Fix duplicated tags in InfluxDB

Gopkg.lock

@@ -569,8 +569,8 @@
     "metrics/statsd",
     "util/conn"
   ]
-  revision = "f66b0e13579bfc5a48b9e2a94b1209c107ea1f41"
-  version = "v0.3.0"
+  revision = "ca4112baa34cb55091301bdc13b1420a122b1b9e"
+  version = "v0.7.0"
 
 [[projects]]
   name = "github.com/go-logfmt/logfmt"
@@ -761,6 +761,7 @@
   version = "v1.3.7"
 
 [[projects]]
+  branch = "master"
   name = "github.com/jjcollinge/servicefabric"
   packages = ["."]
   revision = "8eebe170fa1ba25d3dfb928b3f86a7313b13b9fe"
@@ -1674,6 +1675,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "ffd938a3cb26d3d0926b34a98708af0a3db49311e03edc91649ea1baad1b97e9"
+  inputs-digest = "3142954e49f77ea41aea160bb9b57c0281c31f6de6652bbf3ec98ea3bc8fc494"
   solver-name = "gps-cdcl"
   solver-version = 1

Gopkg.toml

@@ -97,7 +97,7 @@
 
 [[constraint]]
   name = "github.com/go-kit/kit"
-  version = "0.3.0"
+  version = "0.7.0"
 
 [[constraint]]
   branch = "master"

metrics/influxdb_test.go

@@ -24,21 +24,21 @@ func TestInfluxDB(t *testing.T) {
 	}
 
 	expectedBackend := []string{
-		`(traefik\.backend\.requests\.total,code=200,method=GET,service=test count=1) [\d]{19}`,
-		`(traefik\.backend\.requests\.total,code=404,method=GET,service=test count=1) [\d]{19}`,
-		`(traefik\.backend\.request\.duration(?:,backend=test)?,code=200,method=GET,service=test(?:,url=http://127.0.0.1)? p50=10000,p90=10000,p95=10000,p99=10000) [\d]{19}`,
-		`(traefik\.backend\.retries\.total(?:,code=[\d]{3},method=GET)?,service=test count=2) [\d]{19}`,
+		`(traefik\.backend\.requests\.total,backend=test,code=200,method=GET count=1) [\d]{19}`,
+		`(traefik\.backend\.requests\.total,backend=test,code=404,method=GET count=1) [\d]{19}`,
+		`(traefik\.backend\.request\.duration,backend=test,code=200 p50=10000,p90=10000,p95=10000,p99=10000) [\d]{19}`,
+		`(traefik\.backend\.retries\.total(?:,code=[\d]{3},method=GET)?,backend=test count=2) [\d]{19}`,
 		`(traefik\.config\.reload\.total(?:[a-z=0-9A-Z,]+)? count=1) [\d]{19}`,
 		`(traefik\.config\.reload\.total\.failure(?:[a-z=0-9A-Z,]+)? count=1) [\d]{19}`,
 		`(traefik\.backend\.server\.up,backend=test(?:[a-z=0-9A-Z,]+)?,url=http://127.0.0.1 value=1) [\d]{19}`,
 	}
 
 	msgBackend := udp.ReceiveString(t, func() {
-		influxDBRegistry.BackendReqsCounter().With("service", "test", "code", strconv.Itoa(http.StatusOK), "method", http.MethodGet).Add(1)
-		influxDBRegistry.BackendReqsCounter().With("service", "test", "code", strconv.Itoa(http.StatusNotFound), "method", http.MethodGet).Add(1)
-		influxDBRegistry.BackendRetriesCounter().With("service", "test").Add(1)
-		influxDBRegistry.BackendRetriesCounter().With("service", "test").Add(1)
-		influxDBRegistry.BackendReqDurationHistogram().With("service", "test", "code", strconv.Itoa(http.StatusOK)).Observe(10000)
+		influxDBRegistry.BackendReqsCounter().With("backend", "test", "code", strconv.Itoa(http.StatusOK), "method", http.MethodGet).Add(1)
+		influxDBRegistry.BackendReqsCounter().With("backend", "test", "code", strconv.Itoa(http.StatusNotFound), "method", http.MethodGet).Add(1)
+		influxDBRegistry.BackendRetriesCounter().With("backend", "test").Add(1)
+		influxDBRegistry.BackendRetriesCounter().With("backend", "test").Add(1)
+		influxDBRegistry.BackendReqDurationHistogram().With("backend", "test", "code", strconv.Itoa(http.StatusOK)).Observe(10000)
 		influxDBRegistry.ConfigReloadsCounter().Add(1)
 		influxDBRegistry.ConfigReloadsFailureCounter().Add(1)
 		influxDBRegistry.BackendServerUpGauge().With("backend", "test", "url", "http://127.0.0.1").Set(1)
@@ -47,9 +47,9 @@ func TestInfluxDB(t *testing.T) {
 	assertMessage(t, msgBackend, expectedBackend)
 
 	expectedEntrypoint := []string{
-		`(traefik\.entrypoint\.requests\.total(?:,backend=test,code=[\d]{3})?,entrypoint=test(?:[a-z=0-9A-Z,:/.]+)? count=1) [\d]{19}`,
-		`(traefik\.entrypoint\.request\.duration(?:,backend=test,code=[\d]{3})?,entrypoint=test(?:[a-z=0-9A-Z,:/.]+)? p50=10000,p90=10000,p95=10000,p99=10000) [\d]{19}`,
-		`(traefik\.entrypoint\.connections\.open(?:[a-z=0-9A-Z,]+)?,entrypoint=test,(?:[a-z=0-9A-Z,:.//]+)? value=1) [\d]{19}`,
+		`(traefik\.entrypoint\.requests\.total,entrypoint=test(?:[a-z=0-9A-Z,:/.]+)? count=1) [\d]{19}`,
+		`(traefik\.entrypoint\.request\.duration(?:,code=[\d]{3})?,entrypoint=test(?:[a-z=0-9A-Z,:/.]+)? p50=10000,p90=10000,p95=10000,p99=10000) [\d]{19}`,
+		`(traefik\.entrypoint\.connections\.open,entrypoint=test value=1) [\d]{19}`,
 	}
 
 	msgEntrypoint := udp.ReceiveString(t, func() {

metrics/prometheus.go

@@ -335,6 +335,12 @@ func (g *gauge) With(labelValues ...string) metrics.Gauge {
 	}
 }
 
