# Operations & Functions Reference > Complete reference for all Uptrace transformation operation types and built-in Expr functions for spans, logs, events, and metric datapoints. Complete reference for all transformation operation types and built-in functions. See [Introduction](/features/transformations) for an overview, scope rules, and common recipes. ## Operations ### Rename attribute ```yaml name: Rename service to service_name scope: [spans, logs, events] type: rename_attr old_key: service new_key: service_name ``` Set `overwrite: true` to overwrite the target attribute if it already exists: ```yaml name: Rename service to service_name scope: [spans, logs, events] type: rename_attr old_key: service new_key: service_name overwrite: true ``` ### Delete attributes By key list: ```yaml name: Delete foo and bar scope: [spans, logs, events, datapoints] type: delete_attrs keys: - foo - bar ``` By regular expression: ```yaml name: Delete foo and bar scope: [spans, logs, events, datapoints] type: delete_attrs regexp: ^(foo|bar)$ ``` Scoped to a specific metric: ```yaml name: Delete foo and bar from my_metric scope: [datapoints] type: delete_attrs keys: - foo - bar if: metricName() == "my_metric_name" ``` ### Keep attributes ```yaml name: Keep foo and bar scope: [spans, logs, events, datapoints] type: keep_attrs keys: - foo - bar ``` By regular expression: ```yaml name: Keep foo and bar scope: [spans, logs, events, datapoints] type: keep_attrs regexp: ^(foo|bar)$ ``` ### Drop ```yaml name: Drop hello logs scope: [logs] type: drop if: attr("log_message") contains "hello" ``` ```yaml name: Drop Redis evalsha scope: [spans] type: drop if: spanName() == "evalsha" && spanStatusCode() != "error" ``` The `if` condition is required for `drop`. Execution stops for the matching record — subsequent operations are skipped. ### Sample ```yaml name: Sample 50% hello logs scope: [logs] type: sample fraction: 0.5 if: attr("log_message") startsWith "hello" ``` `fraction` must be between 0 and 1. For spans, sampling is trace-aware: all spans in a trace are kept or dropped together. The `if` condition is optional — omitting it applies sampling to all records in scope. ### Change attribute type ```yaml name: Convert elapsed_ms to float scope: [spans] type: change_attr_type key: elapsed_ms type: float ``` Supported types: `string`, `int`, `float`, `bool`. `change_attr_type` is not supported for datapoints. Use the `script` operation with type parsing functions instead. ### Flatten map By default, Uptrace does not index attributes that contain nested maps. The `flatten_map` operation extracts dot-separated paths from a map attribute so they can be queried: ```yaml name: Flatten the object attribute scope: [spans] type: flatten_map maps: ['object'] include_paths: ['object.nested.foo'] include_regexp: '^object.nested\.' exclude_paths: ['object.nested.hello'] exclude_regexp: 'secret' ``` Without `include_paths` or `include_regexp`, the entire map is indexed up to 32 paths. ### IP geo attributes Enriches IP address attributes with GeoIP data. For each specified key, Uptrace adds `{key}_country_code`, `{key}_country_name`, and `{key}_city`: ```yaml name: Enrich custom IP with geo data scope: [spans, logs, events] type: ip_geo_attrs keys: - custom_ip_address ``` `client_address` and `client_socket_address` are automatically processed by Uptrace and should not be added manually. `ip_geo_attrs` is not supported for datapoints. ### Text index Builds a full-text index column from selected attribute values, enabling `*:value` [search syntax](/features/searching#searching-indexed-content): ```yaml name: Index request attributes scope: [spans, logs, events] type: text_index include: - log_message - exception_message - http.request.** exclude: - http.request.headers.** ``` The `include` field accepts glob patterns:

Pattern	Description
`foo`	Indexes the `foo` attribute directly
`foo.**`	Indexes all nested keys in the `foo` map
`foo.*`	Indexes one level of nested keys
`foo?.bar`	Matches `foo1` , `foo2` , etc.

Search is case-insensitive and token-based (no substring matching). Maximum indexed text per record: 4096 bytes. Text Index is billed separately based on indexed bytes. See the pricing page for details. ### Script Write arbitrary expressions to modify telemetry. The `if` condition is required. Set error status when exception attributes are present: ```yaml name: Set error status when exception attributes are present scope: [spans] type: script if: hasAttr("exception_type") && hasAttr("exception_message") then: - setSpanStatusCode("error") - setSpanStatusMessage(attr("exception_message")) else: - setSpanStatusCode("ok") ``` Parse a string attribute as float: ```yaml name: Parse elapsed_ms scope: [spans] type: script if: hasAttr("elapsed_ms") then: - setAttr("elapsed_ms", parseFloat(attr("elapsed_ms"))) ``` Reduce attribute cardinality: ```yaml name: Normalize http_target scope: [spans] type: script if: metricName() startsWith "http_server_" && hasAttr("http_target") then: - setAttr("http_target", replaceGlob(attr("http_target"), "/user/*/list/*", "/user/{userId}/list/{listId}")) ``` Replace all numbers using a regular expression: ```yaml name: Replace numbers in foo scope: [spans] type: script if: hasAttr("foo") then: - setAttr("foo", replaceAllRegexp(attr("foo"), "(\\d+)", "")) ``` Convert a log into a span: ```yaml name: Convert logs with elapsed_ms to spans scope: [logs] type: script if: hasAttr("elapsed_ms") then: - setSpanName("operation-name") - setLogName("") - setSpanDuration(parseFloat(attr("elapsed_ms")) * 1e6) - setSpanStatusCode("ok") ``` --- ## Functions reference In addition to built-in [Expr](https://expr-lang.org/docs/language-definition) functions, Uptrace provides the following. All functions work in both `if` conditions and `script` expressions. ### Span, log, and event functions #### Getters

