Build scripts that publish pre-compiled protoc artifacts

protoc is the compiler for .proto files. It generates language bindings for the messages and/or RPC services from .proto files.

Because protoc is a native executable, the scripts under this directory build and publish a protoc executable (a.k.a. artifact) to Maven repositories. The artifact can be used by build automation tools so that users would not need to compile and install protoc for their systems.

Versioning

The version of the protoc artifact must be the same as the version of the Protobuf project.

Artifact name

The name of a published protoc artifact is in the following format: protoc-<version>-<os>-<arch>.exe, e.g., protoc-3.0.0-alpha-3-windows-x86_64.exe.

System requirement

Install Apache Maven if you don't have it.

The scripts only work under Unix-like environments, e.g., Linux, MacOSX, and Cygwin or MinGW for Windows. Please see README.md of the Protobuf project for how to set up the build environment.

To install artifacts locally

The following command will install the protoc artifact to your local Maven repository.

$ mvn install

Cross-compilation

The Maven script will try to detect the OS and the architecture from Java system properties. It's possible to build a protoc binary for an architecture that is different from what Java has detected, as long as you have the proper compilers installed.

You can override the Maven properties os.detected.name and os.detected.arch to force the script to generate binaries for a specific OS and/or architecture. Valid values are defined as the return values of normalizeOs() and normalizeArch() of Detector from os-maven-plugin. Frequently used values are:

• os.detected.name: linux, osx, windows.
• os.detected.arch: x86_32, x86_64

For example, MingGW32 only ships with 32-bit compilers, but you can still build 32-bit protoc under 64-bit Windows, with the following command:

$ mvn install -Dos.detected.arch=x86_32

To push artifacts to Maven Central

Before you can upload artifacts to Maven Central repository, make sure you have read this page on how to configure GPG and Sonatype account.

You need to perform the deployment for every platform that you want to suppport. DO NOT close the staging repository until you have done the deployment for all platforms. Currently the following platforms are supported:

• Linux (x86_32 and x86_64)
• Windows (x86_32 and x86_64) with
• Cygwin with MinGW compilers (both x86_32 and x86_64)
• MSYS with MinGW32 (x86_32 only)
• MacOSX (x86_32 and x86_64)

Use the following command to deploy artifacts for the host platform to a staging repository.

$ mvn clean deploy -P release

It creates a new staging repository. Go to https://oss.sonatype.org/#stagingRepositories and find the repository, usually in the name like comgoogle-123.

You will want to run this command on a different platform. Remember, in subsequent deployments you will need to provide the repository name that you have found in the first deployment so that all artifacts go to the same repository:

$ mvn clean deploy -P release -Dstaging.repository=comgoogle-123

A 32-bit artifact can be deployed from a 64-bit host with -Dos.detected.arch=x86_32

When you have done deployment for all platforms, go to https://oss.sonatype.org/#stagingRepositories, verify that the staging repository has all the binaries, close and release this repository.

Tips for deploying on Windows

Under Windows the following error may occur: gpg: cannot open tty `no tty': No such file or directory. This can be fixed by configuring gpg through an active profile in .m2\settings.xml where also the Sonatype password is stored:

<settings>
  <servers>
    <server>
      <id>ossrh</id>
      <username>[username]</username>
      <password>[password]</password>
    </server>
  </servers>
  <profiles>
    <profile>
      <id>gpg</id>
      <properties>
        <gpg.executable>gpg</gpg.executable>
        <gpg.passphrase>[password]</gpg.passphrase>
      </properties>
    </profile>
  </profiles>
  <activeProfiles>
    <activeProfile>gpg</activeProfile>
  </activeProfiles>
</settings>

Tested build environments

We have succesfully built artifacts on the following environments:

• Linux x86_32 and x86_64: Ubuntu 14.04.2 64-bit
• Windows x86_32: MSYS with mingw32-gcc-g++ 4.8.1-4 on Windows 7 64-bit
• Windows x86_64: Cygwin64 with mingw64-x86_64-gcc-g++ 4.8.3-1 on Windows 7 64-bit
• Mac OS X x86_32 and x86_64: Mac OS X 10.9.5