4 ms·

It works great if you don't use modules internally. Either go with plain GOPATH, or use something like Bazel/rules_go/Gazelle. Modules are not for monorepos an

by q3k 5y ago

It works great if you don't use modules internally. Either go with plain GOPATH, or use something like Bazel/rules_go/Gazelle. Modules are not for monorepos and internal components, modules are for third party dependencies that need to be pulled in at compatible versions, and for general multirepo work.

tsimionescu 5y ago
"third-party" dependencies can easily exist between teams in the same company sharing the same mono-repo. It's perhaps not as common with git, but other version control systems are much more often used as monorepos, often for building multiple unrelated projects, with some common tooling libraries used as modules. This is trivial to do with any other module system I've used (Maven, Nuget, Konan, pip, cargo), but it is extraordinarily brittle with Go.
- q3k 5y ago
  > "third-party" dependencies can easily exist between teams in the same company sharing the same mono-repo. [...] This is trivial to do with any other module system I've used (Maven, Nuget, Konan, pip, cargo), but it is extraordinarily brittle with Go. I don't understand? This should literally just be an import statement. If your Git repository is anchored at importpath "source.example.com/git", and your code lives under "app/service/backend", and wants to import "lib/db/mysql", it just does so via `import "source.example.com/git/lib/db/mysql"`. No need to use Go modules at all. Or if you do need to use Go modules, just have one module for the entire repository. The only reason I can see this not work is if you have multiple Go modules in a single repository, or even worse have module import paths not corresponding to paths within the monorepo. But in that case the fix is easy: just don't do that?
  - tsimionescu 5y ago
    What if I want to use version 1.4.1 in one project, but 1.0.3 in another project? Modules serve a purpose inside a (large) organization just as between organizations, and tying modules to your source control choices is a generally bad idea.
    - q3k 5y ago
      > What if I want to use version 1.4.1 in one project, but 1.0.3 in another project? One of the main reasons to use a monorepo is to work at a single HEAD, letting you do large scale refactors within single/linked commits, without ever having to fork any code due to breakage (as you change both sides of a potentially breaking contract in the same change). I would argue that if you're attempting to do multiple code versions in a monorepo, you're doing monorepos wrong. Or at least, you're not doing them Google-style, and that's really what GOPATH and Go has been engineered to work well with. In that case, yes, you will likely hit an impedance mismatch with Go OOTB. But I'm also quite sure it's possible to write custom tooling around the Go compiler to work with this setup (ie. use `go tool compile` and set things up manually for compilation, without using `go build` which is quite opinionated). However, if you have a monorepo with multiple code versions per subpath, what you're really doing is multirepo disguised as a technically-a-monorepo-I-guess-I-mean-it's-a-single-repo-that-makes-it-a-monorepo, with none of the benefits of either approach.
      - tsimionescu 5y ago
        Having a monorepo is the default, especially for centralized VCS. You start with one repo, and never stop adding to it. Different projects live in different directories of the monorepo, and they each maintain their own branches etc. This ensures you have a common place to look for code, and more importantly, it ensures you have a unique history for all of your code - what often happens is that ProjectA has some internal library LibA; after a while, ProjectB needs functionality similar to LibA, so now you move LibA from /ProjectA to /Libs/LibA, and can easily re-use it across ProjectA and ProjectB. But in older branches of ProjectA (e.g. a hotfix branch for an already released version) it is still a sub-folder, and you can keep moving bug fixes from here to there. If you split all of this into different repos, you can't really carry over history, at least not with ease, and definitely not while both versions live together. However, code artifacts should be versioned separately from all of this - you create builds all the time, and they, by default, use fixed versions of both external and internal libraries, as there is no reason to spend time updating a library that already does all you need - especially not while it is work-in-progress. So you have a build system that creates and consumes artifacts, and that tracks dependencies between artifacts.

by q3k 5y ago

tsimionescu 5y ago

"third-party" dependencies can easily exist between teams in the same company sharing the same mono-repo. It's perhaps not as common with git, but other version control systems are much more often used as monorepos, often for building multiple unrelated projects, with some common tooling libraries used as modules. This is trivial to do with any other module system I've used (Maven, Nuget, Konan, pip, cargo), but it is extraordinarily brittle with Go.

q3k 5y ago
> "third-party" dependencies can easily exist between teams in the same company sharing the same mono-repo. [...] This is trivial to do with any other module system I've used (Maven, Nuget, Konan, pip, cargo), but it is extraordinarily brittle with Go. I don't understand? This should literally just be an import statement. If your Git repository is anchored at importpath "source.example.com/git", and your code lives under "app/service/backend", and wants to import "lib/db/mysql", it just does so via `import "source.example.com/git/lib/db/mysql"`. No need to use Go modules at all. Or if you do need to use Go modules, just have one module for the entire repository. The only reason I can see this not work is if you have multiple Go modules in a single repository, or even worse have module import paths not corresponding to paths within the monorepo. But in that case the fix is easy: just don't do that?
- tsimionescu 5y ago
  What if I want to use version 1.4.1 in one project, but 1.0.3 in another project? Modules serve a purpose inside a (large) organization just as between organizations, and tying modules to your source control choices is a generally bad idea.
  - q3k 5y ago
    > What if I want to use version 1.4.1 in one project, but 1.0.3 in another project? One of the main reasons to use a monorepo is to work at a single HEAD, letting you do large scale refactors within single/linked commits, without ever having to fork any code due to breakage (as you change both sides of a potentially breaking contract in the same change). I would argue that if you're attempting to do multiple code versions in a monorepo, you're doing monorepos wrong. Or at least, you're not doing them Google-style, and that's really what GOPATH and Go has been engineered to work well with. In that case, yes, you will likely hit an impedance mismatch with Go OOTB. But I'm also quite sure it's possible to write custom tooling around the Go compiler to work with this setup (ie. use `go tool compile` and set things up manually for compilation, without using `go build` which is quite opinionated). However, if you have a monorepo with multiple code versions per subpath, what you're really doing is multirepo disguised as a technically-a-monorepo-I-guess-I-mean-it's-a-single-repo-that-makes-it-a-monorepo, with none of the benefits of either approach.
    - tsimionescu 5y ago
      Having a monorepo is the default, especially for centralized VCS. You start with one repo, and never stop adding to it. Different projects live in different directories of the monorepo, and they each maintain their own branches etc. This ensures you have a common place to look for code, and more importantly, it ensures you have a unique history for all of your code - what often happens is that ProjectA has some internal library LibA; after a while, ProjectB needs functionality similar to LibA, so now you move LibA from /ProjectA to /Libs/LibA, and can easily re-use it across ProjectA and ProjectB. But in older branches of ProjectA (e.g. a hotfix branch for an already released version) it is still a sub-folder, and you can keep moving bug fixes from here to there. If you split all of this into different repos, you can't really carry over history, at least not with ease, and definitely not while both versions live together. However, code artifacts should be versioned separately from all of this - you create builds all the time, and they, by default, use fixed versions of both external and internal libraries, as there is no reason to spend time updating a library that already does all you need - especially not while it is work-in-progress. So you have a build system that creates and consumes artifacts, and that tracks dependencies between artifacts.