the 1.18 release.
  56         RequireHandshake RequireHandshakeSetting
  57 )
  58
  59 func init() {
  60         switch strings.ToLower(os.Getenv(requireHandshakeStr)) {
  61         case "on":
  62         default:
  63                 RequireHandshake = RequireHandshakeOn
  64         case "off":
  65                 RequireHandshake = RequireHandshakeOff
  66         case "hybrid":
  67                 // Will be removed after the 1.17 release.
  68                 RequireHandshake = RequireHandshakeHybrid
  69         }
  70 }