Flask App Usage

Lazy initialization

Use error_tracker.init_app method to configure

error_tracker = AppErrorTracker()
...
error_tracker.init_app(app=app, db=db, notifier=notifier)

Config details

• Enable or disable notification sending feature

  APP_ERROR_SEND_NOTIFICATION = False
  

• Email recipient list

  APP_ERROR_RECIPIENT_EMAIL = None
  

• Email subject prefix to be used by email sender

  APP_ERROR_SUBJECT_PREFIX = ""
  

• Mask value with following string

  APP_ERROR_MASK_WITH = "**************"
  

• Masking rule

  App can mask all the variables whose lower case name contains one of the configured string .. code:

  APP_ERROR_MASKED_KEY_HAS = ("password", "secret")
  

  Above configuration will mask the variable names like

  password
  secret
  PassWord
  THis_Is_SEcret
  

  Note

  Any variable names whose lower case string contains either password or secret

• Browse link in your service app

  List of exceptions can be seen at /dev/error, but you can have other prefix as well due to some securities or other reasons.

  APP_ERROR_URL_PREFIX = "/dev/error"
  

• Email address used to construct Message object

  APP_ERROR_EMAIL_SENDER = "prod-issue@example.com"
  

Manual Exception Tracking

Error can be tracked programmatically using AppErrorTracker’s capture_exception method. ErrorTracker provides many ways to capture error.

Capture Error using capture_exception method capture_exception takes another parameter for additional_context (dictionary of key value pairs). This parameter can be used to provide additional details about the failure.

error_tracker = AppErrorTracker(...)
...
try
    ...
catch Exception as e:
    error_tracker.capture_exception()

A simple Message can be captured using capture_message method.

try
    ...
catch Exception as e:
    error_tracker.capture_message("Something went wrong!")

Decorator based exception recording, record exception as it occurs in a method call.

Note

Exception will be re-raised so it must be caught in the caller or ignored. Raised exception can be ignored by passing silent=True. Also more context detail can be provided using additional_context parameter.

@error_tracker.auto_track_exception
def fun():
    pass

So far, you have seen only uses where context is provided upfront using default context builder or some other means. Sometimes, we need to put context based on the current code path, like add user_id and email in login flow. ErrorTracker comes with context manager that can be used for such use cases.

from error_tracker import flask_scope

with flask_scope() as scope:
    scope.set_extra("user_id", 1234)
    scope.set_extra("email", "example@example.com" )

Now error_tracker will automatically capture exception as it will occur. This data will be stored in request_data detail as

{
   ...
    "context" : {
        "id" : 1234,
        "email" :  "example@example.com"
    }
}