[gateway-api] bad behavior on TransformationException if no policyChain

[ytvnr]

:collision: Describe the bug

We have weird behaviour resulting in timeout when a TransformationException occurs in a TransformableRequestStream or TransformableResponseStream and no policyChain is set.

With the fix, the API will end will a readable error instead of timeout.

:sunrise_over_mountains: To Reproduce

You can check with this API: https://apim-3-10-x-console.cloud.gravitee.io/#!/environments/DEFAULT/apis/69635ef0-422e-4259-a35e-f0422ef25959/design

Flows are already configured to have the error

JsonToJson Policy

Steps to reproduce the behaviour:

1. Go to Design studio
2. Add JsonToJson with a bad JOLT specification
3. Try your api postman
4. It ends in a timeout error (postman)

JsonToXml Policy

Steps to reproduce the behaviour:

1. Go to Design studio
2. Add JsonToXml twice in a row to reproduce the error
3. Try your api postman
4. It ends in a timeout error (postman)

JWS Policy

Not reproduced

XmlToJson Policy

Steps to reproduce the behaviour:

1. Go to Design studio
2. Add XmlToJson with a bad input generated by Assign content policy
3. Try your api postman
4. It ends in a timeout error (postman)

XSLT Policy

Steps to reproduce the behaviour:

1. Go to Design studio
2. Add Xslt policy with a bad timesheet
3. Try your api postman
4. It ends in a timeout error (postman)

:rainbow: Expected behaviour

The chain should fail properly. (no timeout)

:movie_camera: Useful information

• [x] JsonToJson Policy and XsltPolicy are good examples but we need to investigate if other policies are in this case.
• [x] We should fix this policies to build the TransformableStream with a PolicyChain
• [x] Discuss with @gravitee-io/archi if there is an error in the way we behave in case of TransformationException in gravitee-gateway-api

[LiliaEn]

Tested on the 3.10.X env Browser: Chrome Version 98.0.4758.80 , macOS Big Sur v11.6 Works as expected.