由于 gRPC 以及依赖的第三方库都是托管在 Github 上，并且源码包总共加起来有 1GB 大小，众所周知，国内从 Github 下载源码速度慢且不稳定，过程令人抓狂。值得庆幸的是，码云(gitee.com)已对其中部分仓库作了镜像同步，每日自动同步一次，都在码云极速下载。因此，我们可借助 gitee.com 实现高速下载 gRPC 的相关源码，但下载时需要做一些适当的调整。操作如下。

  • 下载 grpc 源码

可通过 gitee.com 先下载 grpc 主框架源码

git clone git@gitee.com:mirrors/grpc.git
  • 修改 grpc 依赖的第三方库下载地址

进入前面下载的 grpc 主框架源码目录，修改 .gitmodules ，只需修改其中的 url 参数，其他保持不变，注意并非每个第三方库都在 gitee.com 上有镜像仓库，没有的保持不变。参考如下

➜  grpc-framework git:(786ebf69aa) ✗ more .gitmodules
[submodule "third_party/zlib"]
        path = third_party/zlib
        #url = https://github.com/madler/zlib.git
        url = https://gitee.com/mirrors/zlib.git
        # When using CMake to build, the zlib submodule ends up with a
        # generated file that makes Git consider the submodule dirty. This
        # state can be ignored for day-to-day development on gRPC.
        ignore = dirty
[submodule "third_party/protobuf"]
        path = third_party/protobuf
        url = https://github.com/google/protobuf.git
        #url = https://gitee.com/githubplus/protobuf.git
[submodule "third_party/gflags"]
        path = third_party/gflags
        # url = https://github.com/gflags/gflags.git
        url = https://gitee.com/mirrors/gflags.git
[submodule "third_party/googletest"]
        path = third_party/googletest
        # url = https://github.com/google/googletest.git
        url = https://gitee.com/mirrors/googletest.git
[submodule "third_party/benchmark"]
        path = third_party/benchmark
        url = https://github.com/google/benchmark
[submodule "third_party/boringssl-with-bazel"]
        path = third_party/boringssl-with-bazel
        # url = https://github.com/google/boringssl.git
        url = https://gitee.com/mirrors/boringssl.git
[submodule "third_party/cares/cares"]
        path = third_party/cares/cares
        # url = https://github.com/c-ares/c-ares.git
        url = https://gitee.com/mirrors/c-ares.git
        branch = cares-1_12_0
[submodule "third_party/bloaty"]
        path = third_party/bloaty
        # url = https://github.com/google/bloaty.git
        url = https://gitee.com/githubplus/bloaty.git
[submodule "third_party/abseil-cpp"]
        path = third_party/abseil-cpp
        # url = https://github.com/abseil/abseil-cpp.git
        url = https://gitee.com/mirrors/abseil-cpp.git
        branch = lts_2020_02_25
[submodule "third_party/envoy-api"]
        path = third_party/envoy-api
        url = https://github.com/envoyproxy/data-plane-api.git
        #url = https://gitee.com/githubplus/data-plane-api.git
[submodule "third_party/googleapis"]
        path = third_party/googleapis
        # url = https://github.com/googleapis/googleapis.git
        url = https://gitee.com/mirrors/googleapis.git
[submodule "third_party/protoc-gen-validate"]
        path = third_party/protoc-gen-validate
        # url = https://github.com/envoyproxy/protoc-gen-validate.git
        url = https://gitee.com/mirrors/protoc-gen-validate.git
[submodule "third_party/udpa"]
        path = third_party/udpa
        url = https://github.com/cncf/udpa.git
[submodule "third_party/libuv"]
        path = third_party/libuv
        # url = https://github.com/libuv/libuv.git
        url = https://gitee.com/mirrors/libuv.git

更新 git submodule 配置

git submodule sync

更新第三方库源码

git submodule update --init

特殊说明一下，我的 zlib 库一开始没有自动下载到 third_party/zlib 目录，导致后续 grpc 编译失败。重新调整了 .gitmodules ，临时注释了 ignore 参数，再重新更新第三方库，才下载到 zlib 库。grpc 会校验依赖的第三方库的版本是否兼容，因此，不要随便用旧版本的第三方库。 后续的 grpc 安装过程本文就不再详述。