Dimension Numeric Capture (Regex) Processors

George Alpizar
George Alpizar
  • Updated

Overview

This processor: 

  • Monitors a specific numerical field, such as latency, per unique dimension value, such as api_path
  • Automatically generate statistics, such as counts and averages
  • Detects anomalies, based on the aggregate values grouped by dimensions

Review Sample Configuration

Review the following sample configuration: 

regexes:
  - name: "http"
    pattern: "(?P<method>\\w+) took (?P<latency>\\d+) ms"
    dimensions: ["method"]
    trigger_thresholds:
      anomaly_probability_percentage: 90

Review Parameters

Review the following parameters that you can configure in the Edge Delta App.


name

Required

Enter a descriptive label for this processor. 

When you create a workflow, you will use this label to enter your processor into the workflow.

Review the following example:

name: "http-request-latencies"

pattern

Required

Enter a regular expression pattern with a named group.

The matching part of the log will be extracted and converted to a floating point. 

Named capture groups must follow Golang regex protocol, such as:

  • "(?P<latency>\\d+)ms"

Review the following example: 

pattern: "] \"(?P<method>\\w+) took (?P<latency>\\d+) ms"

dimensions

Optional

This parameter lists fields of named capture groups to use as dynamic dimensions (to group by).

For each dimension that you specify, you must have a corresponding named capture group in the pattern field for the processor.

Review the following example:

dimensions: ["method"] 

dimensions_as_attributes

Optional

Enter true or false to to send dimension key/value pairs as attributes.

If you enter false, then the dimension key/value pairs will be appended to the metric name. 

Note

If you enable this parameter, then you can specify the Dimensions Groups  parameter.

Review the following example:

dimensions_as_attributes: true 

interval

Optional

This parameter is a golang duration string that represents the reporting (or rollup) interval for the generated statistics.

The default value is 1m.

Review the following example:

interval: 2m 

enabled_stats

Optional

This parameter specifies the data generated from a regex rule. 

You can obtain the following values:

  • count
  • min
  • max
  • avg
  • anomaly1
  • anomaly2 

Review the following YAML example: 

enabled_stats: ["count", "anomalymin"]

Review the following PCT example: 

func allStats() []StatType {
    return []StatType{
	Anomaly1, Anomaly2, Avg, Count, Max, Min, P25, P75, P95, P99, StdDev, Sum,

retention

Optional

This parameter is a golang duration string that represents how far back the agent should look when generating anomaly scores.

The default value is 3h.

Review the following example:

retention: 4h 

trigger_thresholds

Optional

This parameter defines threshold limits, based on calculated metrics.

When a threshold is reached, the agent notifies the corresponding trigger destinations in the same workflow.

You can configure the following trigger threshold types:

  • anomaly_probability_percentage
  • upper_limit_per_interval
  • lower_limit_per_interval
  • consecutive

Review the following example:

trigger_thresholds: 
anomaly_probability_percentage: 90
upper_limit_per_interval: 250
consecutive: 5

anomaly_probability_percentage (trigger_thresholds)

Optional

This parameter sets the confidence level / probability of an anomaly that needs to be reached to trigger an alert. 

For example, if you enter 90, then an alert will trigger when there is a 90% probability that the detected pattern is an anomaly. 

Enter a number between 0 and 100.

There is no default value. 

Review the following example:  

trigger_thresholds: 
anomaly_probability_percentage: 90

upper_limit_per_interval (trigger_thresholds)

Optional

This parameter sets a static threshold to trigger an alert.  

If the number of events that match the given pattern for the most recent reporting interval is greater than the limit, then an alert will be triggered.

There is no default value. 

Review the following example:  

trigger_thresholds: 
upper_limit_per_interval: 250

lower_limit_per_interval (trigger_thresholds)

Optional

This parameter sets a static threshold to trigger an alert.

If the number of events that match the given pattern for the most recent reporting interval is less than the limit, then an alert will trigger.

There is no default value. 

Review the following example: 

trigger_thresholds: 
lower_limit_per_interval: 10

consecutive (trigger_thresholds)

Optional

This parameter sets how many consecutive times a threshold must be exceeded to trigger an alert.  

The default value is 0, which means that any condition that is met will trigger an alert. 

Review the following example:

trigger_thresholds: 
consecutive: 5

filters

Optional

Enter an existing filter to add to this processor. 

To learn how to create a filter, see Filters.

Review the following example:

filters:
- extract_severity

 


Review Sample Scenario 

To better understand how this processor works, review the following scenario: 

The following logs are fed into the processor: 

  • "GetAlbums took 12ms"
  • "GetRecords took 16ms"

When the agent sees these logs, the agent will generate the following metrics: 

  • http_method_getalbums_latency.count
  • http_method_getalbums_latency.avg
  • http_method_getalbums_latency.min
  • http_method_getalbums_latency.max
  • http_method_getalbums_latency.anomaly1
  • http_method_getrecords_latency.count
  • http_method_getrecords_latency.avg
  • http_method_getrecords_latency.min
  • http_method_getrecords_latency.max
  • http_method_getrecords_latency.anomaly1

Additionally, metrics are displayed in the following format:

  • {processor name}_{dimension name}_{dimension value}_{numeric capture group name}.{stat type}

For each distinct dimension (getalbums and getrecords), numeric statistics are calculated and reported with a metric name that contains the dimension.

If the above example had dimensions_as_attributes: true, then the metric name would not have been altered for each dimension value. Instead, the dimension value is added as an attribute. In this case, the following metrics would have been generated:

  • name: http_latency.count, attributes: {method="GetAlbums"}
  • name: http_latency.avg, attributes: {method="GetAlbums"}
  • name: http_latency.min, attributes: {method="GetAlbums"}
  • name: http_latency.max, attributes: {method="GetAlbums"}
  • name: http_latency.anomaly1, attributes: {method="GetAlbums"}
  • name: http_latency.count, attributes: {method="GetRecords"}
  • name: http_latency.avg, attributes: {method="GetRecords"}
  • name: http_latency.min, attributes: {method="GetRecords"}
  • name: http_latency.max, attributes: {method="GetRecords"}
  • name: http_latency.anomaly1, attributes: {method="GetRecords"}

 

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