MANUL 
Manul is a vendoring utility for Go programs.
Installation
manul can be obtained using go get:
go get github.com/kovetskiy/manul
Packages are also available for Ubuntu/Debian and Arch Linux.
What's the reason for yet another utility?
Because all other vendor utilities suffer from the following:
-
Some wrap the
gobinary and spoof theGOPATHenv variable. You will have a non-go-gettable project which needs additional software in order to compile and run; -
Some copy the source code of dependencies into the vendor directory:
- It will be nearly impossible to find anything using GitHub Search, because you will get many false-positive results;
- Updating dependencies will require manual intervention and committing a lot of modified lines straight into the main repo;
- You will not be able to tell what version of dependency your project is using will by looking at repository; you have to keep versions in the additional ambiguous file with vendors associated with commits.
-
Various architecture problems:
- Impossible to update all or specific vendored dependencies;
- Impossible to rollback vendored dependencies to specific version;
- Impossible to remove unused vendored dependencies;
- Impossible to lock version of vendored dependency.
Solution
We all love git, it's a very powerful instrument. Why don't we use its power for vendoring dependencies using an awesome feature, which is called git submodule?
With git submodule you will have a git repository for each dependency. They can be managed in the same way as main project by git.
Pros:
-
No need for additional software for building/running your Go project;
-
No need for additional JSON/TOML/YAML file for storing dependencies;
-
Update vendored dependencies directly from remote origins;
-
Rollback changes in dependencies;
-
Go-gettable
git submodule might look like a Silver Bullet, but it's still clumsy to work with manually. We want to have a powerful yet simple interface for vendoring dependencies using this technology.
manul can do it for us.
Usage
Who needs a documentation when there are GIFs?
First of all, we should request dependencies which we have in our project. To do this, just run manul with -Q (query) flag. It will output all the project imports (dependencies), like this:
For example, we have six dependencies, let's lock versions of critical dependencies by adding submodules: in our case it's zhash and blackfriday packages.
For locking versions (installing dependencies) we should use -I (install) flag and specify dependencies, which we wish to install:
After installation we can have a look for vendored and non-vendored dependencies by using flag -Q. After previous step we should see git commits along with two already vendored dependencies (zhash and blackfriday):
Let's install submodules for remaining dependencies, go the limit! Just run manul with flag -I without specifying any dependencies, manul will install all detected dependencies with skipping already vendored:
Wow, that was crazy! Now, to update some vendored dependencies, for example, docopt-go package, manul should be invoked with the flag -U and import path (github.com/docopt/docopt-go):
manul can be used to remove specified submodules of vendored dependencies by using -R (remove) flag and specifying dependencies import path:
By the way, manul can detect and remove unused vendored dependencies using -C (clean) flag:
manul can also get you a specific version of a dependency by using a commit-ish, for example:
manul -I golang.org/x/foo=34a235h1will installfooat the specified commitmanul -U github.com/x/bar=this-tagwill update it tothis-tagversion.
Let's summarize:
-I [- install git submodules for specified/all dependencies;...] -U [- update specified/all already vendored dependencies;...] -R [- remove git submodules for specified/all dependencies;...] -Q [- list all used dependencies;...] -C- detect and remove all git submodules for unused vendored dependencies.
You can see similar help message by passing -h or --help flag.
