Reference to the aliasSource() function


aliasSource (<expression>, [metric|source|{tagk, <pointTagKey>},]
            <zeroBasedNodeIndex> [, "<delimiterDefinition>"])

aliasSource (<expression>, [metric|source|{tagk, <pointTagKey>},]
            “<regexSearchPattern>”, "<replacementPattern>")

aliasSource (<expression>, "<newSourceName>")

Replace one or more source names in a ts() expression with a string extracted from the metric name(s), source name(s), or point tag value(s).


expression The ts() expression to extract a string from.
metric|source|{tagk,<pointTagKey>} The set of data to extract the new source name from.
  • Use {tagk, <pointTagKey>} if you want to extract a node from an existing point tag value. To use this approach, enter tagk followed by the point tag key.
    For example, if you have point tag Region=us-west-2b, and you want to replace the existing metric name with the entire point tag value, enter tagk, Region and set zeroBasedNodeIndex to 0.
  • If you don't specify (metric, source, or tagk), this parameter defaults to source.
zeroBasedNodeIndex, "delimiterDefinition" Use these parameters if you want to extract a single node from an existing source name, metric name, or point tag value and use it as the new source name.
  • zeroBasedNodeIndex - Node to extract from the selected source name, metric name, or point tag value. This node is then used as the new source name.
  • delimiterDefinition - Use this optional parameter to specify a delimiter other than period ("."). For example, to extract total_environment from, set zeroBasedNodeIndex to 2 and "delimiterDefinition" to "-". If no "delimiterDefinition" is specified, then only periods (".") are considered delimiters.
"regexSearchPattern", "replacementPattern" Use these parameters if you want to use regular expression search and replacement patterns from an existing source name, metric name, or point tag value as the new source name.
  • "regexSearchPattern" - A regular expression pattern to match against the source name, metric name or point tag value.
  • "replacementPattern" - The replacement string. If capturing groups are used in regexSearchPattern, they can be referred to as $1, $2, etc.
"newSourceName" Use this parameter to specify a new static value to use as the new source name. If more than 1 source is part of expression, a new synthetic point tag named _discriminant will be included in the results to separate each original source.


aliasSource() lets you replace one or more existing source names in a ts() expression with a string extracted from the metric name(s), source name(s), or point tag value(s). For example, let’s say you have a set of metrics that includes the customer name:


The set of metrics is being reported by 1 source (e.g. source1) – what if you wanted to aggregate the data and group by customer? You could create two separate ts() expressions, or you could instead use aliasSource() to update the <source1> name to customerA or customerB. You could then group by source and get the answer you need from a single expression.

Starting with release 2018.22, source names are converted to lowercase to maintain consistent behavior for series matching. When you use aliasSource() with a static string (e.g. aliasSource(ts(<>), "Source.Test"), source names retain their original case.

The aliasSource() function supports several ways of replacing source names in a ts() expression: zeroBasedNodeIndex, regular expression replacement, simple string replacement.

zeroBasedNodeIndex Approach

When you use the zeroBasedNodeIndex approach for aliasSource(), you extract a single node from an existing source name, metric name, or point tag value and use that node to rename a source.

Nodes in existing source name(s), metric name(s), or point tag value(s) are separated by delimiters. For example, let’s say that you have the following metric name:

In the metric name above, each node is assigned a number:

node node number
disk 0
space 1
total 2
environment 3

The node numbers can be associated with the zeroBasedNodeIndex parameter.

By default, Wavefront identifies each node separated by a (“.”) delimiter. If the metric name is:

Then each node is assigned the following number:

disk = 0
space-total_environment = 1

If the data you want to extract a node from include delimiters such as a hyphen (“-“) or underscore (“_”), then you can use the "delimiterDefinition" parameter to identify those delimiters.

See the examples below for details.

Regex Approach

You can also use a regular expression with aliasSource() to transform an existing source name, metric name, or point tag value. This approach works as a “search-replace” functionality—everything that matches regexSearchPattern is replaced with replacementPattern. See the examples below for details.

Improving Readability by Manipulating the Output

All metadata functions support inserting the value of the metric, source or tags in replacement strings via the <entity> syntax.

For example:

aliasSource(ts(aws.instance.price), "{{Region}}-{{source}}")

Adds the value of the region tag and a hyphen to the original source.

