client_golang/tutorial/whatsup/internal/common.go

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// Copyright 2023 The Prometheus Authors
// 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 internal
import (
"flag"
"fmt"
"net"
"os"
"strings"
"gopkg.in/yaml.v2"
)
const WhatsupPort = "99"
var (
WhatsAppFlags = flag.NewFlagSet("whatsapp", flag.ExitOnError)
prometheusAddr = WhatsAppFlags.String("prometheus-address", "", "The address of Prometheus to query.")
traceEndpoint = WhatsAppFlags.String("trace-endpoint", "", "Optional GRPC OTLP endpoint for tracing backend. Set it to 'stdout' to print traces to the output instead.")
traceSamplingRatio = WhatsAppFlags.Float64("trace-sampling-ratio", 1.0, "Sampling ratio. Currently 1.0 is the best value to use with exemplars.")
configFile = WhatsAppFlags.String("config-file", "./whatsup.yaml", "YAML configuration with same options as flags here. Flags override the configuration items.")
)
type Config struct {
PrometheusAddr string `yaml:"PrometheusAddress,omitempty"`
TraceEndpoint string `yaml:"TraceEndpoint,omitempty"`
TraceSamplingRatio float64 `yaml:"TraceSamplingRatio,omitempty"`
}
func isWSL() bool {
b, err := os.ReadFile("/proc/version")
if err != nil {
return false
}
if strings.Contains(string(b), "WSL") {
return true
}
return false
}
func getInterfaceIpv4Addr(interfaceName string) (addr string, err error) {
var (
ief *net.Interface
addrs []net.Addr
ipv4Addr net.IP
)
if ief, err = net.InterfaceByName(interfaceName); err != nil {
return "", err
}
if addrs, err = ief.Addrs(); err != nil {
return "", err
}
for _, addr := range addrs {
if ipv4Addr = addr.(*net.IPNet).IP.To4(); ipv4Addr != nil {
break
}
}
if ipv4Addr == nil {
return "", fmt.Errorf("interface %s does not have an ipv4 address", interfaceName)
}
return ipv4Addr.String(), nil
}
func whatsupAddr(defAddress string) string {
if a := os.Getenv("HOSTADDR"); a != "" {
return a + ":" + WhatsupPort
}
// use eth0 IP address if running WSL, return default if check fails
if isWSL() {
a, err := getInterfaceIpv4Addr("eth0")
if err != nil {
return defAddress
}
return a + ":" + WhatsupPort
}
return defAddress
}
func ParseOptions(args []string) (Config, error) {
c := Config{}
if err := WhatsAppFlags.Parse(args); err != nil {
return c, err
}
if *configFile != "" {
b, err := os.ReadFile(*configFile)
if err != nil {
return c, err
}
if err := yaml.Unmarshal(b, &c); err != nil {
return c, err
}
}
if *prometheusAddr != "" {
c.PrometheusAddr = *prometheusAddr
}
if *traceEndpoint != "" {
c.TraceEndpoint = *traceEndpoint
}
if *traceSamplingRatio > 0 {
c.TraceSamplingRatio = *traceSamplingRatio
}
return c, nil
}