+func (g *gauge) Add(delta float64) {
+	collector := g.gv.With(g.labelNamesValues.ToLabels())
+	collector.Add(delta)
+	g.collectors <- newCollector(g.name, g.labelNamesValues, collector)
+}
+
 func (g *gauge) Set(value float64) {
 	collector := g.gv.With(g.labelNamesValues.ToLabels())
 	collector.Set(value)

testhelpers/metrics.go

@@ -32,7 +32,12 @@ func (g *CollectingGauge) With(labelValues ...string) metrics.Gauge {
 }
 
 // Set is there to satisfy the metrics.Gauge interface.
-func (g *CollectingGauge) Set(delta float64) {
+func (g *CollectingGauge) Set(value float64) {
+	g.GaugeValue = value
+}
+
+// Add is there to satisfy the metrics.Gauge interface.
+func (g *CollectingGauge) Add(delta float64) {
 	g.GaugeValue = delta
 }
 

vendor/github.com/go-kit/kit/log/doc.go

@@ -35,14 +35,15 @@
 // idea to log simple values without formatting them. This practice allows
 // the chosen logger to encode values in the most appropriate way.
 //
-// Log Context
+// Contextual Loggers
 //
-// A log context stores keyvals that it includes in all log events. Building
-// appropriate log contexts reduces repetition and aids consistency in the
-// resulting log output. We can use a context to improve the RunTask example.
+// A contextual logger stores keyvals that it includes in all log events.
+// Building appropriate contextual loggers reduces repetition and aids
+// consistency in the resulting log output. With and WithPrefix add context to
+// a logger. We can use With to improve the RunTask example.
 //
 //    func RunTask(task Task, logger log.Logger) string {
-//        logger = log.NewContext(logger).With("taskID", task.ID)
+//        logger = log.With(logger, "taskID", task.ID)
 //        logger.Log("event", "starting task")
 //        ...
 //        taskHelper(task.Cmd, logger)
@@ -51,19 +52,18 @@
 //    }
 //
 // The improved version emits the same log events as the original for the
-// first and last calls to Log. The call to taskHelper highlights that a
-// context may be passed as a logger to other functions. Each log event
-// created by the called function will include the task.ID even though the
-// function does not have access to that value. Using log contexts this way
-// simplifies producing log output that enables tracing the life cycle of
-// individual tasks. (See the Context example for the full code of the
-// above snippet.)
+// first and last calls to Log. Passing the contextual logger to taskHelper
+// enables each log event created by taskHelper to include the task.ID even
+// though taskHelper does not have access to that value. Using contextual
+// loggers this way simplifies producing log output that enables tracing the
+// life cycle of individual tasks. (See the Contextual example for the full
+// code of the above snippet.)
 //
-// Dynamic Context Values
+// Dynamic Contextual Values
 //
-// A Valuer function stored in a log context generates a new value each time
-// the context logs an event. The Valuer example demonstrates how this
-// feature works.
+// A Valuer function stored in a contextual logger generates a new value each
+// time an event is logged. The Valuer example demonstrates how this feature
+// works.
 //
 // Valuers provide the basis for consistently logging timestamps and source
 // code location. The log package defines several valuers for that purpose.
@@ -72,7 +72,7 @@
 // entries contain a timestamp and source location looks like this:
 //
 //    logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stdout))
-//    logger = log.NewContext(logger).With("ts", log.DefaultTimestampUTC, "caller", log.DefaultCaller)
+//    logger = log.With(logger, "ts", log.DefaultTimestampUTC, "caller", log.DefaultCaller)
 //
 // Concurrent Safety
 //
@@ -90,4 +90,27 @@
 // handled atomically within the wrapped logger, but it typically serializes
 // both the formatting and output logic. Use a SyncLogger if the formatting
 // logger may perform multiple writes per log event.
+//
+// Error Handling
+//
+// This package relies on the practice of wrapping or decorating loggers with
+// other loggers to provide composable pieces of functionality. It also means
+// that Logger.Log must return an error because some
+// implementations—especially those that output log data to an io.Writer—may
+// encounter errors that cannot be handled locally. This in turn means that
+// Loggers that wrap other loggers should return errors from the wrapped
+// logger up the stack.
+//
+// Fortunately, the decorator pattern also provides a way to avoid the
+// necessity to check for errors every time an application calls Logger.Log.
+// An application required to panic whenever its Logger encounters
+// an error could initialize its logger as follows.
+//
+//    fmtlogger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stdout))
+//    logger := log.LoggerFunc(func(keyvals ...interface{}) error {
+//        if err := fmtlogger.Log(keyvals...); err != nil {
+//            panic(err)
+//        }
+//        return nil
+//    })
 package log

vendor/github.com/go-kit/kit/log/json_logger.go

@@ -44,9 +44,6 @@ func merge(dst map[string]interface{}, k, v interface{}) {
 	default:
 		key = fmt.Sprint(x)
 	}
-	if x, ok := v.(error); ok {
-		v = safeError(x)
-	}
 
 	// We want json.Marshaler and encoding.TextMarshaller to take priority over
 	// err.Error() and v.String(). But json.Marshall (called later) does that by

vendor/github.com/go-kit/kit/log/log.go

@@ -6,7 +6,7 @@ import "errors"
 // log event from keyvals, a variadic sequence of alternating keys and values.
 // Implementations must be safe for concurrent use by multiple goroutines. In
 // particular, any implementation of Logger that appends to keyvals or
-// modifies any of its elements must make a copy first.
+// modifies or retains any of its elements must make a copy first.
 type Logger interface {
 	Log(keyvals ...interface{}) error
 }
@@ -15,62 +15,100 @@ type Logger interface {
 // the missing value.
 var ErrMissingValue = errors.New("(MISSING)")
 
-// NewContext returns a new Context that logs to logger.
-func NewContext(logger Logger) *Context {
-	if c, ok := logger.(*Context); ok {
-		return c
+// With returns a new contextual logger with keyvals prepended to those passed
+// to calls to Log. If logger is also a contextual logger created by With or
+// WithPrefix, keyvals is appended to the existing context.
+//
+// The returned Logger replaces all value elements (odd indexes) containing a
+// Valuer with their generated value for each call to its Log method.
+func With(logger Logger, keyvals ...interface{}) Logger {
+	if len(keyvals) == 0 {
+		return logger
+	}
+	l := newContext(logger)
+	kvs := append(l.keyvals, keyvals...)
+	if len(kvs)%2 != 0 {
+		kvs = append(kvs, ErrMissingValue)
+	}
+	return &context{
+		logger: l.logger,
+		// Limiting the capacity of the stored keyvals ensures that a new
+		// backing array is created if the slice must grow in Log or With.
+		// Using the extra capacity without copying risks a data race that
+		// would violate the Logger interface contract.
+		keyvals:   kvs[:len(kvs):len(kvs)],
+		hasValuer: l.hasValuer || containsValuer(keyvals),
 	}
-	return &Context{logger: logger}
 }
 
