https://github.com/pdcalado/gotype2cli
Generate a cli from Go types
https://github.com/pdcalado/gotype2cli
cli code-generation generator go
Last synced: about 2 months ago
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Generate a cli from Go types
- Host: GitHub
- URL: https://github.com/pdcalado/gotype2cli
- Owner: pdcalado
- License: mit
- Created: 2023-03-01T18:14:17.000Z (about 2 years ago)
- Default Branch: main
- Last Pushed: 2024-10-13T12:07:07.000Z (7 months ago)
- Last Synced: 2025-01-21T17:31:11.958Z (3 months ago)
- Topics: cli, code-generation, generator, go
- Language: Go
- Homepage:
- Size: 78.1 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# gotype2cli
Generate code to create a cli command from your Go types.
## What!?
Let's say you've got a type like this:
```go
type Bar struct {
Height int `json:"height"`
}
// New creates a new bar
func New(height int) Bar {
return Bar{
Height: height,
}
}
// String returns a string representation of the bar
func (b *Bar) String() string {
return fmt.Sprintf("the bar is %d meters high", +b.Height)
}
// Raise raises the bar by 1
func (b *Bar) Raise() {
b.Height += 1
}
// RaiseBy raises the bar by the given amount
func (b *Bar) RaiseBy(amount int) {
b.Height += amount
}
// RaiseFromBars raises the bar by the sum of the heights of the given bars
func (b *Bar) RaiseFromBars(bars ...Bar) {
for _, bar := range bars {
b.Height += bar.Height
}
}
```
Using `gotype2cli` you can generate a cli command that creates and manipulates `Bar` by calling its methods, allowing you to do stuff like:
```console
foo@bar:~$ bar new 10
{"height":10}
foo@bar:~$ # methods with Bar as receiver, read a bar in JSON from stdin
foo@bar:~$ bar new 10 | bar raise
{"height":11}
foo@bar:~$ # methods with Bar as receiver can get a Bar in json as first argument
foo@bar:~$ bar new 10 | bar raise-by 2
{"height":12}
foo@bar:~$ bar new 10 | bar raise | bar raise
{"height":12}
foo@bar:~$ bar new 11 | bar string
"the bar is 11 meters high"
foo@bar:~$ # variadic methods are supported using json arrays
foo@bar:~$ bar new 10 | bar raise-from-bars '[{"height": 2},{"height": 3},{"height": 4}]'
{"height":19}
foo@bar:~$ # exported fields can be set (not implemented)
foo@bar:~$ bar new 10 | bar height 11
{"height":11}
foo@bar:~$ # exported fields can be read (not implemented)
foo@bar:~$ bar new 10 | bar height
{"height":10}
foo@bar:~$ # a patch flag is available to print a JSON patch instead of the object
foo@bar:~$ # (not implemented)
foo@bar:~$ bar new 10 | bar height 11 --patch
[{"op":"replace","path":"/height","value":11}]
foo@bar:~$ # usage and help are generated from code and comments
foo@bar:~$ bar raise-by --help
Usage: bar raise-by [options]
RaiseBy raises the bar by the given amount.
Returns a modified Bar in json format.
If --patch is set, returns a JSON patch instead.
Bar is read from stdin in JSON format.
```
(function names are converted to kebab-case for a more cli-like experience)
(`--no-object` and `--patch` are not implemented yet, check [TODO](#todo) for more info)
## Gotchas
- generated code depends on [cobra](https://github.com/spf13/cobra)
- methods with Bar as receiver assume first argument is a Bar
- methods returning an error are turned into commands that behave as follows:
- if error is nil, print Bar in JSON
- if error is not nil, print error message and exit with status 1
- if flag `--no-object` is set, print error value (nil or message)
- the flag `--no-object` can be used to disable the default behavior of printing the object
- all types involved must be JSON compatible, including function arguments
## TODO
- [ ] add support for the `--no-object` flag mentioned above.
- [ ] add support for the `--patch` flag mentioned above.