site/docs/bazel-container.md

---
layout: documentation
title: Bazel container
---

# Getting Started with Bazel Docker Container

This page provides details on the contents of the Bazel container, how to build
the [abseil-cpp](https://github.com/abseil/abseil-cpp) project using Bazel
inside the Bazel container, and how to build this project directly
from the host machine using the Bazel container with directory mounting.

## Build Abseil project from your host machine with directory mounting

The instructions in this section allow you to build using the Bazel container
with the sources checked out in your host environment. A container is started up
for each build command you execute. Build results are cached in your host
environment so they can be reused across builds.

Clone the project to a directory in your host machine.

```bash
git clone https://github.com/abseil/abseil-cpp.git /src/workspace
```

Create a folder that will have cached results to be shared across builds.

```bash
mkdir -p /tmp/build_output/
```

Use the Bazel container to build the project and make the build
outputs available in the output folder in your host machine.

```bash
docker run \
  -e USER="$(id -u)" \
  -u="$(id -u)" \
  -v /src/workspace:/src/workspace \
  -v /tmp/build_output:/tmp/build_output \
  -w /src/workspace \
  l.gcr.io/google/bazel:latest \
  --output_user_root=/tmp/build_output \
  build //absl/...
```

Build the project with sanitizers by adding the --config=<asan/tsan/msan> build
flag to select AddressSanitizer (asan), ThreadSanitizer (tsan) or
MemorySanitizer (msan) accordingly.

```bash
docker run \
  -e USER="$(id -u)" \
  -u="$(id -u)" \
  -v /src/workspace:/src/workspace \
  -v /tmp/build_output:/tmp/build_output \
  -w /src/workspace \
  l.gcr.io/google/bazel:latest \
  --output_user_root=/tmp/build_output \
  build --config=<asan/tsan/msan> -- //absl/... -//absl/types:variant_test
```

## Build Abseil project from inside the container

The instructions in this section allow you to build using the Bazel container
with the sources inside the container. By starting a container at the beginning
of your developement workflow and doing changes in the worskpace within the
container, build results will be cached.

Start a shell in the Bazel container:

```bash
docker run --interactive --entrypoint=/bin/bash l.gcr.io/google/bazel:latest
```

Each container id is unique. In the instructions bellow, the container was 5a99103747c6.

Clone the project.

```bash
root@5a99103747c6:~# git clone https://github.com/abseil/abseil-cpp.git && cd abseil-cpp/
```

Do a regular build.

```bash
root@5a99103747c6:~/abseil-cpp# bazel build //absl/...
```

Build the project with sanitizers by adding the `--config=<asan/tsan/msan>` build
flag to select AddressSanitizer (asan), ThreadSanitizer (tsan) or
MemorySanitizer (msan) accordingly.

```bash
root@5a99103747c6:~/abseil-cpp# bazel build --config=<asan/tsan/msan> -- //absl/... -//absl/types:variant_test
```

## Explore the Bazel container

If you haven't already, start an interactive shell inside the Bazel container.

```bash
docker run -it --entrypoint=/bin/bash l.gcr.io/google/bazel:latest
root@5a99103747c6:/#
```

Explore the container contents.

```bash
root@5a99103747c6:/# clang --version
clang version 8.0.0 (trunk 340178)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin

root@5a99103747c6:/# java -version
openjdk version "1.8.0_181"
OpenJDK Runtime Environment (build 1.8.0_181-8u181-b13-0ubuntu0.16.04.1-b13)
OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode)

root@5a99103747c6:/# python -V
Python 2.7.12

root@5a99103747c6:/# python3 -V
Python 3.6.6

root@5a99103747c6:/# bazel version
Extracting Bazel installation...
Build label: 0.17.1
Build target: bazel-out/k8-opt/bin/src/main/java/com/google/devtools/build/lib/bazel/BazelServer_deploy.jar
Build time: Fri Sep 14 10:39:25 2018 (1536921565)
Build timestamp: 1536921565
Build timestamp as int: 1536921565
```