// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0
/*
Package logger provides context-scoped structured logging for Genkit.
This package wraps the standard library's [log/slog] package to provide
context-aware logging throughout Genkit operations. Logs are automatically
associated with the current action or flow context.
# Usage
Retrieve the logger from context within action or flow handlers:
func myFlow(ctx context.Context, input string) (string, error) {
log := logger.FromContext(ctx)
log.Info("Processing input", "size", len(input))
log.Debug("Input details", "value", input)
result, err := process(input)
if err != nil {
log.Error("Processing failed", "error", err)
return "", err
}
log.Info("Processing complete", "resultSize", len(result))
return result, nil
}
# Log Levels
Control the global log level to filter output:
// Show debug logs (verbose)
logger.SetLevel(slog.LevelDebug)
// Show info and above (default)
logger.SetLevel(slog.LevelInfo)
// Show only warnings and errors
logger.SetLevel(slog.LevelWarn)
// Show only errors
logger.SetLevel(slog.LevelError)
// Get the current log level
level := logger.GetLevel()
# Context Integration
The logger is automatically available in action and flow contexts. It
inherits from the context passed to [genkit.Init] and flows through
all nested operations.
For custom operations outside of actions/flows, attach a logger to context:
log := slog.Default()
ctx = logger.WithContext(ctx, log)
# slog Compatibility
The logger returned by [FromContext] is a standard [*slog.Logger] and
supports all slog methods:
log := logger.FromContext(ctx)
// Structured logging with attributes
log.Info("User action",
"userId", userID,
"action", "login",
"duration", elapsed,
)
// Grouped attributes
log.Info("Request completed",
slog.Group("request",
"method", r.Method,
"path", r.URL.Path,
),
slog.Group("response",
"status", status,
"bytes", written,
),
)
// With pre-set attributes
requestLog := log.With("requestId", requestID)
requestLog.Info("Starting")
// ... later ...
requestLog.Info("Finished")
This package is primarily used by Genkit internals but is useful for
plugin developers who need consistent logging that integrates with
Genkit's observability features.
*/
package logger
