They are quite different, speaking of Bazel it’s designed to be an all inclusive build system for any language at essentially infinite scale. Which means it:
- Built in distributed execution support (for any build step)
- All work scales by part of tree you are building not it’s absolute size
- Support for fetching external source code and binary deps
- Has first class support for executing and testing containers
- Has first class support for code gen (ie you can build a compiler use it to generate code, then build its output,and everything works, no hacks in one build system)
The downsides:
- Works best if you all your code is built with Bazel, which makes deps hard
- Support for Python is weak, Ruby non existent, and Node is beta quality
- Has essentially zero convention, everything must be explicitly configured (ie explicitly describing go deps)
- Has a memory hungry local java daemon
- Has a more overhead than ninja (but is more accurate because of hashing and isolation)
One downside I found: it makes heavy use of symlinking which doesn't always play well with other tools (in particular: Go tools) and I found made things particularly annoying when I used Bazel from inside docker and outside docker (the symlinks left don't match what's on my host).
I've had to fight through Bazel somewhat when working with Tensorflow.
My impression was that it probably suits Google's internal needs very well, but it's really complicated compared to CMake. I'm not sure that for most developers the learning curve would be worthwhile.
- Has nice Python based DSL
- Strongly encourages 100% explicit dependency specification
- Has built in caching (local and remote)
- Built in test result caching
- a fully featured build graph query language
- Built in distributed execution support (for any build step)
- All work scales by part of tree you are building not it’s absolute size
- Support for fetching external source code and binary deps
- Has first class support for executing and testing containers
- Has first class support for code gen (ie you can build a compiler use it to generate code, then build its output,and everything works, no hacks in one build system)
The downsides:
- Works best if you all your code is built with Bazel, which makes deps hard
- Support for Python is weak, Ruby non existent, and Node is beta quality
- Has essentially zero convention, everything must be explicitly configured (ie explicitly describing go deps)
- Has a memory hungry local java daemon
- Has a more overhead than ninja (but is more accurate because of hashing and isolation)