metrics: pull library and introduce ResettingTimer and InfluxDB reporter (#15910)

* go-metrics: fork library and introduce ResettingTimer and InfluxDB reporter.

* vendor: change nonsense/go-metrics to ethersphere/go-metrics

* go-metrics: add tests. move ResettingTimer logic from reporter to type.

* all, metrics: pull in metrics package in go-ethereum

* metrics/test: make sure metrics are enabled for tests

* metrics: apply gosimple rules

* metrics/exp, internal/debug: init expvar endpoint when starting pprof server

* internal/debug: tiny comment formatting fix

2 files changed, 747 insertions, 0 deletions

diff --git a/vendor/github.com/influxdata/influxdb/client/v2/client.go b/vendor/github.com/influxdata/influxdb/client/v2/client.go
new file mode 100644
index 000000000..77d44f2b3
--- /dev/null
+++ b/vendor/github.com/influxdata/influxdb/client/v2/client.go
@@ -0,0 +1,635 @@
+// Package client (v2) is the current official Go client for InfluxDB.
+package client // import "github.com/influxdata/influxdb/client/v2"
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"mime"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/influxdata/influxdb/models"
+)
+
+// HTTPConfig is the config data needed to create an HTTP Client.
+type HTTPConfig struct {
+	// Addr should be of the form "http://host:port"
+	// or "http://[ipv6-host%zone]:port".
+	Addr string
+
+	// Username is the influxdb username, optional.
+	Username string
+
+	// Password is the influxdb password, optional.
+	Password string
+
+	// UserAgent is the http User Agent, defaults to "InfluxDBClient".
+	UserAgent string
+
+	// Timeout for influxdb writes, defaults to no timeout.
+	Timeout time.Duration
+
+	// InsecureSkipVerify gets passed to the http client, if true, it will
+	// skip https certificate verification. Defaults to false.
+	InsecureSkipVerify bool
+
+	// TLSConfig allows the user to set their own TLS config for the HTTP
+	// Client. If set, this option overrides InsecureSkipVerify.
+	TLSConfig *tls.Config
+}
+
+// BatchPointsConfig is the config data needed to create an instance of the BatchPoints struct.
+type BatchPointsConfig struct {
+	// Precision is the write precision of the points, defaults to "ns".
+	Precision string
+
+	// Database is the database to write points to.
+	Database string
+
+	// RetentionPolicy is the retention policy of the points.
+	RetentionPolicy string
+
+	// Write consistency is the number of servers required to confirm write.
+	WriteConsistency string
+}
+
+// Client is a client interface for writing & querying the database.
+type Client interface {
+	// Ping checks that status of cluster, and will always return 0 time and no
+	// error for UDP clients.
+	Ping(timeout time.Duration) (time.Duration, string, error)
+
+	// Write takes a BatchPoints object and writes all Points to InfluxDB.
+	Write(bp BatchPoints) error
+
+	// Query makes an InfluxDB Query on the database. This will fail if using
+	// the UDP client.
+	Query(q Query) (*Response, error)
+
+	// Close releases any resources a Client may be using.
+	Close() error
+}
+
+// NewHTTPClient returns a new Client from the provided config.
+// Client is safe for concurrent use by multiple goroutines.
+func NewHTTPClient(conf HTTPConfig) (Client, error) {
+	if conf.UserAgent == "" {
+		conf.UserAgent = "InfluxDBClient"
+	}
+
+	u, err := url.Parse(conf.Addr)
+	if err != nil {
+		return nil, err
+	} else if u.Scheme != "http" && u.Scheme != "https" {
+		m := fmt.Sprintf("Unsupported protocol scheme: %s, your address"+
+			" must start with http:// or https://", u.Scheme)
+		return nil, errors.New(m)
+	}
+
+	tr := &http.Transport{
+		TLSClientConfig: &tls.Config{
+			InsecureSkipVerify: conf.InsecureSkipVerify,
+		},
+	}
+	if conf.TLSConfig != nil {
+		tr.TLSClientConfig = conf.TLSConfig
+	}
+	return &client{
+		url:       *u,
+		username:  conf.Username,
+		password:  conf.Password,
+		useragent: conf.UserAgent,
+		httpClient: &http.Client{
+			Timeout:   conf.Timeout,
+			Transport: tr,
+		},
+		transport: tr,
+	}, nil
+}
+
+// Ping will check to see if the server is up with an optional timeout on waiting for leader.
