middleware

package
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 Go to latest Published: Sep 11, 2017 License: Apache-2.0 Imports: 13 Imported by: 0

Documentation

Overview

Package middleware provides some types and functions common among middleware.

Index

Constants

View Source 
const (
	TransportDNS  = "dns"
	TransportTLS  = "tls"
	TransportGRPC = "grpc"
)

Duplicated from core/dnsserver/address.go !

View Source 
const Namespace = "coredns"

Namespace is the namespace used for the metrics.

Variables

This section is empty.

Functions

func A 

func A(b ServiceBackend, zone string, state request.Request, previousRecords []dns.RR, opt Options) (records []dns.RR, debug []msg.Service, err error)

A returns A records from Backend or an error.

func AAAA 

func AAAA(b ServiceBackend, zone string, state request.Request, previousRecords []dns.RR, opt Options) (records []dns.RR, debug []msg.Service, err error)

AAAA returns AAAA records from Backend or an error.

func BackendError 

func BackendError(b ServiceBackend, zone string, rcode int, state request.Request, debug []msg.Service, err error, opt Options) (int, error)

BackendError writes an error response to the client.

func CNAME 

func CNAME(b ServiceBackend, zone string, state request.Request, opt Options) (records []dns.RR, debug []msg.Service, err error)

CNAME returns CNAME records from the backend or an error.

func ClientWrite 

func ClientWrite(rcode int) bool

ClientWrite returns true if the response has been written to the client. Each middleware to adhire to this protocol.

func Error 

func Error(name string, err error) error

Error returns err with 'middleware/name: ' prefixed to it.

func ErrorToTxt 

func ErrorToTxt(err error) dns.RR

ErrorToTxt puts in error's text into an TXT RR.

func MX 

func MX(b ServiceBackend, zone string, state request.Request, opt Options) (records, extra []dns.RR, debug []msg.Service, err error)

MX returns MX records from the Backend. If the Target is not a name but an IP address, a name is created on the fly.

func NS 

func NS(b ServiceBackend, zone string, state request.Request, opt Options) (records, extra []dns.RR, debug []msg.Service, err error)

NS returns NS records from the backend

func NextOrFailure 

func NextOrFailure(name string, next Handler, ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

NextOrFailure calls next.ServeDNS when next is not nill, otherwise it will return, a ServerFailure and a nil error.

func PTR 

func PTR(b ServiceBackend, zone string, state request.Request, opt Options) (records []dns.RR, debug []msg.Service, err error)

PTR returns the PTR records from the backend, only services that have a domain name as host are included.

func SOA 

func SOA(b ServiceBackend, zone string, state request.Request, opt Options) ([]dns.RR, []msg.Service, error)

SOA returns a SOA record from the backend.

func SRV 

func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (records, extra []dns.RR, debug []msg.Service, err error)

SRV returns SRV records from the Backend. If the Target is not a name but an IP address, a name is created on the fly.

func ServicesToTxt 

func ServicesToTxt(debug []msg.Service) []dns.RR

ServicesToTxt puts debug in TXT RRs.

func SplitHostPort 

func SplitHostPort(s string) (host, port string, err error)

SplitHostPort splits s up in a host and port portion, taking reverse address notation into account. String the string s should *not* be prefixed with any protocols, i.e. dns://

func TXT 

func TXT(b ServiceBackend, zone string, state request.Request, opt Options) (records []dns.RR, debug []msg.Service, err error)

TXT returns TXT records from Backend or an error.

Types

type Handler 

type Handler interface {
	ServeDNS(context.Context, dns.ResponseWriter, *dns.Msg) (int, error)
	Name() string
}

Handler is like dns.Handler except ServeDNS may return an rcode and/or error.

