mirror of https://github.com/grpc/grpc.git
The C based gRPC (C++, Python, Ruby, Objective-C, PHP, C#)
https://grpc.io/
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175 lines
7.1 KiB
175 lines
7.1 KiB
# Regenerating project files |
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Prerequisites: `python`, `pip install mako` |
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``` |
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# Regenerate the projects files using templates |
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tools/buildgen/generate_projects.sh |
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``` |
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# Quick justification |
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We've approached the problem of the build system from a lot of different |
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angles. The main issue was that there isn't a single build system that |
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was going to single handedly cover all of our usage cases. |
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So instead we decided to work the following way: |
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* A `build.yaml` file at the root is the source of truth for listing all the |
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targets and files needed to build grpc and its tests, as well as a basic system |
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for dependency description. |
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* Each project file (Makefile, Visual Studio project files, Bazel's BUILD) is |
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a [YAML](http://yaml.org) file used by the `build.yaml` file to generate the |
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final output file. |
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This way we can maintain as many project system as we see fit, without having |
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to manually maintain them when we add or remove new code to the repository. |
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Only the structure of the project file is relevant to the template. The actual |
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list of source code and targets isn't. |
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We currently have template files for GNU Make, Visual Studio 2013, |
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[Bazel](http://bazel.io) and [gyp](https://gyp.gsrc.io/) (albeit only for |
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Node.js). In the future, we |
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would like to expand to also generate [cmake](https://cmake.org) |
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project files, XCode project files, and an Android.mk file allowing to compile |
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gRPC using Android's NDK. |
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We'll gladly accept contribution that'd create additional project files |
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using that system. |
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# Structure of `build.yaml` |
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The `build.yaml` file has the following structure: |
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``` |
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settings: # global settings, such as version number |
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... |
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filegroups: # groups of files that are automatically expanded |
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... |
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libs: # list of libraries to build |
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... |
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target: # list of targets to build |
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... |
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``` |
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The `filegroups` are helpful to re-use a subset of files in multiple targets. |
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One `filegroups` entry has the following structure: |
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``` |
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- name: "arbitrary string", # the name of the filegroup |
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public_headers: # list of public headers defined in that filegroup |
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- ... |
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headers: # list of headers defined in that filegroup |
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- ... |
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src: # list of source files defined in that filegroup |
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- ... |
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``` |
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The `libs` collection contains the list of all the libraries we describe. Some may be |
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helper libraries for the tests. Some may be installable libraries. Some may be |
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helper libraries for installable binaries. |
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The `targets` array contains the list of all the binary targets we describe. Some may |
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be installable binaries. |
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One `libs` or `targets` entry has the following structure (see below for |
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details): |
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``` |
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name: "arbitrary string", # the name of the library |
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build: "build type", # in which situation we want that library to be |
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# built and potentially installed (see below). |
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language: "...", # the language tag; "c" or "c++" |
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public_headers: # list of public headers to install |
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headers: # list of headers used by that target |
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src: # list of files to compile |
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secure: boolean, # see below |
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baselib: boolean, # this is a low level library that has system |
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# dependencies |
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vs_project_guid: '{...}', # Visual Studio's unique guid for that project |
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filegroups: # list of filegroups to merge to that project |
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# note that this will be expanded automatically |
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deps: # list of libraries this target depends on |
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deps_linkage: "..." # "static" or "dynamic". Used by the Makefile only to |
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# determine the way dependencies are linkned. Defaults |
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# to "dynamic". |
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dll: "..." # see below. |
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dll_def: "..." # Visual Studio's dll definition file. |
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vs_props: # List of property sheets to attach to that project. |
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vs_config_type: "..." # DynamicLibrary/StaticLibrary. Used only when |
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# creating a library. Specifies if we're building a |
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# static library or a dll. Use in conjunction with `dll_def`. |
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vs_packages: # List of nuget packages this project depends on. |
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``` |
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## The `"build"` tag |
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Currently, the "`build`" tag have these meanings: |
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* `"all"`: library to build on `"make all"`, and install on the system. |
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* `"protoc"`: a protoc plugin to build on `"make all"` and install on the system. |
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* `"private"`: a library to only build for tests. |
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* `"test"`: a test binary to run on `"make test"`. |
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* `"tool"`: a binary to be built upon `"make tools"`. |
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All of the targets should always be present in the generated project file, if |
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possible and applicable. But the build tag is what should group the targets |
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together in a single build command. |
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## The `"secure"` tag |
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This means this target requires OpenSSL one way or another. The values can be |
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`"yes"`, `"no"` and `"check"`. The default value is `"check"`. It means that |
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the target requires OpenSSL, but that since the target depends on another one |
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that is supposed to also import OpenSSL, the import should then be implicitely |
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transitive. `"check"` should then only disable that target if OpenSSL hasn't |
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been found or is unavailable. |
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## The `"baselib"` boolean |
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This means this is a library that will provide most of the features for gRPC. |
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In particular, if we're locally building OpenSSL, protobuf or zlib, then we |
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should merge OpenSSL, protobuf or zlib inside that library. That effect depends |
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on the `"language"` tag. OpenSSL and zlib are for `"c"` libraries, while |
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protobuf is for `"c++"` ones. |
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## The `"dll"` tag |
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Used only by Visual Studio's project files. "true" means the project will be |
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built with both static and dynamic runtimes. "false" means it'll only be built |
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with static runtime. "only" means it'll only be built with the dll runtime. |
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## The `"dll_def"` tag |
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Specifies the visual studio's dll definition file. When creating a DLL, you |
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sometimes (not always) need a def file (see grpc.def). |
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# The template system |
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We're currently using the [mako templates](http://www.makotemplates.org/) |
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renderer. That choice enables us to simply render text files without dragging |
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with us a lot of other features. Feel free to explore the current templates |
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in that directory. The simplest one is probably [BUILD.template](BUILD.template) |
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which is used to create the [Bazel](http://bazel.io/) project file. |
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## The renderer engine |
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As mentioned, the renderer is using [mako templates](http://www.makotemplates.org/), |
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but some glue is needed to process all of that. See the [buildgen folder](../tools/buildgen) |
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for more details. We're mainly loading the build.json file, and massaging it, |
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in order to get the list of properties we need, into a Python dictionary, that |
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is then passed to the template while rending it. |
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## The plugins |
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The file build.json itself isn't passed straight to the template files. It is |
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first processed and modified by a few plugins. For example, the `filegroups` |
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expander is [a plugin](../tools/buildgen/plugins/expand_filegroups.py). |
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The structure of a plugin is simple. The plugin must defined the function |
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`mako_plugin` that takes a Python dictionary. That dictionary represents the |
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current state of the build.json contents. The plugin can alter it to whatever |
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feature it needs to add.
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