-// Context must always have the same number of stack frames between calls to
+// WithPrefix returns a new contextual logger with keyvals prepended to those
+// passed to calls to Log. If logger is also a contextual logger created by
+// With or WithPrefix, keyvals is prepended to the existing context.
+//
+// The returned Logger replaces all value elements (odd indexes) containing a
+// Valuer with their generated value for each call to its Log method.
+func WithPrefix(logger Logger, keyvals ...interface{}) Logger {
+	if len(keyvals) == 0 {
+		return logger
+	}
+	l := newContext(logger)
+	// Limiting the capacity of the stored keyvals ensures that a new
+	// backing array is created if the slice must grow in Log or With.
+	// Using the extra capacity without copying risks a data race that
+	// would violate the Logger interface contract.
+	n := len(l.keyvals) + len(keyvals)
+	if len(keyvals)%2 != 0 {
+		n++
+	}
+	kvs := make([]interface{}, 0, n)
+	kvs = append(kvs, keyvals...)
+	if len(kvs)%2 != 0 {
+		kvs = append(kvs, ErrMissingValue)
+	}
+	kvs = append(kvs, l.keyvals...)
+	return &context{
+		logger:    l.logger,
+		keyvals:   kvs,
+		hasValuer: l.hasValuer || containsValuer(keyvals),
+	}
+}
+
+// context is the Logger implementation returned by With and WithPrefix. It
+// wraps a Logger and holds keyvals that it includes in all log events. Its
+// Log method calls bindValues to generate values for each Valuer in the
+// context keyvals.
+//
+// A context must always have the same number of stack frames between calls to
 // its Log method and the eventual binding of Valuers to their value. This
 // requirement comes from the functional requirement to allow a context to
-// resolve application call site information for a log.Caller stored in the
+// resolve application call site information for a Caller stored in the
 // context. To do this we must be able to predict the number of logging
 // functions on the stack when bindValues is called.
 //
-// Three implementation details provide the needed stack depth consistency.
-// The first two of these details also result in better amortized performance,
-// and thus make sense even without the requirements regarding stack depth.
-// The third detail, however, is subtle and tied to the implementation of the
-// Go compiler.
+// Two implementation details provide the needed stack depth consistency.
 //
-//    1. NewContext avoids introducing an additional layer when asked to
-//       wrap another Context.
-//    2. With avoids introducing an additional layer by returning a newly
-//       constructed Context with a merged keyvals rather than simply
-//       wrapping the existing Context.
-//    3. All of Context's methods take pointer receivers even though they
-//       do not mutate the Context.
-//
-// Before explaining the last detail, first some background. The Go compiler
-// generates wrapper methods to implement the auto dereferencing behavior when
-// calling a value method through a pointer variable. These wrapper methods
-// are also used when calling a value method through an interface variable
-// because interfaces store a pointer to the underlying concrete value.
-// Calling a pointer receiver through an interface does not require generating
-// an additional function.
-//
-// If Context had value methods then calling Context.Log through a variable
-// with type Logger would have an extra stack frame compared to calling
-// Context.Log through a variable with type Context. Using pointer receivers
-// avoids this problem.
-
-// A Context wraps a Logger and holds keyvals that it includes in all log
-// events. When logging, a Context replaces all value elements (odd indexes)
-// containing a Valuer with their generated value for each call to its Log
-// method.
-type Context struct {
+//    1. newContext avoids introducing an additional layer when asked to
+//       wrap another context.
+//    2. With and WithPrefix avoid introducing an additional layer by
+//       returning a newly constructed context with a merged keyvals rather
+//       than simply wrapping the existing context.
+type context struct {
 	logger    Logger
 	keyvals   []interface{}
 	hasValuer bool
 }
 
+func newContext(logger Logger) *context {
+	if c, ok := logger.(*context); ok {
+		return c
+	}
+	return &context{logger: logger}
+}
+
 // Log replaces all value elements (odd indexes) containing a Valuer in the
 // stored context with their generated value, appends keyvals, and passes the
 // result to the wrapped Logger.
-func (l *Context) Log(keyvals ...interface{}) error {
+func (l *context) Log(keyvals ...interface{}) error {
 	kvs := append(l.keyvals, keyvals...)
 	if len(kvs)%2 != 0 {
 		kvs = append(kvs, ErrMissingValue)
@@ -86,53 +124,6 @@ func (l *Context) Log(keyvals ...interface{}) error {
 	return l.logger.Log(kvs...)
 }
 
-// With returns a new Context with keyvals appended to those of the receiver.
-func (l *Context) With(keyvals ...interface{}) *Context {
-	if len(keyvals) == 0 {
-		return l
-	}
-	kvs := append(l.keyvals, keyvals...)
-	if len(kvs)%2 != 0 {
-		kvs = append(kvs, ErrMissingValue)
-	}
-	return &Context{
-		logger: l.logger,
-		// Limiting the capacity of the stored keyvals ensures that a new
-		// backing array is created if the slice must grow in Log or With.
-		// Using the extra capacity without copying risks a data race that
-		// would violate the Logger interface contract.
-		keyvals:   kvs[:len(kvs):len(kvs)],
-		hasValuer: l.hasValuer || containsValuer(keyvals),
-	}
-}
-
-// WithPrefix returns a new Context with keyvals prepended to those of the
-// receiver.
-func (l *Context) WithPrefix(keyvals ...interface{}) *Context {
-	if len(keyvals) == 0 {
-		return l
-	}
-	// Limiting the capacity of the stored keyvals ensures that a new
-	// backing array is created if the slice must grow in Log or With.
-	// Using the extra capacity without copying risks a data race that
-	// would violate the Logger interface contract.
-	n := len(l.keyvals) + len(keyvals)
-	if len(keyvals)%2 != 0 {
-		n++
-	}
-	kvs := make([]interface{}, 0, n)
-	kvs = append(kvs, keyvals...)
-	if len(kvs)%2 != 0 {
-		kvs = append(kvs, ErrMissingValue)
-	}
-	kvs = append(kvs, l.keyvals...)
-	return &Context{
-		logger:    l.logger,
-		keyvals:   kvs,
-		hasValuer: l.hasValuer || containsValuer(keyvals),
-	}
-}
-
 // LoggerFunc is an adapter to allow use of ordinary functions as Loggers. If
 // f is a function with the appropriate signature, LoggerFunc(f) is a Logger
 // object that calls f.

