Langfuse.Config (Langfuse v0.2.0)

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Configuration management for the Langfuse SDK.

The SDK reads configuration from application config and environment variables. Environment variables take precedence over application config.

Application Configuration

Configure Langfuse in your config/config.exs or runtime config:

config :langfuse,
  public_key: "pk-lf-...",
  secret_key: "sk-lf-...",
  host: "https://cloud.langfuse.com",
  environment: "production",
  flush_interval: 5_000,
  batch_size: 100,
  max_retries: 3,
  enabled: true

Environment Variables

These environment variables override application config:

  • LANGFUSE_PUBLIC_KEY - API public key
  • LANGFUSE_SECRET_KEY - API secret key
  • LANGFUSE_HOST - Langfuse server URL
  • LANGFUSE_ENVIRONMENT - Environment name (e.g., "production", "staging")
  • LANGFUSE_CACERTFILE - Path to a custom CA certificate PEM file

Configuration Options

  • :public_key - Langfuse API public key (required for API calls)
  • :secret_key - Langfuse API secret key (required for API calls)
  • :host - Langfuse server URL. Defaults to "https://cloud.langfuse.com".
  • :environment - Environment name for filtering in Langfuse dashboard. Common values: "production", "staging", "development".
  • :flush_interval - Interval in milliseconds between automatic flushes. Defaults to 5,000 (5 seconds).
  • :batch_size - Maximum events per batch before automatic flush. Defaults to 100.
  • :max_retries - Maximum retry attempts for failed requests. Defaults to 3.
  • :enabled - Whether tracing is enabled. Defaults to true. Set to false to disable all tracing (useful for tests).
  • :debug - Whether debug logging is enabled. Defaults to false. When enabled, logs detailed information about HTTP requests, batching, and event processing. Useful for troubleshooting integration issues.
  • :cacertfile - Path to a custom CA certificate PEM file for self-hosted Langfuse instances with self-signed certificates.

Self-Hosted Langfuse

For self-hosted Langfuse instances, set the host:

config :langfuse,
  host: "https://langfuse.mycompany.com",
  public_key: "pk-...",
  secret_key: "sk-...",
  cacertfile: "/etc/ssl/langfuse-root-ca.pem"

Summary

Types

t()

Configuration struct containing all SDK settings.

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

configured?()

Returns whether API credentials are configured.

debug?()

Returns whether debug logging is enabled.

enabled?()

Returns whether tracing is enabled.

get()

Returns the current configuration struct.

get(key)

Returns a specific configuration value by key.

reload()

Reloads configuration from application environment.

Types

t()

@type t() :: %Langfuse.Config{
  batch_size: pos_integer(),
  cacertfile: String.t() | nil,
  debug: boolean(),
  enabled: boolean(),
  environment: String.t() | nil,
  flush_interval: pos_integer(),
  host: String.t(),
  max_retries: non_neg_integer(),
  public_key: String.t() | nil,
  secret_key: String.t() | nil
}

Configuration struct containing all SDK settings.

The struct is populated on application start from application config and environment variables.

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

configured?()

@spec configured?() :: boolean()

Returns whether API credentials are configured.

Returns true if both :public_key and :secret_key are set.

Examples

Langfuse.Config.configured?()
# => true

debug?()

@spec debug?() :: boolean()

Returns whether debug logging is enabled.

When enabled, the SDK logs detailed information about HTTP requests, batching, and event processing to help troubleshoot integration issues.

Examples

Langfuse.Config.debug?()
# => false

enabled?()

@spec enabled?() :: boolean()

Returns whether tracing is enabled.

When disabled, all tracing operations become no-ops.

Examples

Langfuse.Config.enabled?()
# => true

get()

@spec get() :: t()

Returns the current configuration struct.

Examples

config = Langfuse.Config.get()
config.host
# => "https://cloud.langfuse.com"

get(key)

@spec get(atom()) :: term()

Returns a specific configuration value by key.

Examples

Langfuse.Config.get(:host)
# => "https://cloud.langfuse.com"

Langfuse.Config.get(:batch_size)
# => 100

reload()

@spec reload() :: :ok

Reloads configuration from application environment.

This is primarily useful for testing when you need to change configuration values at runtime.

Examples

Application.put_env(:langfuse, :host, "https://custom.langfuse.com")
Langfuse.Config.reload()