[log] tracing loggerpull/1842/head
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package log | |||
import ( | |||
"fmt" | |||
"github.com/pkg/errors" | |||
) | |||
// NewTracingLogger enables tracing by wrapping all errors (if they | |||
// implement stackTracer interface) in tracedError. | |||
// | |||
// All errors returned by https://github.com/pkg/errors implement stackTracer | |||
// interface. | |||
// | |||
// For debugging purposes only as it doubles the amount of allocations. | |||
func NewTracingLogger(next Logger) Logger { | |||
return &tracingLogger{ | |||
next: next, | |||
} | |||
} | |||
type stackTracer interface { | |||
error | |||
StackTrace() errors.StackTrace | |||
} | |||
type tracingLogger struct { | |||
next Logger | |||
} | |||
func (l *tracingLogger) Info(msg string, keyvals ...interface{}) error { | |||
return l.next.Info(msg, formatErrors(keyvals)...) | |||
} | |||
func (l *tracingLogger) Debug(msg string, keyvals ...interface{}) error { | |||
return l.next.Debug(msg, formatErrors(keyvals)...) | |||
} | |||
func (l *tracingLogger) Error(msg string, keyvals ...interface{}) error { | |||
return l.next.Error(msg, formatErrors(keyvals)...) | |||
} | |||
func (l *tracingLogger) With(keyvals ...interface{}) Logger { | |||
return &tracingLogger{next: l.next.With(formatErrors(keyvals)...)} | |||
} | |||
func formatErrors(keyvals []interface{}) []interface{} { | |||
newKeyvals := make([]interface{}, len(keyvals)) | |||
copy(newKeyvals, keyvals) | |||
for i := 0; i < len(newKeyvals)-1; i += 2 { | |||
if err, ok := newKeyvals[i+1].(stackTracer); ok { | |||
newKeyvals[i+1] = tracedError{err} | |||
} | |||
} | |||
return newKeyvals | |||
} | |||
// tracedError wraps a stackTracer and just makes the Error() result | |||
// always return a full stack trace. | |||
type tracedError struct { | |||
wrapped stackTracer | |||
} | |||
var _ stackTracer = tracedError{} | |||
func (t tracedError) StackTrace() errors.StackTrace { | |||
return t.wrapped.StackTrace() | |||
} | |||
func (t tracedError) Cause() error { | |||
return t.wrapped | |||
} | |||
func (t tracedError) Error() string { | |||
return fmt.Sprintf("%+v", t.wrapped) | |||
} |
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package log_test | |||
import ( | |||
"bytes" | |||
stderr "errors" | |||
"fmt" | |||
"strings" | |||
"testing" | |||
"github.com/pkg/errors" | |||
"github.com/tendermint/tmlibs/log" | |||
) | |||
func TestTracingLogger(t *testing.T) { | |||
var buf bytes.Buffer | |||
var logger log.Logger | |||
logger = log.NewTMJSONLogger(&buf) | |||
logger1 := log.NewTracingLogger(logger) | |||
err1 := errors.New("Courage is grace under pressure.") | |||
err2 := errors.New("It does not matter how slowly you go, so long as you do not stop.") | |||
logger1.With("err1", err1).Info("foo", "err2", err2) | |||
have := strings.Replace(strings.Replace(strings.TrimSpace(buf.String()), "\\n", "", -1), "\\t", "", -1) | |||
if want := strings.Replace(strings.Replace(`{"_msg":"foo","err1":"`+fmt.Sprintf("%+v", err1)+`","err2":"`+fmt.Sprintf("%+v", err2)+`","level":"info"}`, "\t", "", -1), "\n", "", -1); want != have { | |||
t.Errorf("\nwant '%s'\nhave '%s'", want, have) | |||
} | |||
buf.Reset() | |||
logger.With("err1", stderr.New("Opportunities don't happen. You create them.")).Info("foo", "err2", stderr.New("Once you choose hope, anything's possible.")) | |||
if want, have := `{"_msg":"foo","err1":"Opportunities don't happen. You create them.","err2":"Once you choose hope, anything's possible.","level":"info"}`, strings.TrimSpace(buf.String()); want != have { | |||
t.Errorf("\nwant '%s'\nhave '%s'", want, have) | |||
} | |||
buf.Reset() | |||
logger.With("user", "Sam").With("context", "value").Info("foo", "bar", "baz") | |||
if want, have := `{"_msg":"foo","bar":"baz","context":"value","level":"info","user":"Sam"}`, strings.TrimSpace(buf.String()); want != have { | |||
t.Errorf("\nwant '%s'\nhave '%s'", want, have) | |||
} | |||
} |