vojo/apps/ai-bot/logging.go

115 lines
4.3 KiB
Go

package main
import (
"context"
"log/slog"
"os"
"strings"
)
// newLogger builds the process logger from the environment: LOG_LEVEL
// (debug|info|warn|error, default info) and LOG_FORMAT (text|json, default
// text). It writes to stderr with UTC timestamps (matching the previous
// log.LUTC behaviour). Built from getenv directly — not Config — so it exists
// before LoadConfig (the generate-registration path logs before config loads).
func newLogger() *slog.Logger {
opts := &slog.HandlerOptions{
Level: parseLogLevel(getenv("LOG_LEVEL", "info")),
ReplaceAttr: func(_ []string, a slog.Attr) slog.Attr {
if a.Key == slog.TimeKey && a.Value.Kind() == slog.KindTime {
a.Value = slog.TimeValue(a.Value.Time().UTC())
}
return a
},
}
var h slog.Handler
if strings.EqualFold(strings.TrimSpace(getenv("LOG_FORMAT", "text")), "json") {
h = slog.NewJSONHandler(os.Stderr, opts)
} else {
h = slog.NewTextHandler(os.Stderr, opts)
}
// Wrap so every record logged with a *Context method carries the request trace_id.
return slog.New(contextHandler{h})
}
// contextHandler wraps a slog.Handler so a record logged with one of the *Context methods
// (InfoContext/DebugContext/WarnContext/ErrorContext) automatically gets the request's
// trace_id attached — the userver-style trail, set once at the top of a request and
// carried through to the model call. Records logged without a traced context (startup,
// the appservice transaction handler) simply carry no trace_id. The field is named
// trace_id (the OTel convention) so it maps cleanly into OpenSearch and a future OTel
// exporter.
type contextHandler struct{ slog.Handler }
func (h contextHandler) Handle(ctx context.Context, r slog.Record) error {
if id := traceFromContext(ctx); id != "" {
r.AddAttrs(slog.String("trace_id", id))
}
return h.Handler.Handle(ctx, r)
}
// WithAttrs/WithGroup must re-wrap, or the embedded handler's versions would return a
// bare handler and silently drop the trace_id injection for any child logger.
func (h contextHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
return contextHandler{h.Handler.WithAttrs(attrs)}
}
func (h contextHandler) WithGroup(name string) slog.Handler {
return contextHandler{h.Handler.WithGroup(name)}
}
// logLLMExchange logs the raw request/response bodies of one model call at DEBUG, but
// ONLY for senders on the LOG_BODIES_USERS allowlist (the per-request `verbose` flag
// stamped into ctx at admission). Everyone else gets routing + metadata logs only, so
// message content never enters the logs unless an operator opts a specific user in AND
// runs at LOG_LEVEL=debug (DebugContext is suppressed otherwise). Only the request and
// response BODIES are logged — never the URL or any header — so the API key cannot leak
// whether it rides in the Authorization header (xAI / Gemini-compat) or the URL query
// string (Gemini native grounding). Bodies are truncated to llmBodyLogMax bytes, and the
// auto-injected trace_id ties the exchange to the rest of the request's lines.
func logLLMExchange(ctx context.Context, log *slog.Logger, provider string, reqBody []byte, status int, respBody []byte) {
if log == nil {
return
}
ri, ok := reqInfoFromContext(ctx)
if !ok || !ri.verbose {
return
}
log.DebugContext(ctx, "llm exchange",
"provider", provider,
"sender", ri.sender,
"status", status,
"request", truncateForLog(reqBody, llmBodyLogMax),
"response", truncateForLog(respBody, llmBodyLogMax),
)
}
// llmBodyLogMax caps each logged model body. A fixed constant, not an env knob — the cap
// only bounds log volume on an opt-in debug path and never needs per-deploy tuning. ~4 KB
// keeps a typical prompt/answer readable while staying bounded.
const llmBodyLogMax = 4096
// truncateForLog renders a body for a log line, capped at maxBytes (≤0 → a 2000-byte
// default) with an ellipsis marker so a truncated payload is visibly truncated.
func truncateForLog(b []byte, maxBytes int) string {
if maxBytes <= 0 {
maxBytes = 2000
}
if len(b) > maxBytes {
return string(b[:maxBytes]) + "…(truncated)"
}
return string(b)
}
func parseLogLevel(s string) slog.Level {
switch strings.ToLower(strings.TrimSpace(s)) {
case "debug":
return slog.LevelDebug
case "warn", "warning":
return slog.LevelWarn
case "error":
return slog.LevelError
default:
return slog.LevelInfo
}
}