Logging

Fhirbug’s RequestHandlers all have a method called log_request that is called whenever a request is done being proccessed with several information about the request.

By default, this method returns an AuditEvent FHIR resource instance populated with available information about the request.

Enhancing or persisting the default handler

Enhancing the generated AuditEvents with extra information about the request and Persisiting them is pretty simple. Just use custom RequestHandlers and override the log_request method:

from fhirbug.Fhir.resources import AuditEventEntity
from fhirbug.config import import_models

class EnhancedLoggingMixin:
    def log_request(self, *args, **kwargs):
        audit_event = super(EnhancedLoggingMixin, self).log_request(*args, **kwargs)

        context = kwargs["query"].context
        user = context.user
        # We populate the entity field with info about the user
        audit_event.entity = [
            AuditEventEntity({
                "type": {"display": "Person"},
                "name": user.username,
                "description": user.userid,
            })
        ]
        return audit_event


class PersistentLoggingMixin:
    def log_request(self, *args, **kwargs):
        audit_event = super(PersistentLoggingMixin, self).log_request(*args, **kwargs)
        models = import_models()
        AuditEvent = getattr(models, 'AuditEvent')
        audit_event_model = AuditEvent.create_from_resource(audit_event)
        return audit_event

# Create the handler
class CustomGetRequestHandler(
    PersistentLoggingMixin, EnhancedLoggingMixin, GetRequestHandler
):
    pass

Note

In order to have access to the user instance we assume you have passed a query context to the request handler’s handle method containing the necessary info

Note

Note that the order in which we pass the mixins to the custom handler class is important. Python applies mixins from right to left, meaning PersistentLoggingMixin’s super() method will call EnhancedLoggingMixin’s log_request and EnhancedLoggingMixin’s super() method will call GetRequestHandler’s

So, we expect the AuditEvent that is persisted by the PersistentLoggingMixin to contain information about the user because it is comes before EnhancedLoggingMixin in the class definition

Creating a custom log handler

If you don’t want to use fhirbug’s default log handling and want to implement something your self, the process is pretty much the same. You implement your own log_request method and process the information that is passed to it by fhirbug any way you want. Essentially the only difference with the examples above is that you do not call super() inside your custom log function.

The signature of the log_request function is the following:

AbstractRequestHandler.log_request(self, url, query, status, method, resource=None, OperationOutcome=None, request_body=None, time=datetime.now())

Create an AuditEvent resource that contains details about the request.

Parameters:

• url (string) – The initial url that was requested
• query (FhirRequestQuery) – The FhirRequestQuery that was generated
• status (int) – The status code that was returned
• method (string) – The request method
• resource (FhirResource) – A Fhir resource, possibly a bundle, of the resources that were accessed or modified during the request
• OperationOutcome (OperationOutcome) – An OperationOutcome related to the requset
• request_body – The body of the request
• time (datetime) – The time the request occured

Here’s an example where we use python’s built-in logging module:

from datetme import datetime
from logging import getLogger

logger = getLogger(__name__)

class CustomGetRequestHandler(GetRequestHandler):
    def log_request(self, url, status, method, *args, **kwargs):
        logger.info("%s: %s %s %s" % (datetime.now(), method, url, status))