# Healthcheck

## Classification of health check errors

### Transient
Temporary errors due to some networking issues or load could be handled by the module itself through retries, processing request queue, emptying connection pool
 and etc.
As errors could lead to inconsistent state or unavailability, requests to the service should be avoided until the problem is fixed by module

Examples:
A database connection is broken, a connection pool is full, message broker connection is broken for a long time

### Manageable
Some errors that are not related to infrastructure problems but happen to be a result of some implementation or configuration errors in third-party service. Still could be fixed by module through retries.
As this kind of errors could impact all instances of the service it is very dangerous to avoid requests or stop service as it could lead to overall unavailability

Examples:
Configuration update parsing, external service response parsing error

### Fatal
Some errors could not be fixed by module, lead to service unavailability or to unaffordable inconsistent state.

Examples:
Initial state load error, connection to a database could not be established due to a configuration error, code unexpected errors