vendor/github.com/go-kit/kit/log/stdlib.go

@@ -39,7 +39,7 @@ func TimestampKey(key string) StdlibAdapterOption {
 	return func(a *StdlibAdapter) { a.timestampKey = key }
 }
 
-// FileKey sets the key for the file and line field. By default, it's "file".
+// FileKey sets the key for the file and line field. By default, it's "caller".
 func FileKey(key string) StdlibAdapterOption {
 	return func(a *StdlibAdapter) { a.fileKey = key }
 }
@@ -55,7 +55,7 @@ func NewStdlibAdapter(logger Logger, options ...StdlibAdapterOption) io.Writer {
 	a := StdlibAdapter{
 		Logger:       logger,
 		timestampKey: "ts",
-		fileKey:      "file",
+		fileKey:      "caller",
 		messageKey:   "msg",
 	}
 	for _, option := range options {

vendor/github.com/go-kit/kit/log/sync.go

@@ -36,24 +36,59 @@ func (l *SwapLogger) Swap(logger Logger) {
 	l.logger.Store(loggerStruct{logger})
 }
 
-// SyncWriter synchronizes concurrent writes to an io.Writer.
-type SyncWriter struct {
-	mu sync.Mutex
-	w  io.Writer
+// NewSyncWriter returns a new writer that is safe for concurrent use by
+// multiple goroutines. Writes to the returned writer are passed on to w. If
+// another write is already in progress, the calling goroutine blocks until
+// the writer is available.
+//
+// If w implements the following interface, so does the returned writer.
+//
+//    interface {
+//        Fd() uintptr
+//    }
+func NewSyncWriter(w io.Writer) io.Writer {
+	switch w := w.(type) {
+	case fdWriter:
+		return &fdSyncWriter{fdWriter: w}
+	default:
+		return &syncWriter{Writer: w}
+	}
 }
 
-// NewSyncWriter returns a new SyncWriter. The returned writer is safe for
-// concurrent use by multiple goroutines.
-func NewSyncWriter(w io.Writer) *SyncWriter {
-	return &SyncWriter{w: w}
+// syncWriter synchronizes concurrent writes to an io.Writer.
+type syncWriter struct {
+	sync.Mutex
+	io.Writer
 }
 
 // Write writes p to the underlying io.Writer. If another write is already in
-// progress, the calling goroutine blocks until the SyncWriter is available.
-func (w *SyncWriter) Write(p []byte) (n int, err error) {
-	w.mu.Lock()
-	n, err = w.w.Write(p)
-	w.mu.Unlock()
+// progress, the calling goroutine blocks until the syncWriter is available.
+func (w *syncWriter) Write(p []byte) (n int, err error) {
+	w.Lock()
+	n, err = w.Writer.Write(p)
+	w.Unlock()
+	return n, err
+}
+
+// fdWriter is an io.Writer that also has an Fd method. The most common
+// example of an fdWriter is an *os.File.
+type fdWriter interface {
+	io.Writer
+	Fd() uintptr
+}
+
+// fdSyncWriter synchronizes concurrent writes to an fdWriter.
+type fdSyncWriter struct {
+	sync.Mutex
+	fdWriter
+}
+
+// Write writes p to the underlying io.Writer. If another write is already in
+// progress, the calling goroutine blocks until the fdSyncWriter is available.
+func (w *fdSyncWriter) Write(p []byte) (n int, err error) {
+	w.Lock()
+	n, err = w.fdWriter.Write(p)
+	w.Unlock()
 	return n, err
 }
 

vendor/github.com/go-kit/kit/log/value.go

@@ -6,9 +6,9 @@ import (
 	"github.com/go-stack/stack"
 )
 
-// A Valuer generates a log value. When passed to Context.With in a value
-// element (odd indexes), it represents a dynamic value which is re-evaluated
-// with each log event.
+// A Valuer generates a log value. When passed to With or WithPrefix in a
+// value element (odd indexes), it represents a dynamic value which is re-
+// evaluated with each log event.
 type Valuer func() interface{}
 
 // bindValues replaces all value elements (odd indexes) containing a Valuer
@@ -32,22 +32,51 @@ func containsValuer(keyvals []interface{}) bool {
 	return false
 }
 
-// Timestamp returns a Valuer that invokes the underlying function when bound,
-// returning a time.Time. Users will probably want to use DefaultTimestamp or
-// DefaultTimestampUTC.
+// Timestamp returns a timestamp Valuer. It invokes the t function to get the
+// time; unless you are doing something tricky, pass time.Now.
+//
+// Most users will want to use DefaultTimestamp or DefaultTimestampUTC, which
+// are TimestampFormats that use the RFC3339Nano format.
 func Timestamp(t func() time.Time) Valuer {
 	return func() interface{} { return t() }
 }
 
-var (
-	// DefaultTimestamp is a Valuer that returns the current wallclock time,
-	// respecting time zones, when bound.
-	DefaultTimestamp Valuer = func() interface{} { return time.Now().Format(time.RFC3339) }
+// TimestampFormat returns a timestamp Valuer with a custom time format. It
+// invokes the t function to get the time to format; unless you are doing
+// something tricky, pass time.Now. The layout string is passed to
+// Time.Format.
+//
+// Most users will want to use DefaultTimestamp or DefaultTimestampUTC, which
+// are TimestampFormats that use the RFC3339Nano format.
+func TimestampFormat(t func() time.Time, layout string) Valuer {
+	return func() interface{} {
+		return timeFormat{
+			time:   t(),
+			layout: layout,
+		}
+	}
+}
 
-	// DefaultTimestampUTC is a Valuer that returns the current time in UTC
-	// when bound.
-	DefaultTimestampUTC Valuer = func() interface{} { return time.Now().UTC().Format(time.RFC3339) }
-)
+// A timeFormat represents an instant in time and a layout used when
+// marshaling to a text format.
+type timeFormat struct {
+	time   time.Time
+	layout string
+}
+
+func (tf timeFormat) String() string {
+	return tf.time.Format(tf.layout)
+}
+
+// MarshalText implements encoding.TextMarshaller.
+func (tf timeFormat) MarshalText() (text []byte, err error) {
+	// The following code adapted from the standard library time.Time.Format
+	// method. Using the same undocumented magic constant to extend the size
+	// of the buffer as seen there.
+	b := make([]byte, 0, len(tf.layout)+10)
+	b = tf.time.AppendFormat(b, tf.layout)
+	return b, nil
+}
 
