tec_grpc.hpp

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// Time-stamp: <Last changed 2026-02-07 23:40:43 by magnolia>
/*----------------------------------------------------------------------
------------------------------------------------------------------------
Copyright (c) 2020-2026 The Emacs Cat (https://github.com/olddeuteronomy/tec).
 
   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.
------------------------------------------------------------------------
----------------------------------------------------------------------*/
 
#pragma once
 
#include "tec/tec_def.hpp" // IWYU pragma: keep
#include "tec/tec_utils.hpp"
 
 
namespace tec {
 
 
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
*                      gRPC common parameters
*
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
static constexpr const int kGrpcMaxMessageSize{4};
 
 
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
*                       gRPC Server parameters
*
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
struct GrpcHealthCheckBuilder {
    void (*fptr)(bool);
};
 
struct GrpcReflectionBuilder {
    void (*fptr)(void);
};
 
 
struct GrpcServerParams {
    static constexpr const char kDefaultAddrUri[] = "0.0.0.0:50051";
 
    static constexpr const MilliSec kStartTimeout{Seconds{5}};
 
    static constexpr const MilliSec kShutdownTimeout{Seconds{10}};
 
    std::string addr_uri;      
    MilliSec start_timeout;    
    MilliSec shutdown_timeout; 
 
    // ServerBuilder parameters
    GrpcHealthCheckBuilder health_check_builder;  
    GrpcReflectionBuilder reflection_builder;     
    int max_message_size;                         
    int compression_algorithm;                    
    int compression_level;                        
 
    GrpcServerParams()
        : addr_uri{kDefaultAddrUri}
        , start_timeout{kStartTimeout}
        , shutdown_timeout{kShutdownTimeout}
        , health_check_builder{nullptr}
        , reflection_builder{nullptr}
        , max_message_size{kGrpcMaxMessageSize}
        , compression_algorithm{0}
        , compression_level{0}
        {}
};
 
 
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
*                   gRPC Client parameters
*
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
struct GrpcClientParams {
    static constexpr const char kDefaultAddrUri[] = "127.0.0.1:50051";
 
    static constexpr MilliSec kConnectTimeout{Seconds{5}};
 
    static constexpr MilliSec kCloseTimeout{Seconds{10}};
 
    std::string addr_uri;        
    MilliSec connect_timeout;    
    MilliSec close_timeout;      
 
    // Channel arguments
    int max_message_size;      
    int compression_algorithm; 
 
    GrpcClientParams()
        : addr_uri{kDefaultAddrUri}
        , connect_timeout{kConnectTimeout}
        , close_timeout{kCloseTimeout}
        , max_message_size{kGrpcMaxMessageSize}
        , compression_algorithm{0}
    {}
};
 
 
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *                  gRPC metadata on the client side
 *
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
template <typename TClientContext>
inline std::string get_server_metadata(const TClientContext& ctx, const std::string& key) {
    auto meta = ctx.GetServerInitialMetadata();
    auto data = meta.find(key);
    if( data != meta.end() ) {
        auto ref = data->second;  // grpc::string_ref
        auto len = ref.length();
        // NOTE: grpc::string_ref is NOT null-terminated string!
        if( len > 0 ) {
            return{ref.data(), 0, len};
        }
    }
    return{};
}
 
template <typename TClientContext>
inline void add_client_metadata(TClientContext& ctx, const std::string& key, const std::string& data) {
    ctx.AddMetadata(key, data);
}
 
 
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *                  gRPC metadata on the server side
 *
 *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
template <typename TServerContext>
inline std::string get_client_metadata(const TServerContext* pctx, const std::string& key) {
    auto meta = pctx->client_metadata();
    auto data = meta.find(key);
    if( data != meta.end() ) {
        auto ref = data->second;  // grpc::string_ref
        auto len = ref.length();
        // NOTE: grpc::string_ref is NOT null-terminated string!
        if( len > 0 ) {
            return{ref.data(), 0, len};
        }
    }
    return{};
}
 
template <typename TServerContext>
inline void add_server_medadata(TServerContext* pctx, const std::string& key, const std::string& data) {
    pctx->AddInitialMetadata(key, data);
}
 
 
} // ::tec