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Caution

Grafana Alloy is the new name for our distribution of the OTel collector. Grafana Agent has been deprecated and is in Long-Term Support (LTS) through October 31, 2025. Grafana Agent will reach an End-of-Life (EOL) on November 1, 2025. Read more about why we recommend migrating to Grafana Alloy.

Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.

Open source

json_decode

The json_decode function decodes a string representing JSON into a River value. json_decode fails if the string argument provided cannot be parsed as JSON.

A common use case of json_decode is to decode the output of a local.file component to a River value.

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

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

Examples

> json_decode("15")
15

> json_decode("[1, 2, 3]")
[1, 2, 3]

> json_decode("null")
null

> json_decode("{\"key\": \"value\"}")
{
  key = "value",
}

> json_decode(local.file.some_file.content)
"Hello, world!"