Safe Haskell	Safe-Inferred
Language	Haskell2010

Ouroboros.Network.PeerSelection.RootPeersDNS.DNSActions

Contents

Synopsis

DNS based actions for local and public root providers

data DNSActions resolver exception m Source #

Dictionary of DNS actions vocabulary

Constructors

Fields

dnsResolverResource ∷ ResolvConf → m (Resource m (Either (DNSorIOError exception) resolver))
TODO: it could be useful for publicRootPeersProvider.
dnsAsyncResolverResource ∷ ResolvConf → m (Resource m (Either (DNSorIOError exception) resolver))
Resource which passes the Resolver (or abstract resolver type) through a StrictTVar. Better than resolverResource when using in multiple threads.
On Windows we use a different implementation which always returns a newly initialised Resolver at each step. This is because on Windows we don't have a way to check that the network configuration has changed. The dns library is using 'GetNetworkParams@ win32 api call to get the list of default dns servers.
dnsLookupWithTTL ∷ ResolvConf → resolver → Domain → m ([DNSError], [(IP, TTL)])
Like lookupA but also return the TTL for the results.
DNS library timeouts do not work reliably on Windows (#1873), hence the additional timeout.

DNSActions IO

IO DNSActions which resolve domain names with Resolver.

The IPv4 and IPv6 addresses the node will be using should determine the LookupReqs so that we can avoid lookups for address types that wont be used.

It guarantees that returned TTLs are strictly greater than 0.

Constructors

Instances details

Show DNSLookupType Source #
Instance details Defined in Ouroboros.Network.PeerSelection.RootPeersDNS.DNSActions Methods showsPrec ∷ Int → DNSLookupType → ShowS # show ∷ DNSLookupType → String # showList ∷ [DNSLookupType] → ShowS #

Evolving resource; We use it to reinitialise the DNS library if the `etcresolv.conf` file was modified.

Note: constantResource and retryResource are written using a simplified approach inspired by _"The Different Aspects of Monads and Mixins"_, by Bruno C. d S. Oliveira, see https://www.youtube.com/watch?v=pfwP4hXM5hA.

Constructors

Resource
Fields withResource ∷ m (a, Resource m a)

Instances details

Functor m ⇒ Functor (Resource m) Source #
Instance details Defined in Ouroboros.Network.PeerSelection.RootPeersDNS.DNSActions Methods fmap ∷ (a → b) → Resource m a → Resource m b # (<$) ∷ a → Resource m b → Resource m a #

A Resource which will exhibit the given Resource but retry it with a given delay until a success. On first success it will reset the delays.

Constructors

DNSError !DNSError
IOError !exception

Instances details

Exception exception ⇒ Exception (DNSorIOError exception) Source #
Instance details Defined in Ouroboros.Network.PeerSelection.RootPeersDNS.DNSActions Methods toException ∷ DNSorIOError exception → SomeException # fromException ∷ SomeException → Maybe (DNSorIOError exception) # displayException ∷ DNSorIOError exception → String #
Show exception ⇒ Show (DNSorIOError exception) Source #
Instance details Defined in Ouroboros.Network.PeerSelection.RootPeersDNS.DNSActions Methods showsPrec ∷ Int → DNSorIOError exception → ShowS # show ∷ DNSorIOError exception → String # showList ∷ [DNSorIOError exception] → ShowS #