That means mycluster-2c-ha2-i-00e421d1bef7fb88e is converted to us-west-2-mycluster-2c-ha2-i-00e421d1bef7fb88e if the source is us-west-2.


The following examples show how to use aliasSource with a zeroBasedNodeIndex.

zeroBasedNodeIndex Example 1 - Renaming source(s) with an existing source name node

Assume that your base expression ts("requests.failures.num") has 40 unique sources sending data. Those 40 unique sources are named app-1, app-2, app-3app-40.


In this example, you’d like to ignore the app reference in the existing source name, and display only the number as the source name. You can do that with the following expression:



  • You don’t need to specify a source parameter because you are extracting a node from an existing source name and the default is source.
  • The "delimiterDefinition" parameter specifies hyphen (-) as a delimiter because this source name uses hyphens (“-“) as delimiters.
  • The zeroBasedNodeIndex of 1 extracts only the number and drops the string. The pattern is app-<number>, that is, app = 0 and <number> = 1.

zeroBasedNodeIndex Example 2 - Renaming Source(s) with a Metric Name

This example assumes 1 physical server running 8 virtual machines. Each virtual machine is sending stats into Wavefront. The source name is the physical server. The unique virtual machine name is only in the metric name:


To see the virtual machine name instead of the physical server name as the source name, you can use aliasSource:

aliasSource(ts(*),metric, 3)
  • You set the second parameter to metric because you want to extract the string from the metric name.
  • You don’t have to specify a delimiterDefinition because the metric name uses only periods as delimiters.
  • You set zeroBasedNodeIndex to 3 because the VM name has that index in

This approach replaces phyServ with vm1, vm2, vm3, etc. for each unique metric.

zeroBasedNodeIndex Example 3 - Renaming Source(s) with a Point Tag Value

Assume that you have 5 unique servers (server1, server2, server3, etc.) that run multiple applications. A set of general metrics such as application.latency, applies to all applications. You apply an application point tag to the data format to determine the associated application for each source on a chart. The format of the application point tag is:


For this use case, you’d like to replace the existing source names (server1, server2, server3, etc.) with the id value and application name. You use the following expression:

aliasSource(ts("application.latency"), tagk, application, 2, ".-")

In the example above:

  • You want to extract a new source name from an existing point tag value associated with the application point tag key, so you enter tagk, application as the source option parameter.
  • You want the new source name to be <value>_<appName>, so you specify period and hyphen as the "delimiterDefinition". You do not specify underscore (“_”) as a delimiter. If you were to do that, then the zeroBasedNodeIndex approach would no longer extract both the <value> and <appName> from the existing point tag value(s).
  • You set zeroBasedNodeIndex to 2. The delimiterDefinition choices – both hyphen and period – set <company> to 0, id to 1, and <value>_<appName> to 2.

The following set of examples uses the same scenarios as the zeroBasedNodeIndex examples, but uses the regular expression approach.

RegEx Example 1 - Renaming Source(s) with an Existing Source Name

For this example, you replace the zeroBasedNodeIndex in the example above with a regular expression:

aliasSource(ts(requests.failures.num), "app-([0-9]*)", "$1")
  • "regularExpression" is set to "app-([0-9]*)", so you capture everything after the app- substring that is a number and put that into capture group 1.
  • You can then refer to that capture group as $1 in the captureGroupBackReference.

RegEx Example 2 - Renaming Source(s) with a Metric Name

The syntax for implementing Example 2 using a regular expression is:

aliasSource(ts(*), metric, "disk.([a-z-0-9]*)..*", "$1")

RegEx Example 3 - Renaming Source(s) with a Point Tag Value

The syntax for implementing Example 3 using a regular expression is:

aliasSource(ts("application.latency"), tagk, application, ".*.id-(.*)", "$1")

RegEx Example 4 - Renaming Source(s) with a Source Name

The following example uses aliasSource() with a regular expression. For this example, using the regular expression is more straightforward.

Assume you have sources that look like this: accounts.<company_name>.<group name><numeric value>

You want to set the source to <company_name>.<group name> (i.e., leave off <numeric value>)

This table shows the current source and desired source names:

Current Source Desired Source

You can easily do this with aliasSource():

aliasSource(ts(requests.failures.num), "accounts.([a-zA-Z.]*)[0-9]*$", "$1")