Language: Logging and Errors
The built-in functions print
and error
can be used for logging
and errors. Logging is helpful to understand how a policy is executing
in development. And errors are useful to halting execution immediately in
certain scenarios.
The print
function is used to output debug information. The exact location
where this print statements go is dependent on the host application and
the Sentinel runtime itself.
The print
function takes zero or more Sentinel values as arguments.
Each value is formatted for human-friendly output and space-separated.
Example:
Errors
Certain actions in Sentinel, such as accessing an undefined variable, attempting to add two incompatible types, etc. result in runtime errors. These errors halt the execution of a policy immediately. The pass/fail result of a policy is considered fail.
Runtime errors can be manually triggered using the error
function.
The error
function behaves exactly like the print
function except that
execution is halted immediately.
This should only be used in scenarios where the policy must fail due to
some unexpected or invalid condition. The line between error
and
undefined can sometimes be unclear. Undefined
is recommended when a policy can conceivably recover or safely ignore the
undefined behavior. An error should be used when the policy should fail and
notify someone regardless.