[role="xpack"]
[[ml-configuring-url]]
=== Adding custom URLs to machine learning results

When you create an advanced job or edit any job in {kib}, you can optionally
attach one or more custom URLs. 

The custom URLs provide links from the anomalies table in the *Anomaly Explorer*
or *Single Metric Viewer* window in {kib} to {kib} dashboards, the *Discovery* 
page, or external websites. For example, you can define a custom URL that 
provides a way for users to drill down to the source data from the results set.

When you edit a job in {kib}, it simplifies the creation of the custom URLs for  
{kib} dashboards and the *Discover* page and it enables you to test your URLs. 
For example:

[role="screenshot"]
image::images/ml-customurl-edit.jpg["Edit a job to add a custom URL"]

For each custom URL, you must supply the URL and a label, which is the link text
that appears in the anomalies table. You can also optionally supply a time 
range. For example, these are the values that are added for `My link 1`:

[role="screenshot"]
image::images/ml-customurl-detail.jpg["An example of a label and URL"]

As in this case, the custom URL can contain 
<<ml-configuring-url-strings,dollar sign delimited tokens>>, which 
are populated when you click the link in the anomalies table. In this example, 
the custom URL contains `$earliest$`, `$latest$`, and `$service$` tokens, which 
pass the beginning and end of the time span of the selected anomaly and the 
pertinent `service` field value to the target page. If you were interested in the following anomaly, for example: 

[role="screenshot"]
image::images/ml-customurl.jpg["An example of the custom URL links in the Anomaly Explorer anomalies table"]

...clicking `My Link 1` opens the *Discover* page and shows results for the 
service and date that were identified in the anomaly:

[role="screenshot"]
image::images/ml-customurl-discover.jpg["An example of the results on the Discover page"]

Since we specified a time range of 2 hours, the time filter restricts the 
results to the time period two hours before and after the anomaly.

You can also specify these custom URL settings when you create or update jobs by 
using the {ml} APIs.

[float]
[[ml-configuring-url-strings]]
==== String substitution in custom URLs

You can use dollar sign ($) delimited tokens in a custom URL. These tokens are
substituted for the values of the corresponding fields in the anomaly records.
For example, for a configured URL of
`http://my.datastore.com/dashboards?user=$user_name$`, the value of the
`user_name` field in the anomaly record is substituted into the `$user_name$`
token when you click the link in the anomalies table.

NOTE: Not all fields in your source data exist in the anomaly results. If a
field is specified in the detector as the `field_name`, `by_field_name`,
`over_field_name`, or `partition_field_name`, for example, it can be used in a
custom URL. A field that is only used in the `categorization_field_name`
property, however, does not exist in the anomaly results.

The following keywords can also be used as tokens for string substitution in a
custom URL: `$earliest$`; `$latest$`; `$mlcategoryregex$`; `$mlcategoryterms$`.

The `$earliest$` and `$latest$` tokens pass the beginning and end of the time
span of the selected anomaly to the target page. The tokens are substituted with
date-time strings in ISO-8601 format. If you selected an interval of 1 hour for
the anomalies table, these tokens use one hour on either side of the anomaly
time as the earliest and latest times. The same is also true if the interval is
set to `Auto` and a one hour interval was chosen. You can override this behavior 
by using the `time_range` setting. 

The `$mlcategoryregex$` and `$mlcategoryterms$` tokens pertain to jobs where you
are categorizing field values. For more information about this type of analysis,
see <<ml-configuring-categories>>.

The `$mlcategoryregex$` token passes the regular expression value of the
category of the selected anomaly, as identified by the value of the `mlcategory`
field of the anomaly record.

The `$mlcategoryterms$` token likewise passes the terms value of the category of
the selected anomaly. Each categorization term is prefixed by a plus (+)
character, so that when the token is passed to a {kib} dashboard, the resulting
dashboard query seeks a match for all of the terms of the category.

For example, the following API updates a job to add a custom URL that uses 
`$earliest$`, `$latest$`, and `$mlcategoryterms$` tokens:

[source,js]
----------------------------------
POST _xpack/ml/anomaly_detectors/sample_job/_update
{
  "custom_settings": {
        "custom_urls": [
          {
            "url_name": "test-link1",
            "time_range": "1h",
            "url_value": "http://localhost:5601/app/kibana#/discover?_g=(refreshInterval:(display:Off,pause:!f,value:0),time:(from:'$earliest$',mode:quick,to:'$latest$'))&_a=(columns:!(_source),index:AV3OWB68ue3Ht69t29aw,interval:auto,query:(query_string:(analyze_wildcard:!t,query:'$mlcategoryterms$')),sort:!(time,desc))"
          }
        ]
      }
}
----------------------------------
//CONSOLE
//TEST[skip:setup:sample_job]

When you click this custom URL in the anomalies table in {kib}, it opens up the
*Discover* page and displays source data for the period one hour before and 
after the anomaly occurred. Since this job was categorizing log messages, some 
`$mlcategoryterms$` token values that were passed to the target page for an 
example anomaly are as follows:

[role="screenshot"]
image::images/ml-categoryterms.jpg["A query for category terms on the Discover page in {kib}"]

[TIP]
===============================
* The custom URL links in the anomaly tables use pop-ups. You must configure
your web browser so that it does not block pop-up windows or create an exception
for your {kib} URL.
* When creating a link to a {kib} dashboard, the URLs for dashboards can be very
long. Be careful of typos, end of line characters, and URL encoding. Also ensure
you use the appropriate index ID for the target {kib} index pattern.
* If you use an influencer name for string substitution, keep in mind that it
might not always be available in the analysis results and the URL is invalid in
those cases. There is not always a statistically significant influencer for each
anomaly.
* The dates substituted for `$earliest$` and `$latest$` tokens are in
ISO-8601 format and the target system must understand this format.
* If the job performs an analysis against nested JSON fields, the tokens for
string substitution can refer to these fields using dot notation. For example,
`$cpu.total$`.
* {es} source data mappings might make it difficult for the query string to work.
Test the custom URL before saving the job configuration to check that it works
as expected, particularly when using string substitution.
===============================