4 ms·

Isn’t Bazel based off another tool they use internally?

Spinfusor 7y ago
Yes: the internal tool is Blaze
klodolph 7y ago
Yes. My guess is that over a long enough period of time, the internal build system will migrate to Bazel. But I don’t think it will happen soon. Large migrations are always a pain, but Bazel does make it easier (since you can isolate dependencies very well and migrate bottom-up). I don’t work there, but I have talked to Googlers working on build systems.
- ses1984 7y ago
  I want to try this with a monorepo codebase now but every time I try to get started I feel overwhelmed. I'm trying to sell my team on it, but none of us has experience with bazel. I'm trying to figure out how to do a small poc where we migrate one intermediate thing in the monorepo to bazel and try to prove out how it can take over everything.
  - klodolph 7y ago
    I have personally done this. - You are going to screw things up a couple times. The documentation for Bazel is not always clear, but you can usually find examples or explanations of complicated stuff on forums somewhere. - Start with a leaf dependency, something in your codebase that doesn’t depend on anything else. Then work your way up. Just write a WORKSPACE + BUILD.bazel in your root, and then put a BUILD.bazel in the directory for the dependency you are going to work on. - Look at examples like Tensor Flow, especially for how to handle third-party dependencies (although Tensor Flow is going to do it in a more complicated way). - Migrate your tests as you go. - Just run "bazel build //...:all" or "bazel test //...:all" from your project root as you go to make sure things don’t break. - Undoubtedly it will take a while to develop a good mental model of how Bazel works. For fun, try looking around in the output directories, or look at the sandboxes it creates.
    - ses1984 7y ago
      I appreciate your help and was curious if you could field one more specific question: What if I wanted to fork tensorflow and integrate my project into it, would I need the tensorflow fork as something like a git submodule in my main repo, or is there a way to tell bazel there's another repo somewhere else and where it fits into the graph?
- evmar 7y ago
  Bazel is just the open source name of the internal Google build system, it is the same codebase.
  - klodolph 7y ago
    From what I understand, the two tools have some very significant differences at this point. They may be the same codebase in a broad sense, and may share a lot of code, but I bet they are using something like Copybara to synchronize them. https://github.com/google/copybara https://github.com/google/copybara

Yes: the internal tool is Blaze

Yes. My guess is that over a long enough period of time, the internal build system will migrate to Bazel. But I don’t think it will happen soon. Large migrations are always a pain, but Bazel does make it easier (since you can isolate dependencies very well and migrate bottom-up). I don’t work there, but I have talked to Googlers working on build systems.

ses1984 7y ago
I want to try this with a monorepo codebase now but every time I try to get started I feel overwhelmed. I'm trying to sell my team on it, but none of us has experience with bazel. I'm trying to figure out how to do a small poc where we migrate one intermediate thing in the monorepo to bazel and try to prove out how it can take over everything.
- klodolph 7y ago
  I have personally done this. - You are going to screw things up a couple times. The documentation for Bazel is not always clear, but you can usually find examples or explanations of complicated stuff on forums somewhere. - Start with a leaf dependency, something in your codebase that doesn’t depend on anything else. Then work your way up. Just write a WORKSPACE + BUILD.bazel in your root, and then put a BUILD.bazel in the directory for the dependency you are going to work on. - Look at examples like Tensor Flow, especially for how to handle third-party dependencies (although Tensor Flow is going to do it in a more complicated way). - Migrate your tests as you go. - Just run "bazel build //...:all" or "bazel test //...:all" from your project root as you go to make sure things don’t break. - Undoubtedly it will take a while to develop a good mental model of how Bazel works. For fun, try looking around in the output directories, or look at the sandboxes it creates.
  - ses1984 7y ago
    I appreciate your help and was curious if you could field one more specific question: What if I wanted to fork tensorflow and integrate my project into it, would I need the tensorflow fork as something like a git submodule in my main repo, or is there a way to tell bazel there's another repo somewhere else and where it fits into the graph?
evmar 7y ago
Bazel is just the open source name of the internal Google build system, it is the same codebase.
- klodolph 7y ago
  From what I understand, the two tools have some very significant differences at this point. They may be the same codebase in a broad sense, and may share a lot of code, but I bet they are using something like Copybara to synchronize them. https://github.com/google/copybara https://github.com/google/copybara