Monitoring Functions

The Gateway component exposes several metrics to help you monitor the health and behavior of your functions

Metric	Type	Description	Labels
gateway_functions_seconds	histogram	Function invocation time taken	function_name
gateway_function_invocation_total	counter	Function invocation count	function_name, code
gateway_service_count	counter	Number of function replicas	function_name

Examples

These basic metrics can be used to track the health of your functions as well a general usage patterns. See the Prometheus documentation and examples for more details about the available options and query functions. Below are several queries you might want to include in a basic Grafana dashboard for observing your OpenFaaS functions

Function invocation rate

Return the per-second rate of invocation as measured over the previous 20 seconds:

rate ( gateway_function_invocation_total [20s])

Function replica count / scaling

Return the total function replicas:

gateway_service_count

Total OK Function Invocation

Return the total number of successful function invocations:

sum( gateway_function_invocation_total {  code=\"200\"}

Function execution time

Return the average function execution time, as measure over the previous 20 seconds:

(rate(gateway_functions_seconds_sum[20s]) / rate(gateway_functions_seconds_count[20s]))

Metrics for a single function

Each of the metrics generated by the Gateway are labeled with and can be filtered by the function name, For example The invocation rate for just a single function (e.g. if the function name is echo) is given by

rate ( gateway_function_invocation_total{function_name='echo'} [20s])