Function behavior when monitored URI does not contain wildcards
The following are the behaviors of the supported condition expression functions when the monitored URI does not contain wildcards—and thus points to one specific resource:
count
This function counts the number of distinct time-series data points that have been generated and implicitly reflects the "count" of data points collected at each data collection interval.
For example, applying the
count
function to the following URI results in a value of1
./rest/v1/system/subsystems/chassis/base?attributes=resource_utilization.cpu
sum
,min
,max
, andavg
Because there is just one resource, these aggregators return the current value of the resource. These aggregators only apply to resources represented by integers, such as number of packets received or CPU utilization.
- Aggregator
over time
When the keyword
over
follows one of the aggregators, the function behaves in a similar way but performs its aggregation "over" the specified time in the past instead of over the current value only.rate
The
rate
function calculates the per-second average rate of increase of the monitored resource.For example, applying the
rate
function to the following URI calculates the per-second average of the received packets on interface 1/1/5 for the last one minute:/rest/v1/system/interfaces/1%2F1%2F5?attributes=statistics.rx_packets per 1 minute
transition
The
transition
evaluates totrue
if the specified resource changes state as defined.The
transition
function only applies to columns of typeboolean
,enum
, andlist
.For example, the following expression is
true
when port 1/1/5 goes down:transition /rest/v1/system/ports/1%2F1%2F5?attributes=admin from "up" to "down"
ratio
The
ratio
function calculates the ratio between numerator and denominator of the specified resource.The
ratio
function only applies to columns of typeinteger
and has the restriction that the part of URI preceding the token '?' be the same. That is, theratio
function can calculate the ratio between two attributes of the same resource, but not between attributes of different resources.For example, to determine the ratio of the received packets to transmitted packets for interface 1/1/5, use the following expression:
ratio of /rest/v1/system/interfaces/1%2F1%2F5?attributes=statistics.rx_packets and /rest/v1/system/interfaces/1%2F1%2F5?attributes=statistics.tx_packets