swarm: integrate OpenTracing; propagate ctx to internal APIs (#17169)

* swarm: propagate ctx, enable opentracing

* swarm/tracing: log error when tracing is misconfigured

vendor/github.com/uber/jaeger-client-go/utils/utils.go

@@ -0,0 +1,87 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package utils
+
+import (
+	"encoding/binary"
+	"errors"
+	"net"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	// ErrEmptyIP an error for empty ip strings
+	ErrEmptyIP = errors.New("empty string given for ip")
+
+	// ErrNotHostColonPort an error for invalid host port string
+	ErrNotHostColonPort = errors.New("expecting host:port")
+
+	// ErrNotFourOctets an error for the wrong number of octets after splitting a string
+	ErrNotFourOctets = errors.New("Wrong number of octets")
+)
+
+// ParseIPToUint32 converts a string ip (e.g. "x.y.z.w") to an uint32
+func ParseIPToUint32(ip string) (uint32, error) {
+	if ip == "" {
+		return 0, ErrEmptyIP
+	}
+
+	if ip == "localhost" {
+		return 127<<24 | 1, nil
+	}
+
+	octets := strings.Split(ip, ".")
+	if len(octets) != 4 {
+		return 0, ErrNotFourOctets
+	}
+
+	var intIP uint32
+	for i := 0; i < 4; i++ {
+		octet, err := strconv.Atoi(octets[i])
+		if err != nil {
+			return 0, err
+		}
+		intIP = (intIP << 8) | uint32(octet)
+	}
+
+	return intIP, nil
+}
+
+// ParsePort converts port number from string to uin16
+func ParsePort(portString string) (uint16, error) {
+	port, err := strconv.ParseUint(portString, 10, 16)
+	return uint16(port), err
+}
+
+// PackIPAsUint32 packs an IPv4 as uint32
+func PackIPAsUint32(ip net.IP) uint32 {
+	if ipv4 := ip.To4(); ipv4 != nil {
+		return binary.BigEndian.Uint32(ipv4)
+	}
+	return 0
+}
+
+// TimeToMicrosecondsSinceEpochInt64 converts Go time.Time to a long
+// representing time since epoch in microseconds, which is used expected
+// in the Jaeger spans encoded as Thrift.
+func TimeToMicrosecondsSinceEpochInt64(t time.Time) int64 {
+	// ^^^ Passing time.Time by value is faster than passing a pointer!
+	// BenchmarkTimeByValue-8	2000000000	         1.37 ns/op
+	// BenchmarkTimeByPtr-8  	2000000000	         1.98 ns/op
+
+	return t.UnixNano() / 1000
+}