credentials_impl.h

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/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef GRPCPP_SECURITY_CREDENTIALS_IMPL_H
#define GRPCPP_SECURITY_CREDENTIALS_IMPL_H

#include <map>
#include <memory>
#include <vector>

#include <grpc/grpc_security_constants.h>
#include <grpcpp/channel_impl.h>
#include <grpcpp/impl/codegen/client_interceptor.h>
#include <grpcpp/impl/codegen/grpc_library.h>
#include <grpcpp/security/auth_context.h>
#include <grpcpp/support/channel_arguments_impl.h>
#include <grpcpp/support/status.h>
#include <grpcpp/support/string_ref.h>

struct grpc_call;

namespace grpc_impl {

class ChannelCredentials;
class CallCredentials;
class SecureCallCredentials;
class SecureChannelCredentials;

std::shared_ptr<Channel> CreateCustomChannelImpl(
    const grpc::string& target,
    const std::shared_ptr<ChannelCredentials>& creds,
    const ChannelArguments& args);

namespace experimental {
std::shared_ptr<Channel> CreateCustomChannelWithInterceptors(
    const grpc::string& target,
    const std::shared_ptr<ChannelCredentials>& creds,
    const ChannelArguments& args,
    std::vector<
        std::unique_ptr<grpc::experimental::ClientInterceptorFactoryInterface>>
        interceptor_creators);
}

class ChannelCredentials : private grpc::GrpcLibraryCodegen {
 public:
  ChannelCredentials();
  ~ChannelCredentials();

 protected:
  friend std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
      const std::shared_ptr<ChannelCredentials>& channel_creds,
      const std::shared_ptr<CallCredentials>& call_creds);

  virtual SecureChannelCredentials* AsSecureCredentials() = 0;

 private:
  friend std::shared_ptr<Channel> CreateCustomChannelImpl(
      const grpc::string& target,
      const std::shared_ptr<ChannelCredentials>& creds,
      const ChannelArguments& args);

  friend std::shared_ptr<Channel>
  grpc_impl::experimental::CreateCustomChannelWithInterceptors(
      const grpc::string& target,
      const std::shared_ptr<ChannelCredentials>& creds,
      const ChannelArguments& args,
      std::vector<std::unique_ptr<
          grpc::experimental::ClientInterceptorFactoryInterface>>
          interceptor_creators);

  virtual std::shared_ptr<Channel> CreateChannelImpl(
      const grpc::string& target, const ChannelArguments& args) = 0;

  // This function should have been a pure virtual function, but it is
  // implemented as a virtual function so that it does not break API.
  virtual std::shared_ptr<Channel> CreateChannelWithInterceptors(
      const grpc::string& target, const ChannelArguments& args,
      std::vector<std::unique_ptr<
          grpc::experimental::ClientInterceptorFactoryInterface>>
          interceptor_creators) {
    return nullptr;
  }
};

class CallCredentials : private grpc::GrpcLibraryCodegen {
 public:
  CallCredentials();
  ~CallCredentials();

  virtual bool ApplyToCall(grpc_call* call) = 0;

 protected:
  friend std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
      const std::shared_ptr<ChannelCredentials>& channel_creds,
      const std::shared_ptr<CallCredentials>& call_creds);

  friend std::shared_ptr<CallCredentials> CompositeCallCredentials(
      const std::shared_ptr<CallCredentials>& creds1,
      const std::shared_ptr<CallCredentials>& creds2);

  virtual SecureCallCredentials* AsSecureCredentials() = 0;
};

struct SslCredentialsOptions {
  grpc::string pem_root_certs;

  grpc::string pem_private_key;

  grpc::string pem_cert_chain;
};

// Factories for building different types of Credentials The functions may
// return empty shared_ptr when credentials cannot be created. If a
// Credentials pointer is returned, it can still be invalid when used to create
// a channel. A lame channel will be created then and all rpcs will fail on it.

std::shared_ptr<ChannelCredentials> GoogleDefaultCredentials();

std::shared_ptr<ChannelCredentials> SslCredentials(
    const SslCredentialsOptions& options);

std::shared_ptr<CallCredentials> GoogleComputeEngineCredentials();

constexpr long kMaxAuthTokenLifetimeSecs = 3600;

std::shared_ptr<CallCredentials> ServiceAccountJWTAccessCredentials(
    const grpc::string& json_key,
    long token_lifetime_seconds = grpc_impl::kMaxAuthTokenLifetimeSecs);

std::shared_ptr<CallCredentials> GoogleRefreshTokenCredentials(
    const grpc::string& json_refresh_token);

std::shared_ptr<CallCredentials> AccessTokenCredentials(
    const grpc::string& access_token);

std::shared_ptr<CallCredentials> GoogleIAMCredentials(
    const grpc::string& authorization_token,
    const grpc::string& authority_selector);

std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
    const std::shared_ptr<ChannelCredentials>& channel_creds,
    const std::shared_ptr<CallCredentials>& call_creds);

std::shared_ptr<CallCredentials> CompositeCallCredentials(
    const std::shared_ptr<CallCredentials>& creds1,
    const std::shared_ptr<CallCredentials>& creds2);

std::shared_ptr<ChannelCredentials> InsecureChannelCredentials();

class MetadataCredentialsPlugin {
 public:
  virtual ~MetadataCredentialsPlugin() {}

  virtual bool IsBlocking() const { return true; }

  virtual const char* GetType() const { return ""; }

  virtual grpc::Status GetMetadata(
      grpc::string_ref service_url, grpc::string_ref method_name,
      const grpc::AuthContext& channel_auth_context,
      std::multimap<grpc::string, grpc::string>* metadata) = 0;
};

std::shared_ptr<CallCredentials> MetadataCredentialsFromPlugin(
    std::unique_ptr<MetadataCredentialsPlugin> plugin);

namespace experimental {

struct StsCredentialsOptions {
  grpc::string token_exchange_service_uri;  // Required.
  grpc::string resource;                    // Optional.
  grpc::string audience;                    // Optional.
  grpc::string scope;                       // Optional.
  grpc::string requested_token_type;        // Optional.
  grpc::string subject_token_path;          // Required.
  grpc::string subject_token_type;          // Required.
  grpc::string actor_token_path;            // Optional.
  grpc::string actor_token_type;            // Optional.
};

grpc::Status StsCredentialsOptionsFromJson(const grpc::string& json_string,
                                           StsCredentialsOptions* options);

grpc::Status StsCredentialsOptionsFromEnv(StsCredentialsOptions* options);

std::shared_ptr<CallCredentials> StsCredentials(
    const StsCredentialsOptions& options);

struct AltsCredentialsOptions {
  std::vector<grpc::string> target_service_accounts;
};

std::shared_ptr<ChannelCredentials> AltsCredentials(
    const AltsCredentialsOptions& options);

std::shared_ptr<ChannelCredentials> LocalCredentials(
    grpc_local_connect_type type);

}  // namespace experimental
}  // namespace grpc_impl

#endif  // GRPCPP_SECURITY_CREDENTIALS_IMPL_H