website2/docs/compiling-overview.md

---
id: compiling-overview
title: Compiling Heron
sidebar_label: Compiling Overview
---
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Heron is currently available for [Mac OS X 10.14](compiling-osx),
[Ubuntu 18.04](compiling-linux), and [Debian10](compiling-docker#building-heron).
 This guide describes the basics of the
Heron build system. For step-by-step build instructions for other platforms,
the following guides are available:

* [Building on Linux Platforms](compiling-linux)
* [Building on Mac OS X](compiling-osx)

Heron can be built either [in its entirety](#building-all-components), as [individual components](#building-specific-components).

Instructions on running unit tests for Heron can also be found in [Testing Heron](compiling-running-tests).

## Requirements

You must have the following installed to compile Heron:

* [Bazel](http://bazel.io/docs/install.html) = {{% bazelVersion %}}. Later
  versions might work but have not been tested. See [Installing Bazel](#installing-bazel)below.
* [Java 11](https://www.oracle.com/java/technologies/javase-jdk11-downloads.html)
  is required by Bazel and Heron;
  topologies can be written in Java 7 or above
  , but Heron jars are required to run with a Java 11 JRE.
* [Autoconf](http://www.gnu.org/software/autoconf/autoconf.html) >=
  2.6.3
* [Automake](https://www.gnu.org/software/automake/) >= 1.11.1
* [GNU Make](https://www.gnu.org/software/make/) >= 3.81
* [GNU Libtool](http://www.gnu.org/software/libtool/) >= 2.4.6
* [gcc/g++](https://gcc.gnu.org/) >= 4.8.1 (Linux platforms)
* [CMake](https://cmake.org/) >= 2.6.4
* [Python](https://www.python.org/) >= 3.4
* [Perl](https://www.perl.org/) >= 5.8.8
* [Ant] (https://ant.apache.org/) >= 1.10.0
* [CppUnit] (https://freedesktop.org/wiki/Software/cppunit/) >= 1.10.1
* [Pkg-Config] (https://www.freedesktop.org/wiki/Software/pkg-config/) >= 0.29.2

Export the `CC` and `CXX` environment variables with a path specific to your
machine:

```bash
$ export CC=/your-path-to/bin/c_compiler
$ export CXX=/your-path-to/bin/c++_compiler
$ echo $CC $CXX
```

## Installing Bazel

Heron uses the [Bazel](http://bazel.io) build tool. Bazel releases can be found here:
https://github.com/bazelbuild/bazel/releases/tag/{{% bazelVersion %}}
and installation instructions can be found [here](http://bazel.io/docs/install.html).

To ensure that Bazel has been installed, run `bazel version` and check the
version (listed next to `Build label` in the script's output) to ensure that you
have Bazel {{% bazelVersion %}}.

## Configuring Bazel

There is a Python script that you can run to configure Bazel on supported
platforms:

```bash
$ cd /path/to/heron
$ ./bazel_configure.py
```

## Building

### Bazel OS Environments

Bazel builds are specific to a given OS. When building you must specify an
OS-specific configuration using the `--config` flag. The following OS values
are supported:

* `darwin` (Mac OS X)
* `ubuntu` (Ubuntu 18.04)
* `debian` (Debian10)
* `centos5` (CentOS 7)

For example, on Mac OS X (`darwin`), the following command will build all
packages:

```bash
$ bazel build --config=darwin heron/...
```

Production release packages include additional performance optimizations
not enabled by default. Enabling these optimizations increases build time.
To enable production optimizations, include the `opt` flag:
```bash
$ bazel build -c opt --config=PLATFORM heron/...
```

### Building All Components

The Bazel build process can produce either executable install scripts or
bundled tars. To build executables or tars for all Heron components at once,
use the following `bazel build` commands, respectively:

```bash
$ bazel build --config=PLATFORM scripts/packages:binpkgs
$ bazel build --config=PLATFORM scripts/packages:tarpkgs
```

Resulting artifacts can be found in subdirectories below the `bazel-bin`
directory. The `heron-tracker` executable, for example, can be found at
`bazel-bin/heron/tools/tracker/src/python/heron-tracker`.

### Building Specific Components

As an alternative to building a full release, you can build Heron executables
for a single Heron component (such as the [Heron
Tracker](user-manuals-heron-tracker-runbook)) by passing a target to the `bazel
build` command. For example, the following command would build the Heron Tracker:

```bash
$ bazel build --config=darwin heron/tools/tracker/src/python:heron-tracker
```

## Testing Heron

Instructions for running Heron unit tests can be found at [Testing
Heron](compiling-running-tests).