If ServeDNS writes to the response body, it should return a status code. If the status code is not one of the following:

* SERVFAIL (dns.RcodeServerFailure)

* REFUSED (dns.RecodeRefused)

* FORMERR (dns.RcodeFormatError)

* NOTIMP (dns.RcodeNotImplemented)

CoreDNS assumes *no* reply has yet been written. All other response codes signal other handlers above it that the response message is already written, and that they should not write to it also.

If ServeDNS encounters an error, it should return the error value so it can be logged by designated error-handling middleware.

If writing a response after calling another ServeDNS method, the returned rcode SHOULD be used when writing the response.

If handling errors after calling another ServeDNS method, the returned error value SHOULD be logged or handled accordingly.

Otherwise, return values should be propagated down the middleware chain by returning them unchanged.

type HandlerFunc 

type HandlerFunc func(context.Context, dns.ResponseWriter, *dns.Msg) (int, error)

HandlerFunc is a convenience type like dns.HandlerFunc, except ServeDNS returns an rcode and an error. See Handler documentation for more information.

func (HandlerFunc) Name 

func (f HandlerFunc) Name() string

Name implements the Handler interface.

func (HandlerFunc) ServeDNS 

func (f HandlerFunc) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

ServeDNS implements the Handler interface.

type Host 

type Host string

Host represents a host from the Corefile, may contain port.

func (Host) Normalize 

func (h Host) Normalize() string

Normalize will return the host portion of host, stripping of any port or transport. The host will also be fully qualified and lowercased.

type Middleware 

type Middleware func(Handler) Handler

Middleware is the middle layer which represents the traditional idea of middleware: it chains one Handler to the next by being passed the next Handler in the chain.

type Name 

type Name string

Name represents a domain name.

func (Name) Matches 

func (n Name) Matches(child string) bool

Matches checks to see if other is a subdomain (or the same domain) of n. This method assures that names can be easily and consistently matched.

func (Name) Normalize 

func (n Name) Normalize() string

Normalize lowercases and makes n fully qualified.

type Options 

type Options struct {
	Debug string // This is a debug query. A query prefixed with debug.o-o
}

Options are extra options that can be specified for a lookup.

type ServiceBackend 

type ServiceBackend interface {
	// Services communicates with the backend to retrieve the service definition. Exact indicates
	// on exact much are that we are allowed to recurs.
	Services(state request.Request, exact bool, opt Options) ([]msg.Service, []msg.Service, error)

	// Reverse communicates with the backend to retrieve service definition based on a IP address
	// instead of a name. I.e. a reverse DNS lookup.
	Reverse(state request.Request, exact bool, opt Options) ([]msg.Service, []msg.Service, error)

	// Lookup is used to find records else where.
	Lookup(state request.Request, name string, typ uint16) (*dns.Msg, error)

	// IsNameError return true if err indicated a record not found condition
	IsNameError(err error) bool

	// Debug returns a string used when returning debug services.
	Debug() string

	// Returns _all_ services that matches a certain name.
	// Note: it does not implement a specific service.
	Records(state request.Request, exact bool) ([]msg.Service, error)
}

ServiceBackend defines a (dynamic) backend that returns a slice of service definitions.

type Zones 

type Zones []string

Zones respresents a lists of zone names.

func (Zones) Matches 

func (z Zones) Matches(qname string) string

Matches checks is qname is a subdomain of any of the zones in z. The match will return the most specific zones that matches other. The empty string signals a not found condition.

func (Zones) Normalize 

func (z Zones) Normalize()

Normalize fully qualifies all zones in z. The zones in Z must be domain names, without a port or protocol prefix.

