Update OPA Plugin: Error Handling and Synchronization with Plugin Framework Updates (#1531)

* Error handling and updates with new refactoring changes in plugin framework

Signed-off-by: Shriti Priya <shritip@ibm.com>

* update documentation

Signed-off-by: Shriti Priya <shritip@ibm.com>

* fixing lint issues

Signed-off-by: Shriti Priya <shritip@ibm.com>

* fixing linting issues

Signed-off-by: Shriti Priya <shritip@ibm.com>

* fixing lint issues

Signed-off-by: Shriti Priya <shritip@ibm.com>

* Fixing pylint issues

Signed-off-by: Shriti Priya <shritip@ibm.com>

* Replacing exception with pluginerror

Signed-off-by: Shriti Priya <shritip@ibm.com>

* Updating documentation and plugin code

Signed-off-by: Shriti Priya <shritip@ibm.com>

* fixing flake issues

Signed-off-by: Shriti Priya <shritip@ibm.com>

* fix lint issues

Signed-off-by: Shriti Priya <shritip@ibm.com>

* fix: correct f-string syntax in OPA plugin error logging

The f-string at line 225 had incorrect syntax with the colon and
variable inside the format specifier. Changed from:
  f"{OPAPluginErrorCodes.UNSUPPORTED_HOOK_TYPE.value: {hook}}"
to:
  f"{OPAPluginErrorCodes.UNSUPPORTED_HOOK_TYPE.value}: {hook}"

Signed-off-by: Mihai Criveti <crivetimihai@gmail.com>

---------

Signed-off-by: Shriti Priya <shritip@ibm.com>
Signed-off-by: Mihai Criveti <crivetimihai@gmail.com>
Co-authored-by: Mihai Criveti <crivetimihai@gmail.com>

Author: monshri

plugins/external/opa/README.md

@@ -275,6 +275,21 @@ make test
 The`make test` command executes a complete testing workflow: it launches an OPA server using the policy file located at ./opaserver/rego/policy.rego (as specified by `POLICY_PATH`), runs all test cases against this server, and automatically terminates the OPA server process once testing finishes.
 
 
+## Error Handling Verification
+
+1. `OPA_SERVER_NONE_RESPONSE` = "OPA server returned an empty response"
+2. `OPA_SERVER_ERROR` = "Error while communicating with the OPA server"
+3. `OPA_SERVER_UNCONFIGURED_ENDPOINT` = "Policy endpoint not configured on the OPA server"
+4. `UNSPECIFIED_REQUIRED_PARAMS` = "Required parameters missing: policy config, payload, or hook type"
+5. `UNSUPPORTED_HOOK_TYPE` = "Unsupported hook type (only tool, prompt, and resource are supported)"
+6. `INVALID_POLICY_ENDPOINT` = "Policy endpoint must be curated with the supported hooktypes"
+7. `UNSPECIFIED_POLICY_MODALITY` = "Unspecified policy modality. Picking up default modality: text"
+8. `UNSUPPORTED_POLICY_MODALITY` = "Unsupported policy modality (Supports text, image and resource)"
+9. `UNSPECIFIED_POLICY_PACKAGE_NAME` = "Unspecified policy package name"
+
+If OPA plugin encounters any of the errors above, it raises a PluginError.
+The file `test_errors.py` includes unit tests to verify that these errors are correctly raised under the corresponding conditions.
+Run it using `make test`
 
 ## License