Documentation Grafana Cloud Instrument and send data Grafana Alloy Reference Standard library json_path

json_path

The json_path function lookup values using jsonpath syntax.

The function expects two strings. The first string is the JSON string used look up values. The second string is the JSONPath expression.

json_path always returns a list of values. If the JSONPath expression doesn’t match any values, an empty list is returned.

A common use case of json_path is to decode and filter the output of a local.file or remote.http component to an Alloy syntax value.

Remember to escape double quotes when passing JSON string literals to json_path.

For example, the JSON value {"key": "value"} is properly represented by the string "{\"key\": \"value\"}".

Examples

Alloy Copy

> json_path("{\"key\": \"value\"}", ".key")
["value"]


> json_path("[{\"name\": \"Department\",\"value\": \"IT\"},{\"name\":\"TestStatus\",\"value\":\"Pending\"}]", "[?(@.name == \"Department\")].value")
["IT"]

> json_path("{\"key\": \"value\"}", ".nonexists")
[]

> json_path("{\"key\": \"value\"}", ".key")[0]
value