Codecs for event triggers, including webhook transforms. These are not hooked into the higher-up table metadata codec yet because some backend implementations implement event triggers with `error` which causes an error when codecs are evaluated. I plan to follow up with another PR to resolve that.
Ticket: https://hasurahq.atlassian.net/browse/GDC-585
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7237
GitOrigin-RevId: 8ce40fe6fedcf8b109d6ca50a505333df855a8ce
## Description ✍️
This PR adds support to generate query params directly using a kriti template which can be used to flatten a list of parameter arguments as well.
### Changes in the Metadata API
Earlier the `query_params` key inside `request_transform` used to take in an object of key/value pairs where the `key` represents the query parameter name and `value` points to the value of the parameter or a kriti template which could be resolved to the value.
With this PR, we provide the user with more freedom to generate the complete query string using kriti template. The `query_params` can now take in a string as well which will be a kriti template. This new change needs to be incorporated on the console and CLI metadata import/export as well.
- [x] CLI: Compatible, no changes required
- [ ] Console
## Changelog ✍️
__Component__ : server
__Type__: feature
__Product__: community-edition
### Short Changelog
use kriti template to generate query param from list of arguments
### Related Issues ✍
https://hasurahq.atlassian.net/browse/GS-243
### Solution and Design ✍
We use a kriti template to generate the complete query parameter string.
| Query Template | Output |
|---|---|
| `{{ concat ([concat({{ range _, x := [\"apple\", \"banana\"] }} \"tags={{x}}&\" {{ end }}), \"flag=smthng\"]) }}`| `tags=apple&tags=banana&flag=smthng` |
| `{{ concat ([\"tags=\", concat({{ range _, x := $body.input }} \"{{x}},\" {{ end }})]) }}` | `tags=apple%2Cbanana%2C` |
### Steps to test and verify ✍
- start HGE and make the following request to `http://localhost:8080/v1/metadata`:
```json
{
"type": "test_webhook_transform",
"args": {
"webhook_url": "http://localhost:3000",
"body": {
"action": {
"name": "actionName"
},
"input": ["apple", "banana"]
},
"request_transform": {
"version": 2,
"url": "{{$base_url}}",
"query_params": "{{ concat ([concat({{ range _, x := $body.input }} \"tags={{x}}&\" {{ end }}), \"flag=smthng\"]) }}",
"template_engine": "Kriti"
}
}
}
```
- you should receive the following as output:
```json
{
"body": {
"action": {
"name": "actionName"
},
"input": [
"apple",
"banana"
]
},
"headers": [],
"method": "GET",
"webhook_url": "http://localhost:3000?tags=apple&tags=banana&flag=smthng"
}
```
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6961
Co-authored-by: Tirumarai Selvan <8663570+tirumaraiselvan@users.noreply.github.com>
GitOrigin-RevId: 712ba038f03009edc3e8eb0435e723304943399a
What is the `Cacheable` type class about?
```haskell
class Eq a => Cacheable a where
unchanged :: Accesses -> a -> a -> Bool
default unchanged :: (Generic a, GCacheable (Rep a)) => Accesses -> a -> a -> Bool
unchanged accesses a b = gunchanged (from a) (from b) accesses
```
Its only method is an alternative to `(==)`. The added value of `unchanged` (and the additional `Accesses` argument) arises _only_ for one type, namely `Dependency`. Indeed, the `Cacheable (Dependency a)` instance is non-trivial, whereas every other `Cacheable` instance is completely boilerplate (and indeed either generated from `Generic`, or simply `unchanged _ = (==)`). The `Cacheable (Dependency a)` instance is the only one where the `Accesses` argument is not just passed onwards.
The only callsite of the `unchanged` method is in the `ArrowCache (Rule m)` method. That is to say that the `Cacheable` type class is used to decide when we can re-use parts of the schema cache between Metadata operations.
So what is the `Cacheable (Dependency a)` instance about? Normally, the output of a `Rule m a b` is re-used when the new input (of type `a`) is equal to the old one. But sometimes, that's too coarse: it might be that a certain `Rule m a b` only depends on a small part of its input of type `a`. A `Dependency` allows us to spell out what parts of `a` are being depended on, and these parts are recorded as values of types `Access a` in the state `Accesses`.
If the input `a` changes, but not in a way that touches the recorded `Accesses`, then the output `b` of that rule can be re-used without recomputing.
So now you understand _why_ we're passing `Accesses` to the `unchanged` method: `unchanged` is an equality check in disguise that just needs some additional context.
But we don't need to pass `Accesses` as a function argument. We can use the `reflection` package to pass it as type-level context. So the core of this PR is that we change the instance declaration from
```haskell
instance (Cacheable a) => Cacheable (Dependency a) where
```
to
```haskell
instance (Given Accesses, Eq a) => Eq (Dependency a) where
```
and use `(==)` instead of `unchanged`.
If you haven't seen `reflection` before: it's like a `MonadReader`, but it doesn't require a `Monad`.
In order to pass the current `Accesses` value, instead of simply passing the `Accesses` as a function argument, we need to instantiate the `Given Accesses` context. We use the `give` method from the `reflection` package for that.
```haskell
give :: forall r. Accesses -> (Given Accesses => r) -> r
unchanged :: (Given Accesses => Eq a) => Accesses -> a -> a -> Bool
unchanged accesses a b = give accesses (a == b)
```
With these three components in place, we can delete the `Cacheable` type class entirely.
The remainder of this PR is just to remove the `Cacheable` type class and its instances.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6877
GitOrigin-RevId: 7125f5e11d856e7672ab810a23d5bf5ad176e77f
## Description
Some of the documentation/organizational changes I was putting into the suggestions for #3624 were a bit too convoluted for GitHub's suggestion interface, so I'm putting them here instead.
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/3910
Co-authored-by: Solomon <24038+solomon-b@users.noreply.github.com>
GitOrigin-RevId: 06e0cb08bd18e7f8b21452df0697cfd80bc56fde
