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The decode JSON processing rule transforms an escaped JSON string into a structured JSON object. The resulting output includes both the original string and a new JSON object assigned to the key of your choosing.

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Configuration parameters

Use the parameters in this section to configure the . The Telemetry Pipeline web interface uses the items in the Name column to describe these parameters. Pipeline configuration files use the items in the Key column as YAML keys.
NameKeyDescriptionDefault
Source keysrcRequired. The key that contains the escaped JSON string to transform.log
Destination keydstRequired. The key to store your transformed JSON object. If a key with this name already exists, the decode JSON rule will overwrite it.decoded_json
CommentcommentA custom note or description of the rule’s function. This text is displayed next to the rule’s name in the Actions list in the processing rules interface.none

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Example

Using the decode JSON rule lets you extract embedded data from a string and turn it into parsable key/value pairs. You can then use these key/value pairs in other processing rules or for general storage and analysis. For example, given the following sample website log data: 
{"log": "{\"timestamp\":\"2023-03-28T09:08:41.64283645Z\",\"user_id\":3,\"page_id\":30,\"action\":\"purchase\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:08:42.643343109Z\",\"user_id\":4,\"page_id\":10,\"action\":\"purchase\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:08:48.643600498Z\",\"user_id\":1,\"page_id\":50,\"action\":\"click\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:08:50.643773688Z\",\"user_id\":5,\"page_id\":40,\"action\":\"purchase\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:08:51.643932272Z\",\"user_id\":1,\"page_id\":30,\"action\":\"purchase\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:08:56.644080944Z\",\"user_id\":2,\"page_id\":40,\"action\":\"click\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:09:03.64425954Z\",\"user_id\":3,\"page_id\":30,\"action\":\"click\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:09:03.644317046Z\",\"user_id\":1,\"page_id\":20,\"action\":\"view\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:09:10.64447719Z\",\"user_id\":2,\"page_id\":50,\"action\":\"purchase\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:09:17.644810963Z\",\"user_id\":2,\"page_id\":10,\"action\":\"view\"}\n"}
{"log": "{\"timestamp\":\"2023-03-28T09:09:20.644994805Z\",\"user_id\":1,\"page_id\":50,\"action\":\"view\"}\n"}
A processing rule with the Source key value log and the Destination key value output returns the following result: 
{"output":{"page_id":30,"action":"purchase","timestamp":"2023-03-28T09:08:41.64283645Z","user_id":3},"log":"{\"timestamp\":\"2023-03-28T09:08:41.64283645Z\",\"user_id\":3,\"page_id\":30,\"action\":\"purchase\"}\n"}
{"output":{"page_id":10,"action":"purchase","timestamp":"2023-03-28T09:08:42.643343109Z","user_id":4},"log":"{\"timestamp\":\"2023-03-28T09:08:42.643343109Z\",\"user_id\":4,\"page_id\":10,\"action\":\"purchase\"}\n"}
{"output":{"page_id":50,"action":"click","timestamp":"2023-03-28T09:08:48.643600498Z","user_id":1},"log":"{\"timestamp\":\"2023-03-28T09:08:48.643600498Z\",\"user_id\":1,\"page_id\":50,\"action\":\"click\"}\n"}
{"output":{"page_id":40,"action":"purchase","timestamp":"2023-03-28T09:08:50.643773688Z","user_id":5},"log":"{\"timestamp\":\"2023-03-28T09:08:50.643773688Z\",\"user_id\":5,\"page_id\":40,\"action\":\"purchase\"}\n"}
{"output":{"page_id":30,"action":"purchase","timestamp":"2023-03-28T09:08:51.643932272Z","user_id":1},"log":"{\"timestamp\":\"2023-03-28T09:08:51.643932272Z\",\"user_id\":1,\"page_id\":30,\"action\":\"purchase\"}\n"}
{"output":{"page_id":40,"action":"click","timestamp":"2023-03-28T09:08:56.644080944Z","user_id":2},"log":"{\"timestamp\":\"2023-03-28T09:08:56.644080944Z\",\"user_id\":2,\"page_id\":40,\"action\":\"click\"}\n"}
{"output":{"page_id":30,"action":"click","timestamp":"2023-03-28T09:09:03.64425954Z","user_id":3},"log":"{\"timestamp\":\"2023-03-28T09:09:03.64425954Z\",\"user_id\":3,\"page_id\":30,\"action\":\"click\"}\n"}
{"output":{"page_id":20,"action":"view","timestamp":"2023-03-28T09:09:03.644317046Z","user_id":1},"log":"{\"timestamp\":\"2023-03-28T09:09:03.644317046Z\",\"user_id\":1,\"page_id\":20,\"action\":\"view\"}\n"}
{"output":{"page_id":50,"action":"purchase","timestamp":"2023-03-28T09:09:10.64447719Z","user_id":2},"log":"{\"timestamp\":\"2023-03-28T09:09:10.64447719Z\",\"user_id\":2,\"page_id\":50,\"action\":\"purchase\"}\n"}
{"output":{"page_id":10,"action":"view","timestamp":"2023-03-28T09:09:17.644810963Z","user_id":2},"log":"{\"timestamp\":\"2023-03-28T09:09:17.644810963Z\",\"user_id\":2,\"page_id\":10,\"action\":\"view\"}\n"}
{"output":{"page_id":50,"action":"view","timestamp":"2023-03-28T09:09:20.644994805Z","user_id":1},"log":"{\"timestamp\":\"2023-03-28T09:09:20.644994805Z\",\"user_id\":1,\"page_id\":50,\"action\":\"view\"}\n"}
This rule retained the original log string and created a new JSON object called output that contains a structured version of the same key/value pairs that are embedded in log. For a processing rule with the opposite effect, see encode JSON. For a processing rule with a similar effect that works for any string, see extract keys/values.