add `dispatch init` command

chicoxyzzy commented 2 months ago

This PR implements dispatch init command to initialize a new project.

Usage

dispatch init <template> [path]

Where <template> is a required option and [path] is optional.

Templates directory

On a first use the command will create an Application Data directory dispatch

Windows: The application data directory is typically located at %APPDATA% or %LOCALAPPDATA%.
macOS: The application data directory is typically located at $HOME/Library/Application Support.
Linux: The application data directory is typically located at $XDG_CONFIG_HOME or $HOME/.config.

The App Data directory is used to save templates oh a user's computer to make them available for use later without Internet. The directory has follows structure:

dispatch/
  templates/
    foo/
    bar/
  templates.sha

Workflow

1) dispatch init <template> will try to get the SHA of the latest commit from the repository and compare it to local SHA. If values differ, Dispatch CLI will download update for templates first. 2) Dispatch CLI makes request to using GitHub REST API to download tarball of the latest commit and then extracts it into the Dispatch's App Data directory. 3) Finally, it copes template's files from the App Data directory (provided as <template> option) to a current working directory or to the [path] if it was provided.

If the destination directory is not empty, user will be asked if they want to clear the directory

Try it

git checkout init_command
make build
./build/darwin/arm64/dispatch init cat-facts ~/dispatch-template-test

This will create cat-facts template in the dispatch-template-test of your home directory. Note that build directory can be different for your computer's arch and OS

To clear templates cache

rm -rf ~/Library/Application\ Support/dispatch

if you use MacOS

Notes and open questions

Current PR uses https://github.com/dispatchrun/dispatch-examples as a templates repo for the demonstration purpose only. We should introduce a new repo for templates.
Should we introduce versioning for templates to make them compatible with different versions of SDKs? I think we should
We can improve the templates update by adding information about which templates have been added/removed/modified or/and show last N commit messages and link to the full diff on GitHub between two SHAs
Current implementation makes it pretty easy to add 3rd-party templates (as described in #59), but
- it is easy to just use git clone instead (although init's caching and templates updating features could be still useful)
- we should signal user that it is a 3rd-party template and it's not maintained by dispatch.run
~~Should dispatch init go to the Dispatch Commands group or should it be in the Additional Commands in the dispatch -h output?~~ it's in the Dispatch group

Closes #59

chicoxyzzy commented 2 months ago

This also still needs tests and docs update, but I wanted to start discussion earlier.

chicoxyzzy commented 2 months ago

Ok, I think it's ready. I've also created a templates repo, please review it: https://github.com/dispatchrun/dispatch-templates

vadimdemedes commented 2 months ago

"dispatch init

dispatchrun / dispatch