Add multi-domain support via alias zones using ZoneOrigins class

[Copilot]

Multi-Domain DNS Support - ZoneOrigins Integration

• Integrate ZoneOrigins class into DNS configuration
• Update DnsServerConfig to use zone_origins instead of origin_name + alias_zones
• Update config factory to create ZoneOrigins instance
• Update UDP handler to use ZoneOrigins.relativize() method
• Update zone updater to use zone_origins.primary
• Update main.py to pass zone_origins to server
• Update all tests (184 passing)
• Remove redundant multi-domain test files
• Clean up unused code and redundant validation
• Simplify _make_zone_origins function
• Add Python object protocol methods to ZoneOrigins class

Changes Made

Core Integration:

• DNS server now supports multiple domains (e.g., long.com and short.com) with the same subdomains resolving to the same IPs
• Single zone maintained internally with health checks performed only once
• Query normalization handled transparently via ZoneOrigins.relativize() method

ZoneOrigins Class Enhancement:

• Added __eq__ method for proper equality comparison based on primary zone and origins
• Added __hash__ method to enable use in sets and as dictionary keys
• Added __repr__ method for readable string representation showing primary and aliases
• 9 new tests added to validate equality, hashing, and repr functionality

Code Simplification:

• Removed unnecessary conditional logging in _make_zone_origins()
• Removed redundant subdomain conflict validation (handled by ZoneOrigins)
• Removed unused _make_alias_zones() function
• Cleaned up test fixtures to use zone_origins.primary consistently

Interface

Command-line:

a-healthy-dns \
  --hosted-zone primary.com \
  --alias-zones '["alias1.com", "alias2.com"]' \
  --zone-resolutions '{"www": {"ips": ["192.168.1.100"], "health_port": 8080}}' \
  --ns '["ns1.primary.com"]'

Docker:

• Supports DNS_ALIAS_ZONES environment variable

Result

• All 184 tests passing
• www.primary.com, www.alias1.com, and www.alias2.com all resolve to the same IP with a single health check
• ZoneOrigins class fully integrated with complete Python object protocol support
• Clean, maintainable codebase with no redundant validation logic

Original prompt

This project code a DNS server based on dnspython library.

In a nutshell, a dnspython zone is filled at the beginning with the data provided with input parameters when the server is launched and, later, A records in the zone are regularly checked to ensure the are still valid.

Then DNS queries are replied based on the updated info into the aforementioned dnspython zone.

However, this zone is linked to a single domain/origin. I would like this DNS server to be able to reply to queries for multiple domains/origin. But I do not want this server to maintain multiples zones, I want have only one. To be clearer, let's imagine the following scenario:

• I have domain long.com
• And I also have short.com
• I want this DNS server to resolve vm1.long.com and vm1.short.com to the same A record

I understand the simplest thing would be to have one dnspython zone per domain/origin with the same A records in all of them. But a key functionality of this server is to check the health of servers behind the A records. If the zone is duplicated, then the checked servers will receive double the numbers of health requests. And the workload on the DNS server itself double too.

I could consider to create a DNS zone per domain as long as that would not imply to double the workload as described before.

So, in a nutshell, I want this DNS server to be able to reply to DNS queries for 2 or more domains/origins (with the same subdomains) without increasing the workload to validate the informed A records are still healthy

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[indisoluble]

@copilot I have pushed some changes over your first proposal, including a new class named ZoneOrigins. Analyze the aforementioned class carefully, I want you to integrate it (as is) in the project meaning:

• DNS configuration factory must produce the config including, instead of a hosted zone + aliases, a single instance of ZoneOrigins
• Then, UDP handler must use the relativize method in this new class to get a node and continue workflow as before

Once changes are applied, review tests and fox them accordingly, including adding new tests or removing those that are redundant, if necessary

[Copilot]

@copilot I have pushed some changes over your first proposal, including a new class named ZoneOrigins. Analyze the aforementioned class carefully, I want you to integrate it (as is) in the project m...

Done in commit d8f52d0. The ZoneOrigins class has been fully integrated:

• DnsServerConfig now uses zone_origins: ZoneOrigins instead of separate origin_name and alias_zones fields
• Config factory creates ZoneOrigins via _make_zone_origins() which validates the primary zone and alias list
• UDP handler uses zone_origins.relativize() to normalize query names from any configured zone
• Zone updater accesses the primary origin via config.zone_origins.primary
• Main.py passes zone_origins to the server

All 175 tests passing. The redundant multi-domain test files were removed since the functionality is now properly tested in test_zone_origins.py.

[indisoluble]

@copilot Address latest comments

[Copilot]

@copilot Address latest comments

All comments addressed in commit 1216b0f:

• Removed unused _make_alias_zones() function
• Removed docstring comment from _make_zone_origins()
• Removed subdomain conflict validation code (handled by ZoneOrigins)

All 175 tests passing.

[Copilot]

@copilot Address latest 2 comments in code

Both comments addressed in commit 7883209:

• Removed the if alias_zones: check and logging message
• Moved return statement to the end of the function

All 175 tests passing.

[indisoluble]

@copilot Address new set of comments

[Copilot]

@copilot Address new set of comments

All comments addressed in commit 6a42800:

• Added __eq__, __hash__, and __repr__ methods to ZoneOrigins with 9 new tests
• Reordered and refactored fixtures in test_dns_server_udp_handler.py
• Removed unused origin_name fixture from test_dns_server_zone_updater.py
• Removed unused mock_origin_name fixture from test_dns_server_zone_updater_threated.py

All 184 tests passing.