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k8s middleware cleanup, testcases, basic SRV (#181)

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* Removing unnecessary gitignore pattern

* Updating Makefile to run unittests for subpackages

* Adding Corefile validation to ignore overlapping zones

* Fixing SRV query handling

* Updating README.md now that SRV works

* Fixing debug message, adding code comment

* Clarifying implementation of zone normalization

* "Overlapping zones" is ill-defined. Reimplemented zone overlap/subzone
  checking to contain these functions in k8s middleware and provide
  better code comments explaining the normalization.

* Separate build verbosity from test verbosity

* Cleaning up comments to match repo code style

* Merging warning messages into single message
* Moving function docs to before function declaration

* Adding test cases for k8sclient connector

* Tests cover connector create and setting base url
* Fixed bugs in connector create and setting base url functions

* Updaing README to group and order development work

* Priority focused on achieving functional parity with SkyDNS.

* Adding work items to README and cleaning up formatting

* More README format cleaning

* List formating

* Refactoring k8s API call to allow dependency injection

* Add test cases for data parsing from k8s into dataobject structures

* URL is dependency-injected to allow replacement with a mock http
  server during test execution

* Adding more data validation for JSON parsing tests

* Adding test case for GetResourceList()

* Adding notes about SkyDNS embedded IP and port record names

* Marked test case implemented.

* Fixing formatting for example command.

* Fixing formatting

* Adding notes about Docker image building.

* Adding SkyDNS work item

* Updating TODO list

* Adding name template to Corefile to specify how k8s record names are assembled

* Adding template support for multi-segment zones

* Updating example CoreFile for k8s with template comment

* Misc whitespace cleanup

* Adding SkyDNS naming notes

* Adding namespace filtering to CoreFile config

* Updating example k8sCoreFile to specify namespaces

* Removing unused codepath

* Adding check for valid namespace

* More README TODO restructuring to focus effort

* Adding template validation while parsing CoreFile

* Record name template is considered invalid if it contains a symbol of the form ${bar} where the symbol
  "${bar}" is not an accepted template symbol.

* Refactoring generation of answer records

* Parse typeName out of query string
* Refactor answer record creation as operation over list of ServiceItems

* Moving k8s API caching into SkyDNS equivalency segment

* Adding function to assemble record names from template

* Warning: This commit may be broken. Syncing to get laptop code over to dev machine.

* More todo notes

* Adding comment describing sample test data.

* Update k8sCorefile

* Adding comment

* Adding filtering support for kubernetes "type"

* Required refactoring to support reuse of the StringInSlice function.

* Cleaning up formatting

* Adding note about SkyDNS supporting word "any".

* baseUrl -> baseURL

* Also removed debug statement from core/setup/kubernetes.go

* Fixing test breaking from Url -> URL naming changes

* Changing record name template language ${...} -> {...}

* Fix formatting with go fmt

* Updating all k8sclient data getters to return error value

* Adding error message to k8sclient data accessors

* Cleaning up setup for kubernetes

* Removed verbose nils in initial k8s middleware instance
* Set reasonable defaults if CoreFile has no parameters in the
kubernetes block. (k8s endpoint, and name template)

* Formatting cleanup -- go fmt
This commit is contained in:
Michael Richmond 2016-07-07 01:40:58 -07:00 • committed by Miek Gieben
parent 558c34a23e
commit 289f53d386
19 changed files with 1610 additions and 304 deletions
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197
middleware/kubernetes/kubernetes.go
View file

