Add Observation implementation

[johkin]

Initial implementation of observation for spring-ws.

Please feel free to comment and provide feedback.

#1094

[johkin]

Ping @corneil

[corneil]

@johkin Thanks for this great contribution.
I would suggest adding something like: Assert.notNull(observation, "Expected observation in messageContext"); at appropriate places.

[shakuzen]

Thank you for the work on this. It's a very complete pull request. I left some feedback for consideration.

[johkin]

I did some minor restructuring of the code to improve readability and error-handling/logging.

The method used to find the root element is identical in both interceptors, could be and improvement to refactor this to a helper-class? On the other hand, this requires the helper to be injected in the interceptors and creates another dependency.

[shakuzen]

Should this be public or can it be package-private?

[shakuzen]

Oops. I was looking at old commits.

[shakuzen]

Is there a reason to have multiple instances of this class? Could it be a singleton utility class instead?

[shakuzen]

Or alternatively, could the public method be static and it not have a public constructor?

[johkin]

It could certainly be a singleton, is something like this what you had in mind:
`java

private static ObservationHelper INSTANCE;

public static ObservationHelper getInstance() {
    if (INSTANCE == null) {
        INSTANCE = new ObservationHelper();
    }
    return INSTANCE;
}

private ObservationHelper() {

`

Also noted that a minor bug slipped through the tests, I have a fix in place locally.

[shakuzen]

Yes, that would be one option. I'll leave it up to @corneil to advise on what makes most sense given existing patterns used in this codebase.

[corneil]

@johkin when I checkout the PR and run ./mvnw clean package there are test failures:

[ERROR] Failures: 
[ERROR]   WebServiceTemplateObservationIntegrationTest.attachment:305 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='null', lowCardinalityKeyValues=[exception='none', host='localhost', localpart='unknow', namespace='unknown', outcome='success', soapaction='none'], highCardinalityKeyValues=[path='/soap/attachment'], map=[], parentObservation=null
[ERROR]   WebServiceTemplateObservationIntegrationTest.marshalSendAndReceiveNoResponse:222 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='null', lowCardinalityKeyValues=[exception='none', host='localhost', localpart='unknow', namespace='unknown', outcome='success', soapaction='none'], highCardinalityKeyValues=[path='/soap/noResponse'], map=[], parentObservation=null
[ERROR]   WebServiceTemplateObservationIntegrationTest.notFound:241 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='org.springframework.ws.client.WebServiceTransportException: Server Error [500]', lowCardinalityKeyValues=[exception='WebServiceTransportException', host='localhost', localpart='unknow', namespace='unknown', outcome='fault', soapaction='none'], highCardinalityKeyValues=[path='/errors/notfound'], map=[], parentObservation=null
[ERROR]   WebServiceTemplateObservationIntegrationTest.receiverFault:262 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='org.springframework.ws.soap.client.SoapFaultClientException: Receiver Fault', lowCardinalityKeyValues=[exception='SoapFaultClientException', host='localhost', localpart='unknow', namespace='unknown', outcome='fault', soapaction='none'], highCardinalityKeyValues=[path='/soap/receiverFault'], map=[], parentObservation=null
[ERROR]   WebServiceTemplateObservationIntegrationTest.sendSourceAndReceiveToResult:158 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='null', lowCardinalityKeyValues=[exception='none', host='localhost', localpart='unknow', namespace='unknown', outcome='success', soapaction='none'], highCardinalityKeyValues=[path='/soap/echo'], map=[], parentObservation=null
[ERROR]   WebServiceTemplateObservationIntegrationTest.sendSourceAndReceiveToResultNoResponse:177 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='null', lowCardinalityKeyValues=[exception='none', host='localhost', localpart='unknow', namespace='unknown', outcome='success', soapaction='none'], highCardinalityKeyValues=[path='/soap/noResponse'], map=[], parentObservation=null
[ERROR]   WebServiceTemplateObservationIntegrationTest.senderFault:282 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.client', contextualName='POST', error='org.springframework.ws.soap.client.SoapFaultClientException: Sender Fault', lowCardinalityKeyValues=[exception='SoapFaultClientException', host='localhost', localpart='unknow', namespace='unknown', outcome='fault', soapaction='none'], highCardinalityKeyValues=[path='/soap/senderFault'], map=[], parentObservation=null
[ERROR]   ObservationInterceptorIntegrationTest.testObservationInterceptorBehavior:102 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.server', contextualName='POST /ws/{pathInfo}', error='null', lowCardinalityKeyValues=[exception='none', localpart='unknow', namespace='unknown', outcome='success', path='/ws/{pathInfo}', soapaction='none'], highCardinalityKeyValues=[pathinfo='/1234'], map=[], parentObservation=null,name='webservice.server', contextualName='POST /ws', error='null', lowCardinalityKeyValues=[exception='none', localpart='unknow', namespace='unknown', outcome='success', path='/ws', soapaction='none'], highCardinalityKeyValues=[], map=[], parentObservation=null
[ERROR]   ObservationInterceptorIntegrationTest.testPathWithVariable:125 There should be at least one Observation that matches the assertion. Found following Observations:
name='webservice.server', contextualName='POST /ws/{pathInfo}', error='null', lowCardinalityKeyValues=[exception='none', localpart='unknow', namespace='unknown', outcome='success', path='/ws/{pathInfo}', soapaction='none'], highCardinalityKeyValues=[pathinfo='/1234'], map=[], parentObservation=null

[johkin]

Yes, I noticed the test-failures yesterday. I've updated the code to handle the issue correctly.