[processor/dnslookup] Add DNS resolver with hostfile, nameserver, and caching support #40390
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…r, and caching support This PR introduces the core DNS resolution functionality for use in the `dnslookupprocessor`. - Resolver interface: Defines forward and reverse DNS lookup operations. - Hostfile resolver: Supports resolving from one or more hostfiles. - Nameserver resolver: Supports custom DNS servers and system resolver. It retries with exponential backoff on failures. - Chain resolver: Attempts resolution through a sequence of resolvers. Returns the first successful result. No resolution is considered a success - Cache resolver - Cache results from chain resolvers. Successful resolutions are stored in the hit cache. Failed lookups are stored in miss cache. Implements LRU caching with TTL support.
kaisecheng
requested review from
andrzej-stencel,
edmocosta and
a team
as code owners
|
@edmocosta I believe this is ready for review. |
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Description
This PR introduces the core DNS resolution functionality for use in the
dnslookupprocessor.Note that later hostfiles in the list take precedence over earlier ones for duplicate entries.
When hostname is not in files, the processor continues to the next resolver in the chain.
It performs A/CNAME record lookups to resolve hostnames to IP addresses,
and PTR record lookups for reverse DNS resolution (IP to hostname)
It retries with exponential backoff on failures.
The resolver prefers IPv4 addresses over IPv6 when both are available.
Returns the first successful result. No resolution is considered a success.
Designed to support a resolution chain such as: hostfile -> nameserver -> system default.
The actual resolver chain initialization logic will be added in the next PR.
Successful resolutions are stored in the hit cache.
Failed lookups are stored in miss cache.
Implements LRU caching with TTL support.
The current processor is a no-op, as user configuration and signal processing are not yet implemented
Link to tracking issue
#34398
Testing
Added unit tests for all resolvers
Documentation