@ -2,111 +2,148 @@
package kubernetes
import (
"fmt"
"strings"
"errors"
"fmt"
"time"
"github.com/miekg/coredns/middleware"
"github.com/miekg/coredns/middleware/kubernetes/msg"
k8sc "github.com/miekg/coredns/middleware/kubernetes/k8sclient"
"github.com/miekg/coredns/middleware/kubernetes/msg"
"github.com/miekg/coredns/middleware/kubernetes/nametemplate"
"github.com/miekg/coredns/middleware/kubernetes/util"
"github.com/miekg/coredns/middleware/proxy"
// "github.com/miekg/coredns/middleware/singleflight"
// "github.com/miekg/coredns/middleware/singleflight"
"github.com/miekg/dns"
"github.com/miekg/dns"
"golang.org/x/net/context"
)
type Kubernetes struct {
Next middleware.Handler
Zones []string
Proxy proxy.Proxy // Proxy for looking up names during the resolution process
Ctx context.Context
// Inflight *singleflight.Group
APIConn *k8sc.K8sConnector
Next middleware.Handler
Zones []string
Proxy proxy.Proxy // Proxy for looking up names during the resolution process
Ctx context.Context
// Inflight *singleflight.Group
APIConn *k8sc.K8sConnector
NameTemplate *nametemplate.NameTemplate
Namespaces *[]string
}
// getZoneForName returns the zone string that matches the name and a
// list of the DNS labels from name that are within the zone.
// For example, if "coredns.local" is a zone configured for the
// Kubernetes middleware, then getZoneForName("a.b.coredns.local")
// will return ("coredns.local", ["a", "b"]).
func (g Kubernetes) getZoneForName(name string) (string, []string) {
/*
* getZoneForName returns the zone string that matches the name and a
* list of the DNS labels from name that are within the zone.
* For example, if "coredns.local" is a zone configured for the
* Kubernetes middleware, then getZoneForName("a.b.coredns.local")
* will return ("coredns.local", ["a", "b"]).
*/
var zone string
var serviceSegments []string
var zone string
var serviceSegments []string
for _, z := range g.Zones {
if dns.IsSubDomain(z, name) {
zone = z
serviceSegments = dns.SplitDomainName(name)
serviceSegments = serviceSegments[:len(serviceSegments) - dns.CountLabel(zone)]
break
}
}
for _, z := range g.Zones {
if dns.IsSubDomain(z, name) {
zone = z
return zone, serviceSegments
}
serviceSegments = dns.SplitDomainName(name)
serviceSegments = serviceSegments[:len(serviceSegments)-dns.CountLabel(zone)]
break
}
}
return zone, serviceSegments
}
// Records looks up services in kubernetes.
// If exact is true, it will lookup just
// this name. This is used when find matches when completing SRV lookups
// for instance.
func (g Kubernetes) Records(name string, exact bool) ([]msg.Service, error) {
var (
serviceName string
namespace string
typeName string
)
fmt.Println("enter Records('", name, "', ", exact, ")")
fmt.Println("enter Records('", name, "', ", exact, ")")
zone, serviceSegments := g.getZoneForName(name)
zone, serviceSegments := g.getZoneForName(name)
/*
// For initial implementation, assume namespace is first serviceSegment
// and service name is remaining segments.
serviceSegLen := len(serviceSegments)
if serviceSegLen >= 2 {
namespace = serviceSegments[serviceSegLen-1]
serviceName = strings.Join(serviceSegments[:serviceSegLen-1], ".")
}
// else we are looking up the zone. So handle the NS, SOA records etc.
*/
var serviceName string
var namespace string
// TODO: Implementation above globbed together segments for the serviceName if
// multiple segments remained. Determine how to do similar globbing using
// the template-based implementation.
namespace = g.NameTemplate.GetNamespaceFromSegmentArray(serviceSegments)
serviceName = g.NameTemplate.GetServiceFromSegmentArray(serviceSegments)
typeName = g.NameTemplate.GetTypeFromSegmentArray(serviceSegments)
// For initial implementation, assume namespace is first serviceSegment
// and service name is remaining segments.