 // Caller returns a Valuer that returns a file and line from a specified depth
 // in the callstack. Users will probably want to use DefaultCaller.
@@ -56,6 +85,17 @@ func Caller(depth int) Valuer {
 }
 
 var (
+	// DefaultTimestamp is a Valuer that returns the current wallclock time,
+	// respecting time zones, when bound.
+	DefaultTimestamp = TimestampFormat(time.Now, time.RFC3339Nano)
+
+	// DefaultTimestampUTC is a Valuer that returns the current time in UTC
+	// when bound.
+	DefaultTimestampUTC = TimestampFormat(
+		func() time.Time { return time.Now().UTC() },
+		time.RFC3339Nano,
+	)
+
 	// DefaultCaller is a Valuer that returns the file and line where the Log
 	// method was invoked. It can only be used with log.With.
 	DefaultCaller = Caller(3)

vendor/github.com/go-kit/kit/metrics/doc.go

@@ -1,23 +1,54 @@
-// Package metrics provides a framework for application instrumentation. All
-// metrics are safe for concurrent use. Considerable design influence has been
-// taken from https://github.com/codahale/metrics and https://prometheus.io.
+// Package metrics provides a framework for application instrumentation. It's
+// primarily designed to help you get started with good and robust
+// instrumentation, and to help you migrate from a less-capable system like
+// Graphite to a more-capable system like Prometheus. If your organization has
+// already standardized on an instrumentation system like Prometheus, and has no
+// plans to change, it may make sense to use that system's instrumentation
+// library directly.
 //
-// This package contains the common interfaces. Your code should take these
-// interfaces as parameters. Implementations are provided for different
-// instrumentation systems in the various subdirectories.
+// This package provides three core metric abstractions (Counter, Gauge, and
+// Histogram) and implementations for almost all common instrumentation
+// backends. Each metric has an observation method (Add, Set, or Observe,
+// respectively) used to record values, and a With method to "scope" the
+// observation by various parameters. For example, you might have a Histogram to
+// record request durations, parameterized by the method that's being called.
+//
+//    var requestDuration metrics.Histogram
+//    // ...
+//    requestDuration.With("method", "MyMethod").Observe(time.Since(begin))
+//
+// This allows a single high-level metrics object (requestDuration) to work with
+// many code paths somewhat dynamically. The concept of With is fully supported
+// in some backends like Prometheus, and not supported in other backends like
+// Graphite. So, With may be a no-op, depending on the concrete implementation
+// you choose. Please check the implementation to know for sure. For
+// implementations that don't provide With, it's necessary to fully parameterize
+// each metric in the metric name, e.g.
+//
+//    // Statsd
+//    c := statsd.NewCounter("request_duration_MyMethod_200")
+//    c.Add(1)
+//
+//    // Prometheus
+//    c := prometheus.NewCounter(stdprometheus.CounterOpts{
+//        Name: "request_duration",
+//        ...
+//    }, []string{"method", "status_code"})
+//    c.With("method", "MyMethod", "status_code", strconv.Itoa(code)).Add(1)
 //
 // Usage
 //
-// Metrics are dependencies and should be passed to the components that need
+// Metrics are dependencies, and should be passed to the components that need
 // them in the same way you'd construct and pass a database handle, or reference
-// to another component. So, create metrics in your func main, using whichever
-// concrete implementation is appropriate for your organization.
+// to another component. Metrics should *not* be created in the global scope.
+// Instead, instantiate metrics in your func main, using whichever concrete
+// implementation is appropriate for your organization.
 //
 //    latency := prometheus.NewSummaryFrom(stdprometheus.SummaryOpts{
 //        Namespace: "myteam",
 //        Subsystem: "foosvc",
 //        Name:      "request_latency_seconds",
-//        Help:      "Incoming request latency in seconds."
+//        Help:      "Incoming request latency in seconds.",
 //    }, []string{"method", "status_code"})
 //
 // Write your components to take the metrics they will use as parameters to
@@ -40,8 +71,14 @@
 //    api := NewAPI(store, logger, latency)
 //    http.ListenAndServe("/", api)
 //
+// Note that metrics are "write-only" interfaces.
+//
 // Implementation details
 //
+// All metrics are safe for concurrent use. Considerable design influence has
+// been taken from https://github.com/codahale/metrics and
+// https://prometheus.io.
+//
 // Each telemetry system has different semantics for label values, push vs.
 // pull, support for histograms, etc. These properties influence the design of
 // their respective packages. This table attempts to summarize the key points of
@@ -54,7 +91,7 @@
 //    expvar      1    atomic                 atomic                 synthetic, batch, in-place expose
 //    influx      n    custom                 custom                 custom
 //    prometheus  n    native                 native                 native
-//    circonus    1    native                 native                 native
 //    pcp         1    native                 native                 native
+//    cloudwatch  n    batch push-aggregate   batch push-aggregate   synthetic, batch, push-aggregate
 //
 package metrics

vendor/github.com/go-kit/kit/metrics/dogstatsd/dogstatsd.go

@@ -14,10 +14,13 @@ import (
 	"fmt"
 	"io"
 	"strings"
+	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/metrics"
+	"github.com/go-kit/kit/metrics/generic"
 	"github.com/go-kit/kit/metrics/internal/lv"
 	"github.com/go-kit/kit/metrics/internal/ratemap"
 	"github.com/go-kit/kit/util/conn"
@@ -34,53 +37,63 @@ import (
 // To regularly report metrics to an io.Writer, use the WriteLoop helper method.
 // To send to a DogStatsD server, use the SendLoop helper method.
 type Dogstatsd struct {
+	mtx        sync.RWMutex
 	prefix     string
 	rates      *ratemap.RateMap
 	counters   *lv.Space
-	gauges     *lv.Space
+	gauges     map[string]*gaugeNode
 	timings    *lv.Space
 	histograms *lv.Space
 	logger     log.Logger
+	lvs        lv.LabelValues
 }
 
 // New returns a Dogstatsd object that may be used to create metrics. Prefix is
 // applied to all created metrics. Callers must ensure that regular calls to
 // WriteTo are performed, either manually or with one of the helper methods.
-func New(prefix string, logger log.Logger) *Dogstatsd {
+func New(prefix string, logger log.Logger, lvs ...string) *Dogstatsd {
+	if len(lvs)%2 != 0 {
+		panic("odd number of LabelValues; programmer error!")
+	}
 	return &Dogstatsd{
 		prefix:     prefix,
 		rates:      ratemap.New(),
 		counters:   lv.NewSpace(),
-		gauges:     lv.NewSpace(),
+		gauges:     map[string]*gaugeNode{},
 		timings:    lv.NewSpace(),
 		histograms: lv.NewSpace(),
 		logger:     logger,
+		lvs:        lvs,
 	}
 }
 