+// Ping returns how long the request took, the version of the server it connected to, and an error if one occurred.
+func (c *client) Ping(timeout time.Duration) (time.Duration, string, error) {
+	now := time.Now()
+	u := c.url
+	u.Path = "ping"
+
+	req, err := http.NewRequest("GET", u.String(), nil)
+	if err != nil {
+		return 0, "", err
+	}
+
+	req.Header.Set("User-Agent", c.useragent)
+
+	if c.username != "" {
+		req.SetBasicAuth(c.username, c.password)
+	}
+
+	if timeout > 0 {
+		params := req.URL.Query()
+		params.Set("wait_for_leader", fmt.Sprintf("%.0fs", timeout.Seconds()))
+		req.URL.RawQuery = params.Encode()
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return 0, "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return 0, "", err
+	}
+
+	if resp.StatusCode != http.StatusNoContent {
+		var err = fmt.Errorf(string(body))
+		return 0, "", err
+	}
+
+	version := resp.Header.Get("X-Influxdb-Version")
+	return time.Since(now), version, nil
+}
+
+// Close releases the client's resources.
+func (c *client) Close() error {
+	c.transport.CloseIdleConnections()
+	return nil
+}
+
+// client is safe for concurrent use as the fields are all read-only
+// once the client is instantiated.
+type client struct {
+	// N.B - if url.UserInfo is accessed in future modifications to the
+	// methods on client, you will need to syncronise access to url.
+	url        url.URL
+	username   string
+	password   string
+	useragent  string
+	httpClient *http.Client
+	transport  *http.Transport
+}
+
+// BatchPoints is an interface into a batched grouping of points to write into
+// InfluxDB together. BatchPoints is NOT thread-safe, you must create a separate
+// batch for each goroutine.
+type BatchPoints interface {
+	// AddPoint adds the given point to the Batch of points.
+	AddPoint(p *Point)
+	// AddPoints adds the given points to the Batch of points.
+	AddPoints(ps []*Point)
+	// Points lists the points in the Batch.
+	Points() []*Point
+
+	// Precision returns the currently set precision of this Batch.
+	Precision() string
+	// SetPrecision sets the precision of this batch.
+	SetPrecision(s string) error
+
+	// Database returns the currently set database of this Batch.
+	Database() string
+	// SetDatabase sets the database of this Batch.
+	SetDatabase(s string)
+
+	// WriteConsistency returns the currently set write consistency of this Batch.
+	WriteConsistency() string
+	// SetWriteConsistency sets the write consistency of this Batch.
+	SetWriteConsistency(s string)
+
+	// RetentionPolicy returns the currently set retention policy of this Batch.
+	RetentionPolicy() string
+	// SetRetentionPolicy sets the retention policy of this Batch.
+	SetRetentionPolicy(s string)
+}
+
+// NewBatchPoints returns a BatchPoints interface based on the given config.
+func NewBatchPoints(conf BatchPointsConfig) (BatchPoints, error) {
+	if conf.Precision == "" {
+		conf.Precision = "ns"
+	}
+	if _, err := time.ParseDuration("1" + conf.Precision); err != nil {
+		return nil, err
+	}
+	bp := &batchpoints{
+		database:         conf.Database,
+		precision:        conf.Precision,
+		retentionPolicy:  conf.RetentionPolicy,
+		writeConsistency: conf.WriteConsistency,
+	}
+	return bp, nil
+}
+
+type batchpoints struct {
+	points           []*Point
+	database         string
+	precision        string
+	retentionPolicy  string
+	writeConsistency string
+}
+
+func (bp *batchpoints) AddPoint(p *Point) {
+	bp.points = append(bp.points, p)
+}
+
+func (bp *batchpoints) AddPoints(ps []*Point) {
+	bp.points = append(bp.points, ps...)
+}
+
+func (bp *batchpoints) Points() []*Point {
+	return bp.points
+}
+
+func (bp *batchpoints) Precision() string {
+	return bp.precision
+}
+
+func (bp *batchpoints) Database() string {
+	return bp.database
+}
+
+func (bp *batchpoints) WriteConsistency() string {
+	return bp.writeConsistency
+}
+
+func (bp *batchpoints) RetentionPolicy() string {
+	return bp.retentionPolicy
+}
+
+func (bp *batchpoints) SetPrecision(p string) error {
+	if _, err := time.ParseDuration("1" + p); err != nil {
+		return err
+	}
+	bp.precision = p
+	return nil
+}
+
+func (bp *batchpoints) SetDatabase(db string) {
+	bp.database = db
+}
+