serviceSegLen := len(serviceSegments)
if serviceSegLen >= 2 {
namespace = serviceSegments[serviceSegLen-1]
serviceName = strings.Join(serviceSegments[:serviceSegLen-1], ".")
}
// else we are looking up the zone. So handle the NS, SOA records etc.
fmt.Println("[debug] exact: ", exact)
fmt.Println("[debug] zone: ", zone)
fmt.Println("[debug] servicename: ", serviceName)
fmt.Println("[debug] namespace: ", namespace)
fmt.Println("[debug] typeName: ", typeName)
fmt.Println("[debug] APIconn: ", g.APIConn)
fmt.Println("[debug] zone: ", zone)
fmt.Println("[debug] servicename: ", serviceName)
fmt.Println("[debug] namespace: ", namespace)
fmt.Println("[debug] APIconn: ", g.APIConn)
// TODO: Implement wildcard support to allow blank namespace value
if namespace == "" {
err := errors.New("Parsing query string did not produce a namespace value")
fmt.Printf("[ERROR] %v\n", err)
return nil, err
}
k8sItem := g.APIConn.GetServiceItemInNamespace(namespace, serviceName)
fmt.Println("[debug] k8s item:", k8sItem)
// Abort if the namespace is not published per CoreFile
if g.Namespaces != nil && !util.StringInSlice(namespace, *g.Namespaces) {
return nil, nil
}
switch {
case exact && k8sItem == nil:
fmt.Println("here2")
return nil, nil
}
k8sItems, err := g.APIConn.GetServiceItemsInNamespace(namespace, serviceName)
fmt.Println("[debug] k8s items:", k8sItems)
if k8sItem == nil {
// Did not find item in k8s
return nil, nil
}
if err != nil {
fmt.Printf("[ERROR] Got error while looking up ServiceItems. Error is: %v\n", err)
return nil, err
}
if k8sItems == nil {
// Did not find item in k8s
return nil, nil
}
fmt.Println("[debug] clusterIP:", k8sItem.Spec.ClusterIP)
// test := g.NameTemplate.GetRecordNameFromNameValues(nametemplate.NameValues{ServiceName: serviceName, TypeName: typeName, Namespace: namespace, Zone: zone})
// fmt.Printf("[debug] got recordname %v\n", test)
for _, p := range k8sItem.Spec.Ports {
fmt.Println("[debug] host:", name)
fmt.Println("[debug] port:", p.Port)
}
records := g.getRecordsForServiceItems(k8sItems, name)
clusterIP := k8sItem.Spec.ClusterIP
var records []msg.Service
for _, p := range k8sItem.Spec.Ports{
s := msg.Service{Host: clusterIP, Port: p.Port}
records = append(records, s)
}
return records, nil
}
return records, nil
// TODO: assemble name from parts found in k8s data based on name template rather than reusing query string
func (g Kubernetes) getRecordsForServiceItems(serviceItems []*k8sc.ServiceItem, name string) []msg.Service {
var records []msg.Service
for _, item := range serviceItems {
fmt.Println("[debug] clusterIP:", item.Spec.ClusterIP)
for _, p := range item.Spec.Ports {
fmt.Println("[debug] port:", p.Port)
}
clusterIP := item.Spec.ClusterIP
s := msg.Service{Host: name}
records = append(records, s)
for _, p := range item.Spec.Ports {
s := msg.Service{Host: clusterIP, Port: p.Port}
records = append(records, s)
}
}
fmt.Printf("[debug] records from getRecordsForServiceItems(): %v\n", records)
return records
}
/*
@ -121,13 +158,13 @@ func (g Kubernetes) Get(path string, recursive bool) (bool, error) {
*/
func (g Kubernetes) splitDNSName(name string) []string {
l := dns.SplitDomainName(name)
l := dns.SplitDomainName(name)
for i, j := 0, len(l)-1; i < j; i, j = i+1, j-1 {
l[i], l[j] = l[j], l[i]
}
for i, j := 0, len(l)-1; i < j; i, j = i+1, j-1 {
l[i], l[j] = l[j], l[i]
}
return l
return l
}
// skydns/local/skydns/east/staging/web
@ -215,9 +252,9 @@ func isKubernetesNameError(err error) bool {
}
const (
priority = 10 // default priority when nothing is set
ttl = 300 // default ttl when nothing is set
minTtl = 60
hostmaster = "hostmaster"
priority = 10 // default priority when nothing is set
ttl = 300 // default ttl when nothing is set
minTtl = 60
hostmaster = "hostmaster"
k8sTimeout = 5 * time.Second
)