Case statements

InfraSonar expressions use case statements to define conditional logic.

Boolean Comparisons

When working with boolean metrics (true or false), you can test their state directly:

case item.is_started:
    return DEBUG, "Service Started: @item.name"

To check for a false value or perform an explicit comparison:

case item.is_started == false:
    return DEBUG, "Service Not Started: @item.name"

Note: The == (equality) and != (inequality) operators can be used to explicitly compare any two values, including null, across all data types.

Numeric Comparisons

Numeric values can be compared using standard relational operators: == (equal to), != (not equal to), > (greater than), < (less than), >= (greater than or equal to), and <= (less than or equal to).

case item.count > 10:
    return DEBUG, "Count too large: @item.count"

String and List Membership

The in and not in operators are versatile for checking membership.

Substring Check

To test if a substring exists within a larger string:

case 'error' in item.message.lower():
    return ERROR, "Error in message: @item.message"

List Membership

To test if a value is present within a list of values:

case weekday in ['Saturday', 'Sunday']:
    return DEBUG, "It is weekend"

All elements within a single list must be of the same data type (e.g., all strings, all integers). You cannot mix types within the same list.