+func (bp *batchpoints) SetWriteConsistency(wc string) {
+	bp.writeConsistency = wc
+}
+
+func (bp *batchpoints) SetRetentionPolicy(rp string) {
+	bp.retentionPolicy = rp
+}
+
+// Point represents a single data point.
+type Point struct {
+	pt models.Point
+}
+
+// NewPoint returns a point with the given timestamp. If a timestamp is not
+// given, then data is sent to the database without a timestamp, in which case
+// the server will assign local time upon reception. NOTE: it is recommended to
+// send data with a timestamp.
+func NewPoint(
+	name string,
+	tags map[string]string,
+	fields map[string]interface{},
+	t ...time.Time,
+) (*Point, error) {
+	var T time.Time
+	if len(t) > 0 {
+		T = t[0]
+	}
+
+	pt, err := models.NewPoint(name, models.NewTags(tags), fields, T)
+	if err != nil {
+		return nil, err
+	}
+	return &Point{
+		pt: pt,
+	}, nil
+}
+
+// String returns a line-protocol string of the Point.
+func (p *Point) String() string {
+	return p.pt.String()
+}
+
+// PrecisionString returns a line-protocol string of the Point,
+// with the timestamp formatted for the given precision.
+func (p *Point) PrecisionString(precison string) string {
+	return p.pt.PrecisionString(precison)
+}
+
+// Name returns the measurement name of the point.
+func (p *Point) Name() string {
+	return string(p.pt.Name())
+}
+
+// Tags returns the tags associated with the point.
+func (p *Point) Tags() map[string]string {
+	return p.pt.Tags().Map()
+}
+
+// Time return the timestamp for the point.
+func (p *Point) Time() time.Time {
+	return p.pt.Time()
+}
+
+// UnixNano returns timestamp of the point in nanoseconds since Unix epoch.
+func (p *Point) UnixNano() int64 {
+	return p.pt.UnixNano()
+}
+
+// Fields returns the fields for the point.
+func (p *Point) Fields() (map[string]interface{}, error) {
+	return p.pt.Fields()
+}
+
+// NewPointFrom returns a point from the provided models.Point.
+func NewPointFrom(pt models.Point) *Point {
+	return &Point{pt: pt}
+}
+
+func (c *client) Write(bp BatchPoints) error {
+	var b bytes.Buffer
+
+	for _, p := range bp.Points() {
+		if _, err := b.WriteString(p.pt.PrecisionString(bp.Precision())); err != nil {
+			return err
+		}
+
+		if err := b.WriteByte('\n'); err != nil {
+			return err
+		}
+	}
+
+	u := c.url
+	u.Path = "write"
+	req, err := http.NewRequest("POST", u.String(), &b)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "")
+	req.Header.Set("User-Agent", c.useragent)
+	if c.username != "" {
+		req.SetBasicAuth(c.username, c.password)
+	}
+
+	params := req.URL.Query()
+	params.Set("db", bp.Database())
+	params.Set("rp", bp.RetentionPolicy())
+	params.Set("precision", bp.Precision())
+	params.Set("consistency", bp.WriteConsistency())
+	req.URL.RawQuery = params.Encode()
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != http.StatusNoContent && resp.StatusCode != http.StatusOK {
+		var err = fmt.Errorf(string(body))
+		return err
+	}
+
+	return nil
+}
+
+// Query defines a query to send to the server.
+type Query struct {
+	Command    string
+	Database   string
+	Precision  string
+	Chunked    bool
+	ChunkSize  int
+	Parameters map[string]interface{}
+}
+
+// NewQuery returns a query object.
+// The database and precision arguments can be empty strings if they are not needed for the query.
+func NewQuery(command, database, precision string) Query {
+	return Query{
+		Command:    command,
+		Database:   database,
+		Precision:  precision,
+		Parameters: make(map[string]interface{}),
+	}
+}
+
+// NewQueryWithParameters returns a query object.
+// The database and precision arguments can be empty strings if they are not needed for the query.
+// parameters is a map of the parameter names used in the command to their values.
+func NewQueryWithParameters(command, database, precision string, parameters map[string]interface{}) Query {
+	return Query{
+		Command:    command,
+		Database:   database,
+		Precision:  precision,
+		Parameters: parameters,
+	}
+}
+
+// Response represents a list of statement results.
+type Response struct {
+	Results []Result
+	Err     string `json:"error,omitempty"`
+}
+
+// Error returns the first error from any statement.
