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|
package trace
import (
"fmt"
"strconv"
"strings"
"github.com/coredns/caddy"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/plugin"
)
func init() { plugin.Register("trace", 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{every: 1, serviceName: defServiceName}
err error
)
cfg := dnsserver.GetConfig(c)
if cfg.ListenHosts[0] != "" {
tr.serviceEndpoint = cfg.ListenHosts[0] + ":" + cfg.Port
}
for c.Next() { // trace
var err error
args := c.RemainingArgs()
switch len(args) {
case 0:
tr.EndpointType, tr.Endpoint, err = normalizeEndpoint(defEpType, "")
case 1:
tr.EndpointType, tr.Endpoint, err = normalizeEndpoint(defEpType, args[0])
case 2:
epType := strings.ToLower(args[0])
tr.EndpointType, tr.Endpoint, err = normalizeEndpoint(epType, 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
}
case "datadog_analytics_rate":
args := c.RemainingArgs()
if len(args) > 1 {
return nil, c.ArgErr()
}
tr.datadogAnalyticsRate = 0
if len(args) == 1 {
tr.datadogAnalyticsRate, err = strconv.ParseFloat(args[0], 64)
}
if err != nil {
return nil, err
}
if tr.datadogAnalyticsRate > 1 || tr.datadogAnalyticsRate < 0 {
return nil, fmt.Errorf("datadog analytics rate must be between 0 and 1, '%f' is not supported", tr.datadogAnalyticsRate)
}
}
}
}
return tr, err
}
func normalizeEndpoint(epType, ep string) (string, string, error) {
if _, ok := supportedProviders[epType]; !ok {
return "", "", fmt.Errorf("tracing endpoint type '%s' is not supported", epType)
}
if ep == "" {
ep = supportedProviders[epType]
}
if epType == "zipkin" {
if !strings.Contains(ep, "http") {
ep = "http://" + ep + "/api/v2/spans"
}
}
return epType, ep, nil
}
var supportedProviders = map[string]string{
"zipkin": "localhost:9411",
"datadog": "localhost:8126",
}
const (
defEpType = "zipkin"
defServiceName = "coredns"
)
|
