9e9d72655d
Make middleware that sets up a (http) handler survive a graceful restart. We calls the middleware's Shutdown function(s). If restart fails the Start function is called again. * middleware/health: OK * middleware/pprof: OK * middleware/metrics: OK All restart OK.
72 lines
1.4 KiB
Go
72 lines
1.4 KiB
Go
package setup
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import (
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"sync"
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"github.com/miekg/coredns/middleware"
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"github.com/miekg/coredns/middleware/metrics"
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)
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const addr = "localhost:9153"
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var metricsOnce sync.Once
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func Prometheus(c *Controller) (middleware.Middleware, error) {
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m, err := parsePrometheus(c)
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if err != nil {
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return nil, err
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}
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metricsOnce.Do(func() {
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c.Startup = append(c.Startup, m.Start)
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c.Shutdown = append(c.Shutdown, m.Shutdown)
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})
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return func(next middleware.Handler) middleware.Handler {
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m.Next = next
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return m
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}, nil
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}
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func parsePrometheus(c *Controller) (metrics.Metrics, error) {
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var (
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met metrics.Metrics
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err error
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)
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for c.Next() {
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if len(met.ZoneNames) > 0 {
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return metrics.Metrics{}, c.Err("metrics: can only have one metrics module per server")
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}
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met = metrics.Metrics{ZoneNames: c.ServerBlockHosts}
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for i, _ := range met.ZoneNames {
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met.ZoneNames[i] = middleware.Host(met.ZoneNames[i]).Normalize()
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}
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args := c.RemainingArgs()
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switch len(args) {
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case 0:
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case 1:
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met.Addr = args[0]
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default:
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return metrics.Metrics{}, c.ArgErr()
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}
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for c.NextBlock() {
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switch c.Val() {
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case "address":
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args = c.RemainingArgs()
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if len(args) != 1 {
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return metrics.Metrics{}, c.ArgErr()
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}
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met.Addr = args[0]
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default:
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return metrics.Metrics{}, c.Errf("metrics: unknown item: %s", c.Val())
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}
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}
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}
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if met.Addr == "" {
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met.Addr = addr
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}
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return met, err
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}
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