Search specification

Overview

This topic explains how to use LaunchDarkly’s observability search feature to query and filter data across your application. The search functionality allows you to find specific sessions, errors, logs, and traces by composing queries with different properties and attributes.

Compose search queries

Compose your search query with one or more expressions. Each expression can be a comparison between a key and a value, or a logical combination of other expressions.

Here are some examples of search queries:

span_name=gorm.Query

Find sessions associated with a specific feature flag.

events.attributes.feature_flag.key=EXAMPLE_FLAG_KEY

Enter a search value without a key to search on a default key. For logs, the default key is the message, and for traces it is the span_name.

gorm.Query

You can also filter for custom attributes you send in sessions, logs, and traces.

user_id=42

Keys and values

Keys are identifiers, which can include any combination of alphanumeric characters, underscores (_), periods (.), dashes (-), and wildcards, which are indicated by asterisks (*).

Values are strings with any character. To use spaces or special characters, you must enclose the string in quotes (", ').

You can use wildcards (*) in values to match on part of a pattern. For example:

• span_name=gorm.* matches all span_name values that start with gorm.
• span_name=*.Query matches all span_name values that end with .Query
• span_name=*orm* matches all values that contain orm

If you want to use a value with a space or special character, you must wrap the value in quotations.

tag="*query error*"
visited-url="https://app.launchdarkly.com/*"

Regex expressions

You can search with regex expressions by using the matches query operator: =/[your regex here]/. For example:

• clickTextContent=/\w.+\w/ matches all clickTextContent that start and end with any word
• browser_version=/\d\.\d\.\d/ matches all browser_version values in the form [0-9].[0-9].[0-9]

If you want to use a regex expression with a space or special character, you must wrap the value in quotations. For example:

• tag="/\w \w/"
• visited-url="/https://app.launchdarkly.com/\d/.+/"

Comparisons

Use operators to compare two different elements in your search query. The following operators are supported:

• =: Equals
• !=: Does not equal
• <: Less than
• <=: Less than or equal to
• >: Greater than
• >=: Greater than or equal to

Exist and does not exist

You can search if a key exists or does not exist with the exists operator. For example, to return all the traces with a connected session, use the following query:

secure_session_id exists

exists also works with the not keyword. For example, when you only want the root level spans when searching traces, use this query:

parent_span_id not exists

You can combine expressions with the logical operators AND, OR, and NOT:

• AND: Both expressions must be true
• OR: At least one of the expressions must be true
• NOT: The following expression must be false

Filters are combined with an implicit AND unless you specify OR. For example:

service_name=private-graph span_name=gorm.Query

This is equivalent to:

service_name=private-graph AND span_name=gorm.Query

You can also use parentheses ( AND ) to group values in an expression. For example:

(key1=value1 AND key2=value2) OR key3=value3

You can also use parentheses to group values in an expression:

service_name=(private-graph OR public-graph)

Span functions for trace search

The search functionality on the Traces page returns individual spans that make up traces.

Span functions help you filter results to show only those spans for traces that contain or don’t contain spans that match one or more conditions.

The following span functions are available when you search on the Traces page:

• any_span( expression ) limits results to spans where the trace contains at least one span that matches the expression.
• any_span2() and any_span3() operate in the same way as any_span(). The unique function names let you require different spans in the trace to satisfy different conditions in the same query. To learn more, read Using multiple span aliases.
• no_span( expression ) limits results to spans where the trace contains no spans that match the inner expression.

Span functions wrap a normal search expression in parentheses. Inside the parentheses, you can use any of the existing operators, including comparisons, EXISTS, AND, OR, and NOT.

Here is an example that returns spans whose trace contains at least one span from the auth-service:

any_span(service_name=auth-service)

Here is an example that returns spans whose trace contains at least one error in an auth-service span:

any_span(service_name=auth-service AND has_errors=true)

Here is an example that returns spans whose trace contains no spans with errors:

no_span(has_errors=true)

Using multiple span aliases

If you call any_span() more than once in a query, the conditions accumulate against the same span. For example, this query requires a single span in the trace to match both conditions:

any_span(service_name=checkout) any_span(has_errors=true)

To require that different spans in the trace satisfy each condition, use any_span2() or any_span3() for the second condition. Here is an example that returns spans whose trace contains at least one checkout span and another, different span that contains errors:

any_span(service_name=checkout) any_span2(has_errors=true)

Combining span functions with regular search expressions

You can combine span functions with regular search expressions in the same query. Regular expressions filter the displayed spans by their own properties, while span functions filter the displayed spans by conditions that apply to the same trace. Here is an example:

environment=production any_span(service_name=auth-service AND duration>1s)

This query returns spans in the production environment whose trace also contains at least one auth-service span that lasts longer than one second.

Limitations

You can only use span functions as top-level filters in a query.

Span functions have the following restrictions:

• You cannot wrap span functions in parentheses.
• All span functions at the top level of a query are joined with an implicit AND operator. You cannot combine span functions using AND, OR, or NOT outside of the function call.

These restrictions apply to the span function itself. Inside the parentheses, the inner expression supports the full set of search operators, including AND, OR, NOT, EXISTS, and grouping.

Saved searches

Saved searches are a set of search filters that apply to sessions or errors. Saved searches are useful if you want to quickly view sessions or errors that relate to a certain population of your end users.

To save a search, click the Save button below the search bar.

The searches you build are reflected in the URL parameters when you’re accessing sessions through the LaunchDarkly UI. You can share these URLs with others to deep link to search results, or create them programmatically.

Session-specific searching

To learn more about search terms and defaults specific to session replays, read Search in the Session replay topic.

Configure error views

You can configure the Errors page to display different subsets of errors. Use the date dropdown to select a time range, and search in the search bar to filter the errors.