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Trigger

The Trigger Action compares the contents of a field from an incoming Event with predefined rules, when the rules match, an Event emit is triggered.

Use the Trigger Action to ignore Events that don't require processing; to send Events downstream for additional analysis; to further process events that are sent from a particular application.

Features

  • Trigger an Event emit based on the following:
    • regex: The contents of a field at a defined path match a defined regular expression.
    • !regex: The contents of a field at a defined path do not match a defined regular expression.
    • field<value: The number in a field at a defined path is less than a specified value.
    • field<=value: The number in a field at a defined path is less than or equal to a specified value.
    • field==value: The number in a field at a defined path is equal to a specified value.
    • field!=value: The number in a field at a defined path is not equal to a specified value.
    • field>=value: The number in a field at a defined path is greater than or equal to a specified value.
    • field>value: The number in a field at a defined path is greater than a specified value.
    • in: The value specified is contained in a field at a defined path.
    • not in: The value specified is not contained in a field at a defined path.
  • Regex patterns are matched case-insensitive.
  • The value can be a single value or an array of values. In the case of an array, all items must be strings, and if one or more values match, then the rule matches.

Configuration Options

  • rules: The rules array contains sets of type, path and value fields.
    • type: Chose one of 'regex', '!regex', 'field<value', 'field<=value', 'field==value', 'field!=value', 'field>=value', 'field>value', 'in', and 'not in' and compares with the value
    • path: Specify the wrapped JSONPath for the field containing the value to compare. When an incoming event contains an array, a wildcard (e.g.: numbers[*]) can be supplied to apply the rule to all elements of the array.
    • value: Specify regex, number, or array depending on the match type.
  • must_match: (Optional) By default, all rules must match for the Action to trigger an Event emit. You can switch this so that only one rule must match by setting must_match to '1'.
  • emit_no_match: (Optional) By default, an event will only be emitted if the rules match. By setting emit_no_match to true an event will also be emitted if the rules do not match.

Emitted Events

When a rule is matched, Events emitted by the Trigger Action will contain a field named rule_matched set to "true".

{
"rule_matched": true
}

When a rule is not matched and emit_no_match is configured, Events will be emitted by the Trigger Action and will contain a field named rule_matched set to "false".

{
"rule_matched": false
}

Example Configuration Options

Emit an Event when the contents of the 'size' field in an incoming Events are greater than 5.

{
"rules": [
{
"type": "field>value",
"path": "{{.size}}",
"value": "5"
}
]
}

Emit an Event when the content of the 'body' field contain an email address.

{
"rules": [
{
"type": "regex",
"path": "{{.body}}",
"value": "\\b[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,4}\\b"
}
]
}

Emit an event when 'dog' is found in the array of animal types listed in path.

{
"rules": [
{
"type": "in",
"path": ["dog", "bird", "turtle"],
"value": "dog"
}
]
}

Value can also be an array. In this case the action will emit an event when either 'dog' or 'cat' is found in the array of animal types listed in path.

{
"rules": [
{
"type": "in",
"path": ["dog", "bird", "turtle"],
"value": ["dog", "cat"]
}
]
}

Emit an Event when 'dog' is not contained in the array of animal types listed in path.

{
"rules": [
{
"type": "not in",
"path": ["bird", "turtle"],
"value": "dog"
}
]
}

Value can also be an array. In this case it means that neither 'dog' nor 'cat' are contained in the array of animal types listed in path.

{
"rules": [
{
"type": "not in",
"path": ["bird", "turtle"],
"value": ["dog", "cat"]
}
]
}

Emit an Event when the contents of the 'size' field of an incoming Event is greater than 0 AND the contents of the 'username' field is "alice".

{
"rules": [
{
"type": "field>value",
"path": "{{.size}}",
"value": 0
},
{
"type": "field==value",
"path": "{{.username}}",
"value": "alice"
}
]
}

Emit an Event when the contents of the 'size' field of an incoming Event is greater than 0 OR the contents of the 'username' field is "alice".

{
"rules": [
{
"type": "field>value",
"path": "{{.size}}",
"value": 0
},
{
"type": "field==value",
"path": "{{.username}}",
"value": "alice"
}
],
"must_match": 1
}

When receiving the following event:

{
"students": [
{
"name": "Alice",
"age": "20"
},
{
"name": "Bob",
"age": "33"
},
{
"name": "Carol",
"age": "29"
}
]
}

Emit an event if any of the students are over 25 years of age:

{
"rules": [
{
"type": "field>value",
"value": "25",
"path": "{{.students[*].age}}"
}
],
"must_match": "1"
}