 // NewCounter returns a counter, sending observations to this Dogstatsd object.
 func (d *Dogstatsd) NewCounter(name string, sampleRate float64) *Counter {
-	d.rates.Set(d.prefix+name, sampleRate)
+	d.rates.Set(name, sampleRate)
 	return &Counter{
-		name: d.prefix + name,
+		name: name,
 		obs:  d.counters.Observe,
 	}
 }
 
 // NewGauge returns a gauge, sending observations to this Dogstatsd object.
 func (d *Dogstatsd) NewGauge(name string) *Gauge {
-	return &Gauge{
-		name: d.prefix + name,
-		obs:  d.gauges.Observe,
+	d.mtx.Lock()
+	n, ok := d.gauges[name]
+	if !ok {
+		n = &gaugeNode{gauge: &Gauge{g: generic.NewGauge(name), ddog: d}}
+		d.gauges[name] = n
 	}
+	d.mtx.Unlock()
+	return n.gauge
 }
 
 // NewTiming returns a histogram whose observations are interpreted as
 // millisecond durations, and are forwarded to this Dogstatsd object.
 func (d *Dogstatsd) NewTiming(name string, sampleRate float64) *Timing {
-	d.rates.Set(d.prefix+name, sampleRate)
+	d.rates.Set(name, sampleRate)
 	return &Timing{
-		name: d.prefix + name,
+		name: name,
 		obs:  d.timings.Observe,
 	}
 }
@@ -88,9 +101,9 @@ func (d *Dogstatsd) NewTiming(name string, sampleRate float64) *Timing {
 // NewHistogram returns a histogram whose observations are of an unspecified
 // unit, and are forwarded to this Dogstatsd object.
 func (d *Dogstatsd) NewHistogram(name string, sampleRate float64) *Histogram {
-	d.rates.Set(d.prefix+name, sampleRate)
+	d.rates.Set(name, sampleRate)
 	return &Histogram{
-		name: d.prefix + name,
+		name: name,
 		obs:  d.histograms.Observe,
 	}
 }
@@ -124,7 +137,7 @@ func (d *Dogstatsd) WriteTo(w io.Writer) (count int64, err error) {
 	var n int
 
 	d.counters.Reset().Walk(func(name string, lvs lv.LabelValues, values []float64) bool {
-		n, err = fmt.Fprintf(w, "%s:%f|c%s%s\n", name, sum(values), sampling(d.rates.Get(name)), tagValues(lvs))
+		n, err = fmt.Fprintf(w, "%s%s:%f|c%s%s\n", d.prefix, name, sum(values), sampling(d.rates.Get(name)), d.tagValues(lvs))
 		if err != nil {
 			return false
 		}
@@ -135,22 +148,23 @@ func (d *Dogstatsd) WriteTo(w io.Writer) (count int64, err error) {
 		return count, err
 	}
 
-	d.gauges.Reset().Walk(func(name string, lvs lv.LabelValues, values []float64) bool {
-		n, err = fmt.Fprintf(w, "%s:%f|g%s\n", name, last(values), tagValues(lvs))
-		if err != nil {
-			return false
-		}
-		count += int64(n)
-		return true
-	})
-	if err != nil {
-		return count, err
+	d.mtx.RLock()
+	for _, root := range d.gauges {
+		root.walk(func(name string, lvs lv.LabelValues, value float64) bool {
+			n, err = fmt.Fprintf(w, "%s%s:%f|g%s\n", d.prefix, name, value, d.tagValues(lvs))
+			if err != nil {
+				return false
+			}
+			count += int64(n)
+			return true
+		})
 	}
+	d.mtx.RUnlock()
 
 	d.timings.Reset().Walk(func(name string, lvs lv.LabelValues, values []float64) bool {
 		sampleRate := d.rates.Get(name)
 		for _, value := range values {
-			n, err = fmt.Fprintf(w, "%s:%f|ms%s%s\n", name, value, sampling(sampleRate), tagValues(lvs))
+			n, err = fmt.Fprintf(w, "%s%s:%f|ms%s%s\n", d.prefix, name, value, sampling(sampleRate), d.tagValues(lvs))
 			if err != nil {
 				return false
 			}
@@ -165,7 +179,7 @@ func (d *Dogstatsd) WriteTo(w io.Writer) (count int64, err error) {
 	d.histograms.Reset().Walk(func(name string, lvs lv.LabelValues, values []float64) bool {
 		sampleRate := d.rates.Get(name)
 		for _, value := range values {
-			n, err = fmt.Fprintf(w, "%s:%f|h%s%s\n", name, value, sampling(sampleRate), tagValues(lvs))
+			n, err = fmt.Fprintf(w, "%s%s:%f|h%s%s\n", d.prefix, name, value, sampling(sampleRate), d.tagValues(lvs))
 			if err != nil {
 				return false
 			}
@@ -200,14 +214,17 @@ func sampling(r float64) string {
 	return sv
 }
 
-func tagValues(labelValues []string) string {
-	if len(labelValues) == 0 {
+func (d *Dogstatsd) tagValues(labelValues []string) string {
+	if len(labelValues) == 0 && len(d.lvs) == 0 {
 		return ""
 	}
 	if len(labelValues)%2 != 0 {
 		panic("tagValues received a labelValues with an odd number of strings")
 	}
-	pairs := make([]string, 0, len(labelValues)/2)
+	pairs := make([]string, 0, (len(d.lvs)+len(labelValues))/2)
+	for i := 0; i < len(d.lvs); i += 2 {
+		pairs = append(pairs, d.lvs[i]+":"+d.lvs[i+1])
+	}
 	for i := 0; i < len(labelValues); i += 2 {
 		pairs = append(pairs, labelValues[i]+":"+labelValues[i+1])
 	}
@@ -241,23 +258,31 @@ func (c *Counter) Add(delta float64) {
 // Gauge is a DogStatsD gauge. Observations are forwarded to a Dogstatsd
 // object, and aggregated (the last observation selected) per timeseries.
 type Gauge struct {
-	name string
-	lvs  lv.LabelValues
-	obs  observeFunc
+	g    *generic.Gauge
+	ddog *Dogstatsd
+	set  int32
 }
 
 // With implements metrics.Gauge.
 func (g *Gauge) With(labelValues ...string) metrics.Gauge {
-	return &Gauge{
-		name: g.name,
-		lvs:  g.lvs.With(labelValues...),
-		obs:  g.obs,
-	}
+	g.ddog.mtx.RLock()
+	node := g.ddog.gauges[g.g.Name]
+	g.ddog.mtx.RUnlock()
+
+	ga := &Gauge{g: g.g.With(labelValues...).(*generic.Gauge), ddog: g.ddog}
+	return node.addGauge(ga, ga.g.LabelValues())
 }
 
