diff --git a/doc/design/build_system/README.md b/doc/design/build_system/README.md index 310739f37ae48934afe1d042e87efef85b98f1fc..bf0e4dddc1b640ecbce489f65820aaf8a4b3b1e7 100644 --- a/doc/design/build_system/README.md +++ b/doc/design/build_system/README.md @@ -105,3 +105,48 @@ shared_library(api ### Implementation As above example CMakeLists.txt executes, each function invocation adds "nodes" to a dependency graph. It also use this graph to generate CMake commands including `add_executable`, `add_dependencies`, `target_link_libraries`, and `add_test`. + +### Using Package Manager For Go + +Building Go binaries and libraries need to satisfy their dependencies, generally +we can do `go get ./...` to download and compile all external dependencies. The +problems are: + +1. `go get` will always get the latest code from the default branch of the + remote repo, so changes of dependents might break the build. This is very + different with what we already have in `cmake/external` which download a + specific version or commit id of the dependency. +1. Some locations can not access external dependencies through the internet, as mentioned + in https://github.com/PaddlePaddle/Paddle/issues/2605. Using package management + tools can package the dependencies as a "vendor" package, which can be mirrored + at many cloud file hosting, so users what to compile paddle by themselves can + download this "vendor" package from a mirror site. + +#### Choose A Suitable Tool + +As mentioned by @wangkuiyi, [Here](https://github.com/golang/go/wiki/PackageManagementTools) +list dozens of Go package managers. We choose the tool using following principles: + +- Most "active" projects with more stars, more pull requests or commits +- Widely used project + +After comparing all these projects, we shall choose between the most popular +tools: Godep and Glide. + +Here's a brief comparison between Godep and Glide +: https://github.com/Masterminds/glide/wiki/Go-Package-Manager-Comparison. There are +also many complaints about using `Godep`. There's also a new "official" pakcage +management tool has been started at: https://github.com/golang/dep to resolve +such problems, but it's currently at Alpha stage. So the best choice now is +glide obviously. + +#### Manage Go Packages + +- Dependencies: `go/glide.yaml` will store the dependencies and their versions which + is directly imported by paddle. `go/glide.lock` will store all dependencies recursively + with their commit id. Builds will "lock" to these packages if we don't `glide up` + them +- Vendor package: `go/vendor` directory will generated when running `cmake` command. `cmake` + will download the code corresponding to `go/glide.lock`. If we put a vendor folder + under `go/`, cmake will just check the commit id to the packages under the folder, + if commit id matches, there will be no download at all.