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.
- It will be nearly impossible to find anything using GitHub Search,
-
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 [<dependency>...]- install git submodules for specified/all dependencies;-U [<dependency>...]- update specified/all already vendored dependencies;-R [<dependency>...]- remove git submodules for specified/all dependencies;-Q [<dependency>...]- 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.