+// It returns nil if no errors occurred on any statements.
+func (r *Response) Error() error {
+	if r.Err != "" {
+		return fmt.Errorf(r.Err)
+	}
+	for _, result := range r.Results {
+		if result.Err != "" {
+			return fmt.Errorf(result.Err)
+		}
+	}
+	return nil
+}
+
+// Message represents a user message.
+type Message struct {
+	Level string
+	Text  string
+}
+
+// Result represents a resultset returned from a single statement.
+type Result struct {
+	Series   []models.Row
+	Messages []*Message
+	Err      string `json:"error,omitempty"`
+}
+
+// Query sends a command to the server and returns the Response.
+func (c *client) Query(q Query) (*Response, error) {
+	u := c.url
+	u.Path = "query"
+
+	jsonParameters, err := json.Marshal(q.Parameters)
+
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest("POST", u.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Type", "")
+	req.Header.Set("User-Agent", c.useragent)
+
+	if c.username != "" {
+		req.SetBasicAuth(c.username, c.password)
+	}
+
+	params := req.URL.Query()
+	params.Set("q", q.Command)
+	params.Set("db", q.Database)
+	params.Set("params", string(jsonParameters))
+	if q.Chunked {
+		params.Set("chunked", "true")
+		if q.ChunkSize > 0 {
+			params.Set("chunk_size", strconv.Itoa(q.ChunkSize))
+		}
+	}
+
+	if q.Precision != "" {
+		params.Set("epoch", q.Precision)
+	}
+	req.URL.RawQuery = params.Encode()
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	// If we lack a X-Influxdb-Version header, then we didn't get a response from influxdb
+	// but instead some other service. If the error code is also a 500+ code, then some
+	// downstream loadbalancer/proxy/etc had an issue and we should report that.
+	if resp.Header.Get("X-Influxdb-Version") == "" && resp.StatusCode >= http.StatusInternalServerError {
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil || len(body) == 0 {
+			return nil, fmt.Errorf("received status code %d from downstream server", resp.StatusCode)
+		}
+
+		return nil, fmt.Errorf("received status code %d from downstream server, with response body: %q", resp.StatusCode, body)
+	}
+
+	// If we get an unexpected content type, then it is also not from influx direct and therefore
+	// we want to know what we received and what status code was returned for debugging purposes.
+	if cType, _, _ := mime.ParseMediaType(resp.Header.Get("Content-Type")); cType != "application/json" {
+		// Read up to 1kb of the body to help identify downstream errors and limit the impact of things
+		// like downstream serving a large file
+		body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1024))
+		if err != nil || len(body) == 0 {
+			return nil, fmt.Errorf("expected json response, got empty body, with status: %v", resp.StatusCode)
+		}
+
+		return nil, fmt.Errorf("expected json response, got %q, with status: %v and response body: %q", cType, resp.StatusCode, body)
+	}
+
+	var response Response
+	if q.Chunked {
+		cr := NewChunkedResponse(resp.Body)
+		for {
+			r, err := cr.NextResponse()
+			if err != nil {
+				// If we got an error while decoding the response, send that back.
+				return nil, err
+			}
+
+			if r == nil {
+				break
+			}
+
+			response.Results = append(response.Results, r.Results...)
+			if r.Err != "" {
+				response.Err = r.Err
+				break
+			}
+		}
+	} else {
+		dec := json.NewDecoder(resp.Body)
+		dec.UseNumber()
+		decErr := dec.Decode(&response)
+
+		// ignore this error if we got an invalid status code
+		if decErr != nil && decErr.Error() == "EOF" && resp.StatusCode != http.StatusOK {
+			decErr = nil
+		}
+		// If we got a valid decode error, send that back
+		if decErr != nil {
+			return nil, fmt.Errorf("unable to decode json: received status code %d err: %s", resp.StatusCode, decErr)
+		}
+	}
+
+	// If we don't have an error in our json response, and didn't get statusOK
+	// then send back an error
+	if resp.StatusCode != http.StatusOK && response.Error() == nil {
+		return &response, fmt.Errorf("received status code %d from server", resp.StatusCode)
+	}
+	return &response, nil
+}
+
+// duplexReader reads responses and writes it to another writer while
+// satisfying the reader interface.
+type duplexReader struct {
+	r io.Reader
