Fix host resolution on Darwin, use dig wherever possible #1986
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The `host` and `dig` commands do not return non-zero if a query returns NXDOMAIN or NOERROR, but the DarwinHostProvider was expecting it when deciding whether to fall back to IPv4 if a IPv6 query failed. Therefore, the `host` resource would not function properly when resolving hostnames on Darwin. The logic has been changed to use `dig` short output and query for both v6 and v4 addresses. Additionally, the LinuxHostProvider has been modified to prefer `dig` if it's available to keep behavior similar between Darwin and Linux whenever possible. This has the added benefit of providing v6 and v4 resolution if possible where `getent hosts` only returns v6 if v6 records exist. Signed-off-by: Adam Leff <adam@leff.co>
chris-rock
reviewed
Jul 5, 2017
lib/resources/host.rb
Outdated
| @@ -138,6 +140,26 @@ def missing_requirements(_protocol) | |||
| # be enumerated in a skip_resource message | |||
| [] | |||
| end | |||
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| def resolve_with_dig(hostname) | |||
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It feels like we need a new UnixHostProvider class to map those functions.
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Yeah I can totally do that. You thinking DarwinHostProvider and LinuxHostProvider would subclass from it, and we'd move both resolve_with_bind and resolve_with_getent into it?
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exactly, that was my thinking.
Signed-off-by: Adam Leff <adam@leff.co>
Signed-off-by: Adam Leff <adam@leff.co>
chris-rock
approved these changes
Jul 5, 2017
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The
hostanddigcommands do not return non-zero if a query returns NXDOMAIN or NOERROR, but the DarwinHostProvider was expecting it when deciding whether to fall back to IPv4 if a IPv6 query failed. Therefore, thehostresource would not function properly when resolving hostnames on Darwin. The logic has been changed to usedigshort output and query for both v6 and v4 addresses.Additionally, the LinuxHostProvider has been modified to prefer
digif it's available to keep behavior similar between Darwin and Linux whenever possible. This has the added benefit of providing v6 and v4 resolution if possible wheregetent hostsonly returns v6 if v6 records exist.