How to add local dependency to vendor when using go mod

Question

Before I used go dep, but now office ensure the official tool is go mod.

When I use go dep, I can add local dependency packages to vendor and ignored in Gopkg.toml to ignore search the package from repo. I can execute go dep update normally.

Now I use go mod, I also add local dependence package to vendor and add it exclude in go.mod. But when i execute go mod tidy, it remove the package even though my project exist import xxx.

What did i do:

1. create new project
2. execute go mod init

3. modify go.mod exclude privaterepo.com/bb/bb

4. copy my local module to vendor because the local module is on a private repo which not support https.

5. now the vendor just like:

   vendor |-github.com/aa/aa |-privaterepo.com/bb/bb

6. import "privaterepo.com/bb/bb"
7. execute go build -mod vendor
8. than i got error "cannot find module for path privaterepo.com/bb/bb" 9 always try with replace, but it also not work

So, what should I do to add local package to vendor and avoid go mod remove it?

Answer 1

So, what should I do to add local package to vendor and avoid go mod remove it?

Well, I think you cannot do this. This is not how it works. go mod vendor manages your vendor folder.

Instead of excludeing you package from go.mod you should add a replace directive to instruct the go tool to look up the package not from privaterepo.com but from the local filesystem. Quoting from https://github.com/golang/go/wiki/Modules#when-should-i-use-the-replace-directive

replace also can be used to inform the go tooling of the relative or absolute on-disk location of modules in a multi-module project, such as:

   replace example.com/project/foo => ../foo

So in your case: Do not try to manually put privaterepo.com/bb/bb in vendor, but have it somewhere outside the current project and use

replace privaterepo.com/bb/bb => ../bb

And let go mod copy this stuff from the filesystem to your vendor.