# glv8
Ever wanted to write functional type-safe postgresql procedures ? Let's use [gleam](https://gleam.run) !
[](https://hex.pm/packages/glv8)
[](https://hexdocs.pm/glv8/)
glv8 coworks with [plv8](https://plv8.github.io). It provides plv8's API bindings so one can
write procedures with gleam and let `plv8` do the needed proxying. Specifically, gleam codes are
compiled as JavaScript and interoperate with plv8 ecosystem. For example
```gleam
pub fn catch_sql_error() -> Nil {
let r = database.execute("throw SQL error", Nil)
use <- bool.guard(result.is_ok(r), Nil)
case r {
Error(glv8.DBErrorJson(j)) -> elog_notice(j |> json.to_string)
_ -> elog_notice("should not come here")
}
}
```
The snippet can be provisioned with `plv8` declaration
```sql
CREATE FUNCTION catch_sql_error() RETURNS void AS
$$
glv8.catch_sql_error();
$$ LANGUAGE plv8;
```
More examples can be found at `src/app/plv8.gleam`
Further documentation can be found at <https://hexdocs.pm/glv8>.
## Development
- write any gleam functions, with `pub fn` specifier in any packages.
- provide needed proxying sqls
- declare them in the `exports` and `sqls` of `bundle.gleam`
- build (or watch build) them with npm scripts
- the artifacts are `dist/glv8_init.sql` which wraps up all the exported gleam functions
and the needed proxying sqls
- by default, the gleam functions use prefix `glv8.` as namespace, one can overwrite
it with envionment variable `GLV8_NAMESPACE`
```sh
$ npm run build
$ npm run watch
$ npm run clean
$ npm run purge
```
## Deployment
- postgresql database with `plv8` trusted language extension.
- glv8 needs `SET plv8.start_proc = 'glv8_init';` either in `postgresql.conf` or session pre-request
- deploy artifacts `glv8_init.sql` and all the other proxying sqls
- enjoy
## RoadMap
- auto-generate proxying sqls as [plv8ify](https://github.com/divyenduz/plv8ify) with `glance` (it might be rigid and over-kill after all)