 // Set implements metrics.Gauge.
 func (g *Gauge) Set(value float64) {
-	g.obs(g.name, g.lvs, value)
+	g.g.Set(value)
+	g.touch()
+}
+
+// Add implements metrics.Gauge.
+func (g *Gauge) Add(delta float64) {
+	g.g.Add(delta)
+	g.touch()
 }
 
 // Timing is a DogStatsD timing, or metrics.Histogram. Observations are
@@ -304,3 +329,61 @@ func (h *Histogram) With(labelValues ...string) metrics.Histogram {
 func (h *Histogram) Observe(value float64) {
 	h.obs(h.name, h.lvs, value)
 }
+
+type pair struct{ label, value string }
+
+type gaugeNode struct {
+	mtx      sync.RWMutex
+	gauge    *Gauge
+	children map[pair]*gaugeNode
+}
+
+func (n *gaugeNode) addGauge(g *Gauge, lvs lv.LabelValues) *Gauge {
+	n.mtx.Lock()
+	defer n.mtx.Unlock()
+	if len(lvs) == 0 {
+		if n.gauge == nil {
+			n.gauge = g
+		}
+		return n.gauge
+	}
+	if len(lvs) < 2 {
+		panic("too few LabelValues; programmer error!")
+	}
+	head, tail := pair{lvs[0], lvs[1]}, lvs[2:]
+	if n.children == nil {
+		n.children = map[pair]*gaugeNode{}
+	}
+	child, ok := n.children[head]
+	if !ok {
+		child = &gaugeNode{}
+		n.children[head] = child
+	}
+	return child.addGauge(g, tail)
+}
+
+func (n *gaugeNode) walk(fn func(string, lv.LabelValues, float64) bool) bool {
+	n.mtx.RLock()
+	defer n.mtx.RUnlock()
+	if n.gauge != nil {
+		value, ok := n.gauge.read()
+		if ok && !fn(n.gauge.g.Name, n.gauge.g.LabelValues(), value) {
+			return false
+		}
+	}
+	for _, child := range n.children {
+		if !child.walk(fn) {
+			return false
+		}
+	}
+	return true
+}
+
+func (g *Gauge) touch() {
+	atomic.StoreInt32(&(g.set), 1)
+}
+
+func (g *Gauge) read() (float64, bool) {
+	set := atomic.SwapInt32(&(g.set), 0)
+	return g.g.Value(), set != 0
+}

vendor/github.com/go-kit/kit/metrics/generic/generic.go

@@ -33,6 +33,7 @@ func NewCounter(name string) *Counter {
 // With implements Counter.
 func (c *Counter) With(labelValues ...string) metrics.Counter {
 	return &Counter{
+		Name: c.Name,
 		bits: atomic.LoadUint64(&c.bits),
 		lvs:  c.lvs.With(labelValues...),
 	}
@@ -95,6 +96,7 @@ func NewGauge(name string) *Gauge {
 // With implements Gauge.
 func (g *Gauge) With(labelValues ...string) metrics.Gauge {
 	return &Gauge{
+		Name: g.Name,
 		bits: atomic.LoadUint64(&g.bits),
 		lvs:  g.lvs.With(labelValues...),
 	}
@@ -105,6 +107,20 @@ func (g *Gauge) Set(value float64) {
 	atomic.StoreUint64(&g.bits, math.Float64bits(value))
 }
 
+// Add implements metrics.Gauge.
+func (g *Gauge) Add(delta float64) {
+	for {
+		var (
+			old  = atomic.LoadUint64(&g.bits)
+			newf = math.Float64frombits(old) + delta
+			new  = math.Float64bits(newf)
+		)
+		if atomic.CompareAndSwapUint64(&g.bits, old, new) {
+			break
+		}
+	}
+}
+
 // Value returns the current value of the gauge.
 func (g *Gauge) Value() float64 {
 	return math.Float64frombits(atomic.LoadUint64(&g.bits))
@@ -121,7 +137,7 @@ func (g *Gauge) LabelValues() []string {
 type Histogram struct {
 	Name string
 	lvs  lv.LabelValues
-	h    gohistogram.Histogram
+	h    *safeHistogram
 }
 
 // NewHistogram returns a numeric histogram based on VividCortex/gohistogram. A
@@ -129,25 +145,30 @@ type Histogram struct {
 func NewHistogram(name string, buckets int) *Histogram {
 	return &Histogram{
 		Name: name,
-		h:    gohistogram.NewHistogram(buckets),
+		h:    &safeHistogram{Histogram: gohistogram.NewHistogram(buckets)},
 	}
 }
 
 // With implements Histogram.
 func (h *Histogram) With(labelValues ...string) metrics.Histogram {
 	return &Histogram{
-		lvs: h.lvs.With(labelValues...),
-		h:   h.h,
+		Name: h.Name,
+		lvs:  h.lvs.With(labelValues...),
+		h:    h.h,
 	}
 }
 
 // Observe implements Histogram.
 func (h *Histogram) Observe(value float64) {
+	h.h.Lock()
+	defer h.h.Unlock()
 	h.h.Add(value)
 }
 
 // Quantile returns the value of the quantile q, 0.0 < q < 1.0.
 func (h *Histogram) Quantile(q float64) float64 {
+	h.h.RLock()
+	defer h.h.RUnlock()
 	return h.h.Quantile(q)
 }
 
@@ -159,9 +180,17 @@ func (h *Histogram) LabelValues() []string {
 // Print writes a string representation of the histogram to the passed writer.
 // Useful for printing to a terminal.
 func (h *Histogram) Print(w io.Writer) {
+	h.h.RLock()
+	defer h.h.RUnlock()
 	fmt.Fprintf(w, h.h.String())
 }
 
+// safeHistogram exists as gohistogram.Histogram is not goroutine-safe.
+type safeHistogram struct {
+	sync.RWMutex
+	gohistogram.Histogram
+}
+
 // Bucket is a range in a histogram which aggregates observations.
 type Bucket struct {
 	From, To, Count int64

vendor/github.com/go-kit/kit/metrics/influx/influx.go

@@ -66,6 +66,7 @@ func (in *Influx) NewGauge(name string) *Gauge {
 	return &Gauge{
 		name: name,
 		obs:  in.gauges.Observe,
+		add:  in.gauges.Add,
 	}
 }
 
