As presented in Chapter 1, Meeting the Yocto Project, BitBake is a task scheduler (like GNU Make) that parses shell and Python scripts. The code parsed generates and runs tasks (configure, compile, and so on), which are basically sets of steps ordered according to the code's dependencies.
Here are some points taken directly from the BitBake user manual:
BitBake executes tasks according to the provided metadata, which builds up the tasks. Metadata is stored in recipe (
.bb), configuration (.conf), and class (.bbclass) files and provides BitBake with instructions on what tasks to run and the dependencies between those tasks.BitBake includes a fetcher library for obtaining source code from various places, such as source control systems or websites.
The instructions for each unit to be built (such as a piece of software) are known as recipe files and contain all the information about the unit (dependencies, source file locations, checksums, description, and so on).
BitBake includes a client...