Abseil Quickstart (Python)

This quick tutorial will get you up and running with Python Abseil. Please see the Programming Guides for details about specific modules.

Prerequisites

Running the Abseil code within this tutorial requires the following:

• A compatible platform (e.g. Windows, Mac OS X, Linux, etc.). Most platforms are fully supported.
• Python 2 or 3.
• pip
• Git for interacting with the Abseil source code repository, which is contained on GitHub. To install Git, consult the Set Up Git guide on GitHub.

Note: this Quickstart uses Bazel as the official build system for Abseil, which is supported on most major platforms (Linux, Windows, MacOS, for example) and compilers. The Abseil source code assumes you are using Bazel and contains `BUILD.bazel` files for that purpose.

To install the Abseil Python package, simply run:

pip install absl-py

Or you can install from source via the instructions on github.

Creating and Running a Script

Here’s an example hello.py script that takes a user name and an optional integer specifying the number of times to print the greeting.

from absl import app
from absl import flags

FLAGS = flags.FLAGS
flags.DEFINE_string("name", None, "Your name.")
flags.DEFINE_integer("num_times", 1,
                     "Number of times to print greeting.")

# Required flag.
flags.mark_flag_as_required("name")

def main(argv):
  del argv  # Unused.
  for i in range(0, FLAGS.num_times):
    print('Hello, %s!' % FLAGS.name)


if __name__ == '__main__':
  app.run(main)

Running with Bazel

Now you can build and run your script using Bazel. To do this, you will need a WORKSPACE file (simply adding an empty file named WORKSPACE in your Bazel base directory is fine for this exercise) and a BUILD file with this build rule:

py_binary(
  name = "hello",
  deps = [],
  srcs = ["hello.py"],
)

You can then build and run your target:

$ cd /WORKSPACE_ROOT/
$ bazel build :hello
..................

$ bazel-bin/hello --name=Daenerys
Hello, Daenerys!

Or alternatively you can run your application via a single run command:

$ bazel run :hello --name=Daenerys

For more information about Bazel Python Build Rules, consult the Bazel Documentation for Python

What’s Next

• See the Programming Guides for details about specific modules.