mxresolv

Documentation

Index

• Variables
• func Lookup(ctx context.Context, domainName string) (mxHosts []string, implicit bool, err error)
• func LookupWithPref(ctx context.Context, domainName string) (mxRecords []*net.MX, implicit bool, err error)
• func ResetCache()
• func SetDeterministicInTests() func()

Variables

var (

	// Resolver is exposed to be patched in tests
	Resolver = net.DefaultResolver
)

Functions

func Lookup

func Lookup(ctx context.Context, domainName string) (mxHosts []string, implicit bool, err error)

Lookup performs a DNS lookup of MX records for the specified domain. It returns a prioritised list of MX hostnames, where hostnames with the same priority are shuffled. If the second returned value is true, then the host does not have explicit MX records, and its A record is returned instead.

It uses an LRU cache with a timeout to reduce the number of network requests.

func LookupWithPref

func LookupWithPref(ctx context.Context, domainName string) (mxRecords []*net.MX, implicit bool, err error)

LookupWithPref performs a DNS lookup of MX records for the specified domain. It returns a slice of net.MX records that are ordered by preference. Records with the same preference are sorted by hostname to ensure deterministic behaviour. If the second returned value is true, then the host does not have explicit MX records, and its A record is used instead.

It uses an LRU cache with a timeout to reduce the number of network requests.

func ResetCache

func ResetCache()

ResetCache clears the cache for use in tests, and is not Thread-Safe

func SetDeterministicInTests

func SetDeterministicInTests() func()

SetDeterministicInTests sets rand to deterministic seed for testing, and is not Thread-Safe.