f96cf27193
* mw/federaration This PR add the federation back as a middleware to keep it more contained from the main kubernetes code. It also makes parseRequest less import and pushes this functionlity down in the k.Entries. This minimizes (or tries to) the importance for the qtype in the query. In the end the qtype checking should only happen in ServeDNS - but for k8s this might proof difficult. Numerous other cleanup in code and kubernetes tests. * up test coverage
106 lines
2.9 KiB
Go
106 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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service string
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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. This value is true for
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// pods and false for services. If we ever need to extend this well use a typed value.
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podOrSvc string
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zone string
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}
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// parseRequest parses the qname to find all the elements we need for querying k8s.
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func (k *Kubernetes) parseRequest(state request.Request) (r recordRequest, err error) {
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// 3 Possible cases:
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// o SRV Request: _port._protocol.service.namespace.type.zone
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// o A Request (endpoint): endpoint.service.namespace.type.zone
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// o A Request (service): service.namespace.type.zone
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// Federations are handled in the federation middleware.
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base, _ := dnsutil.TrimZone(state.Name(), state.Zone)
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segs := dns.SplitDomainName(base)
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r.zone = state.Zone
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offset := 0
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if state.QType() == dns.TypeSRV {
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// The kubernetes peer-finder expects queries with empty port and service to resolve
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// If neither is specified, treat it as a wildcard
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if len(segs) == 3 {
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r.port = "*"
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r.service = "*"
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offset = 0
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} else {
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if len(segs) != 5 {
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return r, errInvalidRequest
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}
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// This is a SRV style request, get first two elements as port and
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// protocol, stripping leading underscores if present.
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if segs[0][0] == '_' {
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r.port = segs[0][1:]
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} else {
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r.port = segs[0]
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if !wildcard(r.port) {
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return r, errInvalidRequest
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}
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}
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if segs[1][0] == '_' {
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r.protocol = segs[1][1:]
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if r.protocol != "tcp" && r.protocol != "udp" {
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return r, errInvalidRequest
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}
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} else {
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r.protocol = segs[1]
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if !wildcard(r.protocol) {
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return r, errInvalidRequest
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}
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}
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if r.port == "" || r.protocol == "" {
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return r, errInvalidRequest
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}
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offset = 2
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}
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}
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if (state.QType() == dns.TypeA || state.QType() == dns.TypeAAAA) && len(segs) == 4 {
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// This is an endpoint A/AAAA record request. Get first element as endpoint.
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r.endpoint = segs[0]
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offset = 1
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}
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if len(segs) == (offset + 3) {
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r.service = segs[offset]
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r.namespace = segs[offset+1]
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r.podOrSvc = segs[offset+2]
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return r, nil
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}
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return r, errInvalidRequest
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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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s += "." + r.zone
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return s
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}
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