1 // Copyright 2022 gRPC authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include "src/core/config/load_config.h"
16
17 #include <grpc/support/port_platform.h>
18 #include <stdio.h>
19
20 #include "absl/flags/marshalling.h"
21 #include "absl/log/check.h"
22 #include "absl/strings/numbers.h"
23 #include "absl/strings/str_join.h"
24 #include "absl/types/optional.h"
25 #include "src/core/util/env.h"
26
27 namespace grpc_core {
28
29 namespace {
LoadEnv(absl::string_view environment_variable)30 absl::optional<std::string> LoadEnv(absl::string_view environment_variable) {
31 return GetEnv(std::string(environment_variable).c_str());
32 }
33 } // namespace
34
LoadConfigFromEnv(absl::string_view environment_variable,const char * default_value)35 std::string LoadConfigFromEnv(absl::string_view environment_variable,
36 const char* default_value) {
37 CHECK(!environment_variable.empty());
38 return LoadEnv(environment_variable).value_or(default_value);
39 }
40
LoadConfigFromEnv(absl::string_view environment_variable,int32_t default_value)41 int32_t LoadConfigFromEnv(absl::string_view environment_variable,
42 int32_t default_value) {
43 auto env = LoadEnv(environment_variable);
44 if (env.has_value()) {
45 int32_t out;
46 if (absl::SimpleAtoi(*env, &out)) return out;
47 fprintf(stderr, "Error reading int from %s: '%s' is not a number",
48 std::string(environment_variable).c_str(), env->c_str());
49 }
50 return default_value;
51 }
52
LoadConfigFromEnv(absl::string_view environment_variable,bool default_value)53 bool LoadConfigFromEnv(absl::string_view environment_variable,
54 bool default_value) {
55 auto env = LoadEnv(environment_variable);
56 if (env.has_value()) {
57 bool out;
58 std::string error;
59 if (absl::ParseFlag(env->c_str(), &out, &error)) return out;
60 fprintf(stderr, "Error reading bool from %s: '%s' is not a bool: %s",
61 std::string(environment_variable).c_str(), env->c_str(),
62 error.c_str());
63 }
64 return default_value;
65 }
66
LoadConfig(const absl::Flag<std::vector<std::string>> & flag,absl::string_view environment_variable,const absl::optional<std::string> & override,const char * default_value)67 std::string LoadConfig(const absl::Flag<std::vector<std::string>>& flag,
68 absl::string_view environment_variable,
69 const absl::optional<std::string>& override,
70 const char* default_value) {
71 if (override.has_value()) return *override;
72 auto from_flag = absl::GetFlag(flag);
73 if (!from_flag.empty()) return absl::StrJoin(from_flag, ",");
74 return LoadConfigFromEnv(environment_variable, default_value);
75 }
76
77 } // namespace grpc_core
78