> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chronosphere.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Parse

export const entity_0 = "parse processing rule"

The parse [processing rule](/ingest/pipeline/processing-rules) uses a regular
expression to search for values inside a string and to assign a key to each value,
then stores those key/value pairs in a structured object. Additionally, the
resulting output always includes the original string.

## Configuration parameters

Use the parameters in this section to configure the {entity_0}. The
Telemetry Pipeline web interface uses the items in the **Name** column to
describe these parameters. [Pipeline configuration files](/ingest/pipeline/v2/configure/config-files)
use the items in the **Key** column as YAML keys.

| Name                | Key           | Description                                                                                                                                                                          | Default |
| ------------------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------- |
| **Source key**      | `src`         | Required. The key whose value contains data to parse.                                                                                                                                | *none*  |
| **Destination key** | `dst`         | Required. The key of the object to store your structured key/value pairs. This rule can't overwrite an existing key, so this value must be a unique name within your telemetry data. | *none*  |
| **Regex**           | `regex`       | Required. The regular expression for extracting values from the value of **Source key** and assigning keys to those values.                                                          | *none*  |
| **Regex engine**    | `regexEngine` | Required. The [engine](/ingest/pipeline/processing-rules#regex-engines) to parse your regular expression. Accepted values: `GNU`, `Oniguruma`, `PCRE2`, `POSIX`, `TRE`.              | `PCRE2` |
| **Comment**         | `comment`     | A 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*  |

## GPT generation

<Note>
  Keep in mind that this feature is experimental, and that Chronosphere can't guarantee
  the accuracy or quality of generated scripts.

  To enable or disable GPT generation, see
  [Project settings](/ingest/pipeline/administer/project-settings#enable-or-disable-gpt-generation).
</Note>

The parse processing rule lets you generate regular expressions by using a
generative pre-trained transformer (GPT). To use this feature, click **Generate
Regular Expression With Gpt Experimental**. GPT generation uses any logs present
in the **Input** field of the processing rules builder as the basis for its
prompt.

## Example

Using the parse processing rule lets you extract any data from a string and
turn that data 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 logs:

```json theme={null}
{"log":"198.143.234.244 - - [18/Mar/2012:13:55:36 -0700] \"GET /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.3; Trident/4.0)\""}
{"log":"66.216.63.42 - Lucille [18/Mar/2012:15:07:29 -0700] \"DELETE /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_3; like Mac OS X) AppleWebKit/533.11 (KHTML, like Gecko)  Chrome/52.0.3189.332 Mobile Safari/536.3\""}
{"log":"70.137.97.47 - - [18/Mar/2012:19:21:04 -0700] \"GET /lease.pdf HTTP/1.0\" 404 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.3; Trident/4.0)\""}
{"log":"7.160.29.68 - Michael [19/Mar/2012:01:38:17 -0700] \"POST /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (U; Linux i585 x86_64; en-US) Gecko/20130401 Firefox/60.7\""}
{"log":"31.119.193.169 - - [19/Mar/2012:08:33:29 -0700] \"GET /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (iPad; CPU iPad OS 7_9_0 like Mac OS X) AppleWebKit/602.13 (KHTML, like Gecko)  Chrome/50.0.2327.233 Mobile Safari/534.2\""}
```

A processing rule with the **Source key** value `log`, the **Destination key**
value `parsed`, the **Regex** value
`^(?<host>[^ ]*) [^ ]* (?<user>[^ ]*) \[(?<time>[^\]]*)\] "(?<method>\S+)(?: +(?<path>[^ ]*) +\S*)?" (?<code>[^ ]*) (?<size>[^ ]*)(?: "(?<referer>[^\"]*)" "(?<agent>.*)")?$`, and the **Regex engine**
value `PCRE2` returns the following result:

```json theme={null}
{"parsed":{"host":"198.143.234.244","time":"18/Mar/2012:13:55:36 -0700","path":"/lease.pdf","code":"200","user":"-","agent":"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.3; Trident/4.0)","method":"GET","referer":"bluth-homes.oc","size":"5689972"},"log":"198.143.234.244 - - [18/Mar/2012:13:55:36 -0700] \"GET /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.3; Trident/4.0)\""}
{"parsed":{"host":"66.216.63.42","time":"18/Mar/2012:15:07:29 -0700","path":"/lease.pdf","code":"200","user":"Lucille","agent":"Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_3; like Mac OS X) AppleWebKit/533.11 (KHTML, like Gecko)  Chrome/52.0.3189.332 Mobile Safari/536.3","method":"DELETE","referer":"bluth-homes.oc","size":"5689972"},"log":"66.216.63.42 - Lucille [18/Mar/2012:15:07:29 -0700] \"DELETE /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_3; like Mac OS X) AppleWebKit/533.11 (KHTML, like Gecko)  Chrome/52.0.3189.332 Mobile Safari/536.3\""}
{"parsed":{"host":"70.137.97.47","time":"18/Mar/2012:19:21:04 -0700","path":"/lease.pdf","code":"404","user":"-","agent":"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.3; Trident/4.0)","method":"GET","referer":"bluth-homes.oc","size":"5689972"},"log":"70.137.97.47 - - [18/Mar/2012:19:21:04 -0700] \"GET /lease.pdf HTTP/1.0\" 404 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.3; Trident/4.0)\""}
{"parsed":{"host":"7.160.29.68","time":"19/Mar/2012:01:38:17 -0700","path":"/lease.pdf","code":"200","user":"Michael","agent":"Mozilla/5.0 (U; Linux i585 x86_64; en-US) Gecko/20130401 Firefox/60.7","method":"POST","referer":"bluth-homes.oc","size":"5689972"},"log":"7.160.29.68 - Michael [19/Mar/2012:01:38:17 -0700] \"POST /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (U; Linux i585 x86_64; en-US) Gecko/20130401 Firefox/60.7\""}
{"parsed":{"host":"31.119.193.169","time":"19/Mar/2012:08:33:29 -0700","path":"/lease.pdf","code":"200","user":"-","agent":"Mozilla/5.0 (iPad; CPU iPad OS 7_9_0 like Mac OS X) AppleWebKit/602.13 (KHTML, like Gecko)  Chrome/50.0.2327.233 Mobile Safari/534.2","method":"GET","referer":"bluth-homes.oc","size":"5689972"},"log":"31.119.193.169 - - [19/Mar/2012:08:33:29 -0700] \"GET /lease.pdf HTTP/1.0\" 200 5689972 \"bluth-homes.oc\" \"Mozilla/5.0 (iPad; CPU iPad OS 7_9_0 like Mac OS X) AppleWebKit/602.13 (KHTML, like Gecko)  Chrome/50.0.2327.233 Mobile Safari/534.2\""}
```

This rule extracted values from the string stored in the `log` key, assigned a key
to each value, then stored the resulting key/value pairs in a new structured object
named `parsed`.

## Related rules

This rule is a modified version of the [parsers](/ingest/pipeline/v2/build/parsers) feature.

For a processing rule that performs a similar operation on embedded data already
formatted as key/value pairs, see [extract keys/values](/ingest/pipeline/processing-rules/extract-keys-values).