Source Files

View all Source files

Directories

Path Synopsis
Package auto implements an on-the-fly loading file backend.
 Package auto implements an on-the-fly loading file backend.
Package autopath implements autopathing.
 Package autopath implements autopathing.
Package bind allows binding to a specific interface instead of bind to all of them.
 Package bind allows binding to a specific interface instead of bind to all of them.
Package cache implements a cache.
 Package cache implements a cache.
freq
Package freq keeps track of last X seen events.
 Package freq keeps track of last X seen events.
Package chaos implements a middleware that answer to 'CH version.bind TXT' type queries.
 Package chaos implements a middleware that answer to 'CH version.bind TXT' type queries.
Package dnssec implements a middleware that signs responses on-the-fly using NSEC black lies.
 Package dnssec implements a middleware that signs responses on-the-fly using NSEC black lies.
msg
Package msg helps to build a dnstap Message.
 Package msg helps to build a dnstap Message.
out
taprw
Package taprw takes a query and intercepts the response.
 Package taprw takes a query and intercepts the response.
test
Package erratic implements a middleware that returns erratic answers (delayed, dropped).
 Package erratic implements a middleware that returns erratic answers (delayed, dropped).
Package errors implements an HTTP error handling middleware.
 Package errors implements an HTTP error handling middleware.
Package etcd provides the etcd backend middleware.
 Package etcd provides the etcd backend middleware.
msg
Package msg defines the Service structure which is used for service discovery.
 Package msg defines the Service structure which is used for service discovery.
Package federation implements kubernetes federation.
 Package federation implements kubernetes federation.
Package file implements a file backend.
 Package file implements a file backend.
tree
Package tree implements Left-Leaning Red Black trees as described by Robert Sedgewick.
 Package tree implements Left-Leaning Red Black trees as described by Robert Sedgewick.
Package health implements an HTTP handler that responds to health checks.
 Package health implements an HTTP handler that responds to health checks.
Package kubernetes provides the kubernetes backend.
 Package kubernetes provides the kubernetes backend.
Package loadbalance is middleware for rewriting responses to do "load balancing" Package loadbalance shuffles A and AAAA records.
 Package loadbalance is middleware for rewriting responses to do "load balancing" Package loadbalance shuffles A and AAAA records.
Package log implements basic but useful request (access) logging middleware.
 Package log implements basic but useful request (access) logging middleware.
Package metrics implement a handler and middleware that provides Prometheus metrics.
 Package metrics implement a handler and middleware that provides Prometheus metrics.
test
Package test will scrape a target and you can inspect the variables.
 Package test will scrape a target and you can inspect the variables.
vars
pkg
cache
Package cache implements a cache.
 Package cache implements a cache.
debug
dnsrecorder
Package dnsrecorder allows you to record a DNS response when it is send to the client.
 Package dnsrecorder allows you to record a DNS response when it is send to the client.
dnsutil
Package dnsutil contains DNS related helper functions.
 Package dnsutil contains DNS related helper functions.
edns
Package edns provides function useful for adding/inspecting OPT records to/in messages.
 Package edns provides function useful for adding/inspecting OPT records to/in messages.
healthcheck
nonwriter
Package nonwriter implements a dns.ResponseWriter that never writes, but captures the dns.Msg being written.
 Package nonwriter implements a dns.ResponseWriter that never writes, but captures the dns.Msg being written.
rcode
replacer
response
singleflight
Package singleflight provides a duplicate function call suppression mechanism.
 Package singleflight provides a duplicate function call suppression mechanism.
tls
trace
Package pprof implement a debug endpoint for getting profiles using the go pprof tooling.
 Package pprof implement a debug endpoint for getting profiles using the go pprof tooling.
Package proxy is middleware that proxies requests.
 Package proxy is middleware that proxies requests.
Package rewrite is middleware for rewriting requests internally to something different.
 Package rewrite is middleware for rewriting requests internally to something different.
Package secondary implements a secondary middleware.
 Package secondary implements a secondary middleware.
Package test contains helper functions for writing middleware tests.
 Package test contains helper functions for writing middleware tests.
Package trace implements OpenTracing-based tracing
 Package trace implements OpenTracing-based tracing
Package whoami implements a middleware that returns details about the resolving querying it.
 Package whoami implements a middleware that returns details about the resolving querying it.

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