+	w io.Writer
+}
+
+func (r *duplexReader) Read(p []byte) (n int, err error) {
+	n, err = r.r.Read(p)
+	if err == nil {
+		r.w.Write(p[:n])
+	}
+	return n, err
+}
+
+// ChunkedResponse represents a response from the server that
+// uses chunking to stream the output.
+type ChunkedResponse struct {
+	dec    *json.Decoder
+	duplex *duplexReader
+	buf    bytes.Buffer
+}
+
+// NewChunkedResponse reads a stream and produces responses from the stream.
+func NewChunkedResponse(r io.Reader) *ChunkedResponse {
+	resp := &ChunkedResponse{}
+	resp.duplex = &duplexReader{r: r, w: &resp.buf}
+	resp.dec = json.NewDecoder(resp.duplex)
+	resp.dec.UseNumber()
+	return resp
+}
+
+// NextResponse reads the next line of the stream and returns a response.
+func (r *ChunkedResponse) NextResponse() (*Response, error) {
+	var response Response
+
+	if err := r.dec.Decode(&response); err != nil {
+		if err == io.EOF {
+			return nil, nil
+		}
+		// A decoding error happened. This probably means the server crashed
+		// and sent a last-ditch error message to us. Ensure we have read the
+		// entirety of the connection to get any remaining error text.
+		io.Copy(ioutil.Discard, r.duplex)
+		return nil, errors.New(strings.TrimSpace(r.buf.String()))
+	}
+
+	r.buf.Reset()
+	return &response, nil
+}
diff --git a/vendor/github.com/influxdata/influxdb/client/v2/udp.go b/vendor/github.com/influxdata/influxdb/client/v2/udp.go
new file mode 100644
index 000000000..779a28b33
--- /dev/null
+++ b/vendor/github.com/influxdata/influxdb/client/v2/udp.go
@@ -0,0 +1,112 @@
+package client
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"time"
+)
+
+const (
+	// UDPPayloadSize is a reasonable default payload size for UDP packets that
+	// could be travelling over the internet.
+	UDPPayloadSize = 512
+)
+
+// UDPConfig is the config data needed to create a UDP Client.
+type UDPConfig struct {
+	// Addr should be of the form "host:port"
+	// or "[ipv6-host%zone]:port".
+	Addr string
+
+	// PayloadSize is the maximum size of a UDP client message, optional
+	// Tune this based on your network. Defaults to UDPPayloadSize.
+	PayloadSize int
+}
+
+// NewUDPClient returns a client interface for writing to an InfluxDB UDP
+// service from the given config.
+func NewUDPClient(conf UDPConfig) (Client, error) {
+	var udpAddr *net.UDPAddr
+	udpAddr, err := net.ResolveUDPAddr("udp", conf.Addr)
+	if err != nil {
+		return nil, err
+	}
+
+	conn, err := net.DialUDP("udp", nil, udpAddr)
+	if err != nil {
+		return nil, err
+	}
+
+	payloadSize := conf.PayloadSize
+	if payloadSize == 0 {
+		payloadSize = UDPPayloadSize
+	}
+
+	return &udpclient{
+		conn:        conn,
+		payloadSize: payloadSize,
+	}, nil
+}
+
+// Close releases the udpclient's resources.
+func (uc *udpclient) Close() error {
+	return uc.conn.Close()
+}
+
+type udpclient struct {
+	conn        io.WriteCloser
+	payloadSize int
+}
+
+func (uc *udpclient) Write(bp BatchPoints) error {
+	var b = make([]byte, 0, uc.payloadSize) // initial buffer size, it will grow as needed
+	var d, _ = time.ParseDuration("1" + bp.Precision())
+
+	var delayedError error
+
+	var checkBuffer = func(n int) {
+		if len(b) > 0 && len(b)+n > uc.payloadSize {
+			if _, err := uc.conn.Write(b); err != nil {
+				delayedError = err
+			}
+			b = b[:0]
+		}
+	}
+
+	for _, p := range bp.Points() {
+		p.pt.Round(d)
+		pointSize := p.pt.StringSize() + 1 // include newline in size
+		//point := p.pt.RoundedString(d) + "\n"
+
+		checkBuffer(pointSize)
+
+		if p.Time().IsZero() || pointSize <= uc.payloadSize {
+			b = p.pt.AppendString(b)
+			b = append(b, '\n')
+			continue
+		}
+
+		points := p.pt.Split(uc.payloadSize - 1) // account for newline character
+		for _, sp := range points {
+			checkBuffer(sp.StringSize() + 1)
+			b = sp.AppendString(b)
+			b = append(b, '\n')
+		}
+	}
+
+	if len(b) > 0 {
+		if _, err := uc.conn.Write(b); err != nil {
+			return err
+		}
+	}
+	return delayedError
+}
+
+func (uc *udpclient) Query(q Query) (*Response, error) {
+	return nil, fmt.Errorf("Querying via UDP is not supported")
+}
+
+func (uc *udpclient) Ping(timeout time.Duration) (time.Duration, string, error) {
+	return 0, "", nil
+}