Building is only necessary if you are making changes to gRPC-Java or testing/using a non-released version (e.g. master HEAD) of gRPC-Java library.
Building requires JDK 8, as our tests use TLS.
grpc-java has a C++ code generation plugin for protoc. Since many Java developers don‘t have C compilers installed and don’t need to run or modify the codegen, the build can skip it. To skip, create the file <project-root>/gradle.properties and add skipCodegen=true.
Some parts of grpc-java depend on Android. Since many Java developers don‘t have the Android SDK installed and don’t need to run or modify the Android components, the build can skip it. To skip, create the file <project-root>/gradle.properties and add skipAndroid=true.
Then, to build, run:
$ ./gradlew build
To install the artifacts to your Maven local repository for use in your own project, run:
$ ./gradlew publishToMavenLocal
Building in IntelliJ works best when you import the project as a Gradle project and delegate IDE build/run actions to Gradle.
You can find this setting at:
-> Build Tools -> Gradle -> Runner -> Delegate IDE build/run actions to gradle.
This section is only necessary if you are making changes to the code generation. Most users only need to use skipCodegen=true as discussed above.
The codegen plugin is C++ code and requires protobuf 3.17.2 or later.
For Linux, Mac and MinGW:
$ PROTOBUF_VERSION=3.17.2 $ curl -LO https://github.com/protocolbuffers/protobuf/releases/download/v$PROTOBUF_VERSION/protobuf-all-$PROTOBUF_VERSION.tar.gz $ tar xzf protobuf-all-$PROTOBUF_VERSION.tar.gz $ cd protobuf-$PROTOBUF_VERSION $ ./configure --disable-shared $ make # You may want to pass -j to make this run faster; see make --help $ sudo make install
If you are comfortable with C++ compilation and autotools, you can specify a --prefix for Protobuf and use -I in CXXFLAGS, -L in LDFLAGS to reference it. The environment variables will be used when building grpc-java.
Protobuf installs to /usr/local by default.
For Visual C++, please refer to the Protobuf README for how to compile Protobuf. gRPC-java assumes a Release build.
Some versions of Mac OS X (e.g., 10.10) doesn't have /usr/local in the default search paths for header files and libraries. It will fail the build of the codegen. To work around this, you will need to set environment variables:
$ export CXXFLAGS="-I/usr/local/include" LDFLAGS="-L/usr/local/lib"
When building on Windows and VC++, you need to specify project properties for Gradle to find protobuf:
.\gradlew publishToMavenLocal ^
-PvcProtobufInclude=C:\path\to\protobuf\src ^
-PvcProtobufLibs=C:\path\to\protobuf\vsprojects\Release ^
-PtargetArch=x86_32
Since specifying those properties every build is bothersome, you can instead create <project-root>\gradle.properties with contents like:
vcProtobufInclude=C:\\path\\to\\protobuf\\src vcProtobufLibs=C:\\path\\to\\protobuf\\vsprojects\\Release targetArch=x86_32
By default, the build script will build the codegen for the same architecture as the Java runtime installed on your system. If you are using 64-bit JVM, the codegen will be compiled for 64-bit. Since Protobuf is only built for 32-bit by default, the targetArch=x86_32 is necessary.
If you have both MinGW and VC++ installed on Windows, VC++ will be used by default. To override this default and use MinGW, add -PvcDisable=true to your Gradle command line or add vcDisable=true to your <project-root>\gradle.properties.
The build script pulls pre-compiled protoc from Maven Central by default. We have built protoc binaries for popular systems, but they may not work for your system. If protoc cannot be downloaded or would not run, you can use the one that has been built by your own, by adding this property to <project-root>/gradle.properties:
protoc=/path/to/protoc
This section is only necessary if you are building modules depending on Android (e.g., cronet). Non-Android users only need to use skipAndroid=true as discussed above.
Download and install Android Studio from Android Developer site. You can find the configuration for Android SDK at:
Preferences -> System Settings -> Android SDK
Select the version of Android SDK to be installed and click apply. The location of Android SDK being installed is shown at Android SDK Location at the same panel. The default is $HOME/Library/Android/sdk for Mac OS and $HOME/Android/Sdk for Linux. You can change this to a custom location.
Go to Android SDK and navigate to Command line tools only. Download and unzip the package for your build machine OS into somewhere easy to find (e.g., $HOME/Android/sdk). This will be your Android SDK home directory. The Android SDK Manager tool is in tools/bin/sdkmanager.
Run the sdkmanager tool:
$ tools/bin/sdkmanager --update $ tools/bin/sdkmanager "platforms;android-28"
This installs Android SDK 28 into platforms/android-28 of your Android SDK home directory. More usage of sdkmanager can be found at Android User Guide.
After Android SDK is installed, you need to set the ANDROID_HOME environment variable to your Android SDK home directory:
$ export ANDROID_HOME=<path-to-your-android-sdk>