coder · johnstcn · Dec 19, 2023 · Dec 19, 2023 · Dec 19, 2023 · Dec 19, 2023
diff --git a/cli/clilog/clilog.go b/cli/clilog/clilog.go
@@ -0,0 +1,211 @@
+package clilog
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"regexp"
+	"strings"
+
+	"golang.org/x/xerrors"
+
+	"cdr.dev/slog"
+	"cdr.dev/slog/sloggers/sloghuman"
+	"cdr.dev/slog/sloggers/slogjson"
+	"cdr.dev/slog/sloggers/slogstackdriver"
+	"github.com/coder/coder/v2/cli/clibase"
+	"github.com/coder/coder/v2/coderd/tracing"
+	"github.com/coder/coder/v2/codersdk"
+)
+
+type (
+	Option  func(*Builder)
+	Builder struct {
+		Filter      []string
+		Human       string
+		JSON        string
+		Stackdriver string
+		Trace       bool
+		Verbose     bool
+	}
+)
+
+func New(opts ...Option) *Builder {
+	b := &Builder{}
+	for _, opt := range opts {
+		opt(b)
+	}
+	return b
+}
+
+func WithFilter(filters ...string) Option {
+	return func(b *Builder) {
+		b.Filter = filters
+	}
+}
+
+func WithHuman(loc string) Option {
+	return func(b *Builder) {
+		b.Human = loc
+	}
+}
+
+func WithJSON(loc string) Option {
+	return func(b *Builder) {
+		b.JSON = loc
+	}
+}
+
+func WithStackdriver(loc string) Option {
+	return func(b *Builder) {
+		b.Stackdriver = loc
+	}
+}
+
+func WithTrace() Option {
+	return func(b *Builder) {
+		b.Trace = true
+	}
+}
+
+func WithVerbose() Option {
+	return func(b *Builder) {
+		b.Verbose = true
+	}
+}
+
+func FromDeploymentValues(vals *codersdk.DeploymentValues) Option {
+	return func(b *Builder) {
+		b.Filter = vals.Logging.Filter.Value()
+		b.Human = vals.Logging.Human.Value()
+		b.JSON = vals.Logging.JSON.Value()
+		b.Stackdriver = vals.Logging.Stackdriver.Value()
+		b.Trace = vals.Trace.Enable.Value()
+		b.Verbose = vals.Verbose.Value()
+	}
+}
+
+func (b *Builder) Build(inv *clibase.Invocation) (log slog.Logger, closeLog func(), err error) {
+	var (
+		sinks   = []slog.Sink{}
+		closers = []func() error{}
+	)
+	defer func() {
+		if err != nil {
+			for _, closer := range closers {
+				_ = closer()
+			}
+		}
+	}()
+
+	noopClose := func() {}
+
+	addSinkIfProvided := func(sinkFn func(io.Writer) slog.Sink, loc string) error {
+		switch loc {
+		case "":
+
+		case "/dev/stdout":
+			sinks = append(sinks, sinkFn(inv.Stdout))
+
+		case "/dev/stderr":
+			sinks = append(sinks, sinkFn(inv.Stderr))
+
+		default:
+			fi, err := os.OpenFile(loc, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0o644)
+			if err != nil {
+				return xerrors.Errorf("open log file %q: %w", loc, err)
+			}
+			closers = append(closers, fi.Close)
+			sinks = append(sinks, sinkFn(fi))
+		}
+		return nil
+	}
+
+	err = addSinkIfProvided(sloghuman.Sink, b.Human)
+	if err != nil {
+		return slog.Logger{}, noopClose, xerrors.Errorf("add human sink: %w", err)
+	}
+	err = addSinkIfProvided(slogjson.Sink, b.JSON)
+	if err != nil {
+		return slog.Logger{}, noopClose, xerrors.Errorf("add json sink: %w", err)
+	}
+	err = addSinkIfProvided(slogstackdriver.Sink, b.Stackdriver)
+	if err != nil {
+		return slog.Logger{}, noopClose, xerrors.Errorf("add stackdriver sink: %w", err)
+	}
+
+	if b.Trace {
+		sinks = append(sinks, tracing.SlogSink{})
+	}
+
+	// User should log to null device if they don't want logs.
+	if len(sinks) == 0 {
+		return slog.Logger{}, noopClose, xerrors.New("no loggers provided, use /dev/null to disable logging")
+	}
+
+	filter := &debugFilterSink{next: sinks}
+
+	err = filter.compile(b.Filter)
+	if err != nil {
+		return slog.Logger{}, noopClose, xerrors.Errorf("compile filters: %w", err)
+	}
+
+	level := slog.LevelInfo
+	// Debug logging is always enabled if a filter is present.
+	if b.Verbose || filter.re != nil {
+		level = slog.LevelDebug
+	}
+
+	return inv.Logger.AppendSinks(filter).Leveled(level), func() {
+		for _, closer := range closers {
+			_ = closer()
+		}
+	}, nil
+}
+
+var _ slog.Sink = &debugFilterSink{}
+
+type debugFilterSink struct {
+	next []slog.Sink
+	re   *regexp.Regexp
+}
+
+func (f *debugFilterSink) compile(res []string) error {
+	if len(res) == 0 {
+		return nil
+	}
+
+	var reb strings.Builder
+	for i, re := range res {
+		_, _ = fmt.Fprintf(&reb, "(%s)", re)
+		if i != len(res)-1 {
+			_, _ = reb.WriteRune('|')
+		}
+	}
+
+	re, err := regexp.Compile(reb.String())
+	if err != nil {
+		return xerrors.Errorf("compile regex: %w", err)
+	}
+	f.re = re
+	return nil
+}
+
+func (f *debugFilterSink) LogEntry(ctx context.Context, ent slog.SinkEntry) {
+	if ent.Level == slog.LevelDebug {
+		logName := strings.Join(ent.LoggerNames, ".")
+		if f.re != nil && !f.re.MatchString(logName) && !f.re.MatchString(ent.Message) {
+			return
+		}
+	}
+	for _, sink := range f.next {
+		sink.LogEntry(ctx, ent)
+	}
+}
+
+func (f *debugFilterSink) Sync() {
+	for _, sink := range f.next {
+		sink.Sync()
+	}
+}