Function	Scope	Description
`spanName()`	spans, logs, events	Returns the span name or an empty string.
`eventName()`	events	Returns the event name or an empty string.
`logName()`	logs	Returns the log name (alias for `eventName` ).
`spanKind()`	spans	Returns the span kind (`internal` , `server` , `client` , `producer` , `consumer` ).
`spanDuration()`	spans	Returns the span duration as a `time.Duration` (nanosecond precision).
`spanStatusCode()`	spans, logs, events	Returns the span status code (`unset` , `ok` , `error` ).
`spanStatusMessage()`	spans, logs, events	Returns the span status message.

#### Setters

Function	Scope	Description
`setSpanName(string)`	spans	Sets the span name.
`setEventName(string)`	events	Sets the event name.
`setLogName(string)`	logs	Sets the log name.
`setSpanKind(string)`	spans	Sets the span kind. Must be one of: `internal` , `server` , `client` , `producer` , `consumer` .
`setSpanDuration(nanoseconds)`	spans	Sets the span duration in nanoseconds. Accepts `int` , `int64` , or `time.Duration` .
`setSpanStatusCode(string)`	spans	Sets the span status code (`unset` , `ok` , `error` ).
`setSpanStatusMessage(string)`	spans	Sets the span status message.

#### Attribute functions

Function	Scope	Description
`attr(key)`	spans, logs, events	Returns the attribute value by key.
`attrType(key)`	spans, logs, events	Returns the type: `nil` , `string` , `int` , `float` , `bool` , `array` , or `map` .
`hasAttr(key)`	spans, logs, events	Returns `true` if the attribute exists.
`setAttr(key, value)`	spans, logs, events	Sets the attribute value.
`deleteAttr(key)`	spans, logs, events	Deletes the attribute.
`renameAttr(oldKey, newKey)`	spans, logs, events	Renames the attribute.
`renameAttr(oldKey, newKey, overwrite)`	spans, logs, events	Renames the attribute, optionally overwriting if the target exists.

#### Type parsing functions

Function	Scope	Description
`parseInt(value)`	spans, logs, events	Parses the value as `int64` .
`parseUint(value)`	spans, logs, events	Parses the value as `uint64` .
`parseFloat(value)`	spans, logs, events	Parses the value as `float64` .
`parseBool(value)`	spans, logs, events	Parses as `bool` . Accepts `"true"` , `"false"` , `"1"` , `"0"` .

### Datapoint functions #### Getters

Function	Description
`metricName()`	Returns the metric name.
`metricUnit()`	Returns the metric unit.
`metricInstrument()`	Returns the metric instrument type.
`libraryName()`	Returns the instrumentation library name.
`libraryVersion()`	Returns the instrumentation library version.

#### Setters

Function	Description
`setMetricName(string)`	Sets the metric name.
`setMetricUnit(string)`	Sets the metric unit.
`setMetricInstrument(string)`	Sets the metric instrument type.

#### Attribute functions

Function	Description
`attr(key)`	Returns the attribute value as a string.
`hasAttr(key)`	Returns `true` if the attribute exists.
`setAttr(key, value)`	Sets the attribute value.
`deleteAttr(key)`	Deletes the attribute.
`renameAttr(oldKey, newKey)`	Renames the attribute.
`renameAttr(oldKey, newKey, overwrite)`	Renames the attribute, optionally overwriting.

### Common functions

Function	Description
`replaceGlob(src, pattern, repl)`	Returns `repl` if `src` matches glob `pattern` , otherwise returns `src` .
`replaceAllRegexp(src, pattern, repl)`	Replaces all regexp matches in `src` with `repl` .
`extractAllRegexp(src, pattern, repl)`	Extracts and transforms all regexp matches from `src` using `repl` template.
`parseDuration(string)`	Parses a duration string (e.g. `"1h30m"` , `"500ms"` ) as `time.Duration` .
`parseByteSize(string)`	Parses a byte size string (e.g. `"1GB"` , `"512MB"` ) as `int64` bytes.

## Related - [Expr language definition](https://expr-lang.org/docs/language-definition) - [Introduction](/features/transformations) — overview, scope rules, and common recipes