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core/org.llm4s/org.llm4s.trace/LangfuseTracing

LangfuseTracing

org.llm4s.trace.LangfuseTracing
See theLangfuseTracing companion object
class LangfuseTracing(langfuseUrl: String, publicKey: String, secretKey: String, environment: String, release: String, version: String) extends Tracing

Langfuse Tracing implementation for production observability.

Sends trace events to Langfuse for centralized observability, debugging, and LLM application monitoring. Supports all trace event types with type-safe Result[Unit] return values.

== Features ==

  • Real-time event streaming to Langfuse
  • Hierarchical trace structure (traces with child spans)
  • Token usage and cost tracking
  • Error logging with stack traces
  • Agent state snapshots with conversation history

== Configuration ==

Configure via environment variables or direct instantiation:

// Environment variables
LANGFUSE_PUBLIC_KEY=pk-lf-...
LANGFUSE_SECRET_KEY=sk-lf-...
LANGFUSE_URL=https://cloud.langfuse.com (optional)

// Or programmatic configuration
val tracing = new LangfuseTracing(
 langfuseUrl = "https://cloud.langfuse.com",
 publicKey = "pk-lf-...",
 secretKey = "sk-lf-...",
 environment = "production",
 release = "1.0.0",
 version = "1.0.0"
)

== Usage ==

val tracing: Tracing = LangfuseTracing.from(config)

for {
 _ <- tracing.traceEvent(TraceEvent.AgentInitialized("query", tools))
 _ <- tracing.traceCompletion(completion, "gpt-4")
 _ <- tracing.traceTokenUsage(usage, "gpt-4", "completion")
} yield ()

Value parameters

environment

Environment name (e.g., "production", "staging")

langfuseUrl

Langfuse API URL (default: https://cloud.langfuse.com)

publicKey

Langfuse public key for authentication

release

Release/version identifier

secretKey

Langfuse secret key for authentication

version

API version

Attributes

See also

ConsoleTracing for local development

NoOpTracing for disabled tracing

TracingMode for configuration modes

Companion
object
Graph
Supertypes
trait Tracing
class Object
trait Matchable
class Any

Members list

Value members

Concrete methods

def traceAgentState(state: AgentState): Result[Unit]
def traceCompletion(completion: Completion, model: String): Result[Unit]
def traceError(error: Throwable, context: String): Result[Unit]
def traceEvent(event: TraceEvent): Result[Unit]
def traceTokenUsage(usage: TokenUsage, model: String, operation: String): Result[Unit]
def traceToolCall(toolName: String, input: String, output: String): Result[Unit]

Inherited methods

final def traceCost(costUsd: Double, model: String, operation: String, tokenCount: Int, costType: String): Result[Unit]

Trace cost in USD for any operation.

Trace cost in USD for any operation.

Value parameters

costType

Category: "embedding", "completion", "total"

costUsd

Cost in US dollars

model

Model name

operation

Type: "embedding", "completion", "evaluation"

tokenCount

Total tokens used

Attributes

Inherited from:
Tracing
final def traceEmbeddingUsage(usage: EmbeddingUsage, model: String, operation: String, inputCount: Int): Result[Unit]

Trace embedding token usage for cost tracking.

Trace embedding token usage for cost tracking.

Value parameters

inputCount

Number of texts embedded

model

Embedding model name

operation

Type: "indexing", "query", "evaluation"

usage

Token usage from embedding operation

Attributes

Inherited from:
Tracing
final def traceEvent(event: String): Result[Unit]

Attributes

Inherited from:
Tracing
final def traceRAGOperation(operation: String, durationMs: Long, embeddingTokens: Option[Int], llmPromptTokens: Option[Int], llmCompletionTokens: Option[Int], totalCostUsd: Option[Double]): Result[Unit]

Trace completion of a RAG operation with metrics.

Trace completion of a RAG operation with metrics.

Value parameters

durationMs

Duration in milliseconds

embeddingTokens

Optional embedding token count

llmCompletionTokens

Optional LLM completion tokens

llmPromptTokens

Optional LLM prompt tokens

operation

Type: "index", "search", "answer", "evaluate"

totalCostUsd

Optional total cost in USD

Attributes

Inherited from:
Tracing
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