@@ -168,10 +169,14 @@ func mergeTags(tags map[string]string, labelValues []string) map[string]string {
 	if len(labelValues)%2 != 0 {
 		panic("mergeTags received a labelValues with an odd number of strings")
 	}
-	for i := 0; i < len(labelValues); i += 2 {
-		tags[labelValues[i]] = labelValues[i+1]
+	ret := make(map[string]string, len(tags)+len(labelValues)/2)
+	for k, v := range tags {
+		ret[k] = v
 	}
-	return tags
+	for i := 0; i < len(labelValues); i += 2 {
+		ret[labelValues[i]] = labelValues[i+1]
+	}
+	return ret
 }
 
 func sum(a []float64) float64 {
@@ -216,6 +221,7 @@ type Gauge struct {
 	name string
 	lvs  lv.LabelValues
 	obs  observeFunc
+	add  observeFunc
 }
 
 // With implements metrics.Gauge.
@@ -224,6 +230,7 @@ func (g *Gauge) With(labelValues ...string) metrics.Gauge {
 		name: g.name,
 		lvs:  g.lvs.With(labelValues...),
 		obs:  g.obs,
+		add:  g.add,
 	}
 }
 
@@ -232,6 +239,11 @@ func (g *Gauge) Set(value float64) {
 	g.obs(g.name, g.lvs, value)
 }
 
+// Add implements metrics.Gauge.
+func (g *Gauge) Add(delta float64) {
+	g.add(g.name, g.lvs, delta)
+}
+
 // Histogram is an Influx histrogram. Observations are aggregated into a
 // generic.Histogram and emitted as per-quantile gauges to the Influx server.
 type Histogram struct {

vendor/github.com/go-kit/kit/metrics/internal/lv/space.go

@@ -21,6 +21,13 @@ func (s *Space) Observe(name string, lvs LabelValues, value float64) {
 	s.nodeFor(name).observe(lvs, value)
 }
 
+// Add locates the time series identified by the name and label values in
+// the vector space, and appends the delta to the last value in the list of
+// observations.
+func (s *Space) Add(name string, lvs LabelValues, delta float64) {
+	s.nodeFor(name).add(lvs, delta)
+}
+
 // Walk traverses the vector space and invokes fn for each non-empty time series
 // which is encountered. Return false to abort the traversal.
 func (s *Space) Walk(fn func(name string, lvs LabelValues, observations []float64) bool) {
@@ -91,6 +98,34 @@ func (n *node) observe(lvs LabelValues, value float64) {
 	child.observe(tail, value)
 }
 
+func (n *node) add(lvs LabelValues, delta float64) {
+	n.mtx.Lock()
+	defer n.mtx.Unlock()
+	if len(lvs) == 0 {
+		var value float64
+		if len(n.observations) > 0 {
+			value = last(n.observations) + delta
+		} else {
+			value = delta
+		}
+		n.observations = append(n.observations, value)
+		return
+	}
+	if len(lvs) < 2 {
+		panic("too few LabelValues; programmer error!")
+	}
+	head, tail := pair{lvs[0], lvs[1]}, lvs[2:]
+	if n.children == nil {
+		n.children = map[pair]*node{}
+	}
+	child, ok := n.children[head]
+	if !ok {
+		child = &node{}
+		n.children[head] = child
+	}
+	child.add(tail, delta)
+}
+
 func (n *node) walk(lvs LabelValues, fn func(LabelValues, []float64) bool) bool {
 	n.mtx.RLock()
 	defer n.mtx.RUnlock()
@@ -104,3 +139,7 @@ func (n *node) walk(lvs LabelValues, fn func(LabelValues, []float64) bool) bool
 	}
 	return true
 }
+
+func last(a []float64) float64 {
+	return a[len(a)-1]
+}

vendor/github.com/go-kit/kit/metrics/metrics.go

@@ -12,6 +12,7 @@ type Counter interface {
 type Gauge interface {
 	With(labelValues ...string) Gauge
 	Set(value float64)
+	Add(delta float64)
 }
 
 // Histogram describes a metric that takes repeated observations of the same

vendor/github.com/go-kit/kit/metrics/multi/multi.go

@@ -54,6 +54,13 @@ func (g Gauge) With(labelValues ...string) metrics.Gauge {
 	return next
 }
 
+// Add implements metrics.Gauge.
+func (g Gauge) Add(delta float64) {
+	for _, gauge := range g {
+		gauge.Add(delta)
+	}
+}
+
 // Histogram collects multiple individual histograms and treats them as a unit.
 type Histogram []metrics.Histogram
 

vendor/github.com/go-kit/kit/metrics/statsd/statsd.go

@@ -74,6 +74,7 @@ func (s *Statsd) NewGauge(name string) *Gauge {
 	return &Gauge{
 		name: s.prefix + name,
 		obs:  s.gauges.Observe,
+		add:  s.gauges.Add,
 	}
 }
 
@@ -201,6 +202,7 @@ func (c *Counter) Add(delta float64) {
 type Gauge struct {
 	name string
 	obs  observeFunc
+	add  observeFunc
 }
 
 // With is a no-op.
@@ -213,6 +215,11 @@ func (g *Gauge) Set(value float64) {
 	g.obs(g.name, lv.LabelValues{}, value)
 }
 
+// Add implements metrics.Gauge.
+func (g *Gauge) Add(delta float64) {
+	g.add(g.name, lv.LabelValues{}, delta)
+}
+
 // Timing is a StatsD timing, or metrics.Histogram. Observations are
 // forwarded to a Statsd object, and collected (but not aggregated) per
 // timeseries.

vendor/github.com/go-kit/kit/metrics/timer.go

@@ -7,6 +7,7 @@ import "time"
 type Timer struct {
 	h Histogram
 	t time.Time
+	u time.Duration
 }
 
 // NewTimer wraps the given histogram and records the current time.
@@ -14,15 +15,22 @@ func NewTimer(h Histogram) *Timer {
 	return &Timer{
 		h: h,
 		t: time.Now(),
+		u: time.Second,
 	}
 }
 
 // ObserveDuration captures the number of seconds since the timer was
 // constructed, and forwards that observation to the histogram.
 func (t *Timer) ObserveDuration() {
-	d := time.Since(t.t).Seconds()
+	d := float64(time.Since(t.t).Nanoseconds()) / float64(t.u)
 	if d < 0 {
 		d = 0
 	}
 	t.h.Observe(d)
 }
+
+// Unit sets the unit of the float64 emitted by the timer.
+// By default, the timer emits seconds.
+func (t *Timer) Unit(u time.Duration) {
+	t.u = u
+}