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package trace
import (
"fmt"
"strconv"
"strings"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/plugin"
"github.com/mholt/caddy"
)
func init() {
caddy.RegisterPlugin("trace", caddy.Plugin{
ServerType: "dns",
Action: setup,
})
}
func setup(c *caddy.Controller) error {
t, err := traceParse(c)
if err != nil {
return plugin.Error("trace", err)
}
dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
t.Next = next
return t
})
c.OnStartup(t.OnStartup)
return nil
}
func traceParse(c *caddy.Controller) (*trace, error) {
var (
tr = &trace{Endpoint: defEP, EndpointType: defEpType, every: 1, serviceName: defServiceName}
err error
)
cfg := dnsserver.GetConfig(c)
tr.ServiceEndpoint = cfg.ListenHost + ":" + cfg.Port
for c.Next() { // trace
var err error
args := c.RemainingArgs()
switch len(args) {
case 0:
tr.Endpoint, err = normalizeEndpoint(tr.EndpointType, defEP)
case 1:
tr.Endpoint, err = normalizeEndpoint(defEpType, args[0])
case 2:
tr.EndpointType = strings.ToLower(args[0])
tr.Endpoint, err = normalizeEndpoint(tr.EndpointType, args[1])
default:
err = c.ArgErr()
}
if err != nil {
return tr, err
}
for c.NextBlock() {
switch c.Val() {
case "every":
args := c.RemainingArgs()
if len(args) != 1 {
return nil, c.ArgErr()
}
tr.every, err = strconv.ParseUint(args[0], 10, 64)
if err != nil {
return nil, err
}
case "service":
args := c.RemainingArgs()
if len(args) != 1 {
return nil, c.ArgErr()
}
tr.serviceName = args[0]
case "client_server":
args := c.RemainingArgs()
if len(args) > 1 {
return nil, c.ArgErr()
}
tr.clientServer = true
if len(args) == 1 {
tr.clientServer, err = strconv.ParseBool(args[0])
}
if err != nil {
return nil, err
}
}
}
}
return tr, err
}
func normalizeEndpoint(epType, ep string) (string, error) {
switch epType {
case "zipkin":
if !strings.Contains(ep, "http") {
ep = "http://" + ep + "/api/v1/spans"
}
return ep, nil
default:
return "", fmt.Errorf("tracing endpoint type '%s' is not supported", epType)
}
}
const (
defEP = "localhost:9411"
defEpType = "zipkin"
defServiceName = "coredns"
)
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