Bazel Build for C++ Software Application

Bazel Tool is developed by google to automate the build process. Now It's an open source and it can be used by anyone. Many companies are using it for their day-to-day build automation. It is very helpful to integrate with CI/CD pipeline. GoogleTest framework can be integrated easily for the Unit Testing of an application.

Features of Bazel

• Speedup Build and Test: It has very good features for rebuilding the application in an optimized way with local and distributed cache techniques. Optimized dependency analysis and concurrent execution of builds. This feature boosts regular builds and provides the build results in well defined time.
• Multiple Language and Multi-Platform Support: It can build Java, Go, C++, and many more languages on different platforms like Windows, Linux, and Mac
• Scalable: Bazel helps you scale your organization, codebase, and continuous integration solution. It handles codebases of any size, in multiple repositories or a huge mono repo.

Advantages from bazel in the modern build process

1. The build completely depends on the input which is provided. Your input can decide which part of the code needs to rebuild and produce constant output.?

2. Easy to integrate with Docker and Kubernetes. If you have mono repo and multiple microservices, then It can build each container and host it for the test environment. Further, it can provide incremental build and perform deployment by using any orchestration tools like AWS and Kubernetes.

3. Bazel can handle large projects. Bazel provides a uniform interface for building and testing across projects and programming languages, which is beneficial to CI/CD Process.

4. Bazel used an internal caching mechanism. It caches the builds and rebuilds the content only when the developer made the changes. It compares the previous build which is cached and newly built content and produces the final binary. This caching technique speed up the build process.

Bazel Build Structure:

• workspace:

1. A workspace is a directory tree on your filesystem that contains the source files for the software you want to build. Each workspace has a text file named WORKSPACE which may be empty or may contain references to external dependencies required to build the outputs.
2. Directories containing a file called WORKSPACE are considered the root of a workspace. Therefore, Bazel ignores any directory trees in a workspace rooted at a subdirectory containing a WORKSPACE file, as they form another workspace.
3. Bazel also supports the WORKSPACE.bazel file as an alias of the WORKSPACE file. If both files exist, WORKSPACE.bazel is used.

• Package:

1. The primary unit of code organization in a repository is the package. A package is a collection of related files and a specification of how they can be used to produce output artifacts.
2. This folder will contain the BUILD and BUILD.bazel files. It holds all other folders required for the build.

• Target:

1. A package is a container of targets, which are defined in the package's BUILD file. Most targets are one of two principal kinds, files and rules.
2. Files are further divided into two kinds. Source files are usually written by the efforts of people, and checked into the repository. Generated files, sometimes called derived files or output files, are not checked in, but are generated from source files.?

Labels:

All targets belong to exactly one package. The name of a target is called its label. Every label uniquely identifies a target. A typical label in canonical form looks like this:

@myrepo//my/app/main:app_binary        

Dependencies:

A target A depends upon a target B if B is needed by A at build or execution time. The depends upon relation induces a Directed Acyclic Graph (DAG) over targets, and it is called a dependency graph.

code and compilation process will be updated soon.