aacb91ef0b
Remove the intermediate step of gathering everyhing in a kPod and kService and extracting the msg.Service from there. Now findPods and findServices return []msg.Service. This cuts down on the code and also removed the double looping of finding the data we need, so it should be faster.
109 lines
2.9 KiB
Go
109 lines
2.9 KiB
Go
package kubernetes
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import (
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"github.com/coredns/coredns/middleware/pkg/dnsutil"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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type recordRequest struct {
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// The named port from the kubernetes DNS spec, this is the service part (think _https) from a well formed
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// SRV record.
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port string
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// The protocol is usually _udp or _tcp (if set), and comes from the protocol part of a well formed
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// SRV record.
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protocol string
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endpoint string
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// The servicename used in Kubernetes.
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service string
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// The namespace used in Kubernetes.
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namespace string
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// A each name can be for a pod or a service, here we track what we've seen, either "pod" or "service".
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podOrSvc string
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}
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// parseRequest parses the qname to find all the elements we need for querying k8s. Anything
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// that is not parsed will have the wildcard "*" value (except r.endpoint).
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// Potential underscores are stripped from _port and _protocol.
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func parseRequest(state request.Request) (r recordRequest, err error) {
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// 3 Possible cases:
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// 1. _port._protocol.service.namespace.pod|svc.zone
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// 2. (endpoint): endpoint.service.namespace.pod|svc.zone
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// 3. (service): service.namespace.pod|svc.zone
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//
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// Federations are handled in the federation middleware. And aren't parsed here.
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base, _ := dnsutil.TrimZone(state.Name(), state.Zone)
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segs := dns.SplitDomainName(base)
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r.port = "*"
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r.protocol = "*"
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r.service = "*"
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r.namespace = "*"
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// r.endpoint is the odd one out, we need to know if it has been set or not. If it is
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// empty we should skip the endpoint check in k.get(). Hence we cannot set if to "*".
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// start at the right and fill out recordRequest with the bits we find, so we look for
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// pod|svc.namespace.service and then either
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// * endpoint
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// *_protocol._port
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last := len(segs) - 1
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r.podOrSvc = segs[last]
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if r.podOrSvc != Pod && r.podOrSvc != Svc {
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return r, errInvalidRequest
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}
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last--
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if last < 0 {
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return r, nil
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}
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r.namespace = segs[last]
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last--
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if last < 0 {
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return r, nil
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}
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r.service = segs[last]
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last--
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if last < 0 {
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return r, nil
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}
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// Becuase of ambiquity we check the labels left: 1: an endpoint. 2: port and protocol.
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// Anything else is a query that is too long to answer and can safely be delegated to return an nxdomain.
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switch last {
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case 0: // endpoint only
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r.endpoint = segs[last]
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case 1: // service and port
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r.protocol = stripUnderscore(segs[last])
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r.port = stripUnderscore(segs[last-1])
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default: // too long
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return r, errInvalidRequest
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}
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return r, nil
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}
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// stripUnderscore removes a prefixed underscore from s.
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func stripUnderscore(s string) string {
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if s[0] != '_' {
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return s
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}
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return s[1:]
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}
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// String return a string representation of r, it just returns all fields concatenated with dots.
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// This is mostly used in tests.
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func (r recordRequest) String() string {
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s := r.port
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s += "." + r.protocol
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s += "." + r.endpoint
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s += "." + r.service
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s += "." + r.namespace
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s += "." + r.podOrSvc
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return s
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}
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