Golem Logging Scala

Logging from a Scala Agent

The Scala SDK provides golem.wasi.Logging — a typed facade over wasi:logging/logging with convenience methods for each log level and an optional context parameter.

Quick Start

Import and use the Logging object directly — no initialization needed:

import golem.wasi.Logging

Logging.info("order created: " + orderId)
Logging.debug("processing item: " + itemId)
Logging.warn("retry attempt " + attempt + " for request " + reqId)
Logging.error("failed to connect: " + err.getMessage)

Log Levels

Context Strings

Every method accepts an optional context parameter (defaults to ""). Use it to scope log entries to a subsystem or request:

Logging.info("connected to database", context = "db")
Logging.debug(s"query took ${ms}ms", context = "db/query")
Logging.error(s"timeout after ${retries} retries", context = "http-client")

For the lowest-level API, call Logging.log directly:

Logging.log(Logging.Level.Critical, "shutdown", "system is shutting down")

Using println / System.err.println

Standard output and error also work and are captured by Golem:

println("stdout message")
System.err.println("stderr message")

These appear in golem agent stream output but lack log levels and context. Prefer Logging.* methods for structured, filterable logging.

Viewing Logs

Stream live agent output:

golem agent stream '<agent-id>'

Or during an invocation:

golem agent invoke '<agent-id>' '<method>' [args]

Key Points

• No setup needed — golem.wasi.Logging is available from golem-scala-core which is already in the project dependencies
• All methods map directly to the wasi:logging/logging WASI interface
• Context strings help group and filter log entries by subsystem
• Logs are recorded in the oplog and visible via golem agent stream and golem agent invoke
• Logging is a side effect — during replay (crash recovery), log calls from replayed operations are skipped