[resty.resolver] properly parse ipv6 RESOLVER env

CHANGELOG.md

@@ -24,6 +24,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## Fixed
 
 - Loading installed luarocks from outside rover [PR #503](https://github.com/3scale/apicast/pull/503)
+- Support IPv6 addresses in `/etc/resolv.conf` [PR #511](https://github.com/3scale/apicast/pull/511)
 
 ## [3.2.0-alpha1]
 

gateway/src/resty/resolver.lua

@@ -11,6 +11,9 @@ local insert = table.insert
 local getenv = os.getenv
 local concat = table.concat
 local io_type = io.type
+
+require('resty.core.regex') -- to allow use of ngx.re.match in the init phase
+
 local re_match = ngx.re.match
 local resolver_cache = require 'resty.resolver.cache'
 local dns_client = require 'resty.resolver.dns_client'
@@ -98,10 +101,17 @@ function _M.parse_nameservers(path)
   end
 
   if resolver then
-    local m = re.split(resolver, ':', 'oj')
-    insert(nameservers, nameserver.new(m[1], m[2]))
-    -- we are going to use all resolvers, because we can't trust dnsmasq
-    -- see https://github.com/3scale/apicast/issues/321 for more details
+    local m
+
+    m, err = re_match(resolver, '^(.+?)(?<!:)(?:\\:(\\d+))?$', 'oj')
+
+    if m then
+      -- we are going to use all resolvers, because we can't trust dnsmasq
+      -- see https://github.com/3scale/apicast/issues/321 for more details
+      insert(nameservers, nameserver.new(m[1], m[2]))
+    else
+      ngx.log(ngx.ERR, 'invalid resolver ', resolver, ' error: ', err)
+    end
   end
 
   for server in gmatch(resolv_conf, 'nameserver%s+([^%s]+)') do

t/resolver.t

@@ -66,3 +66,28 @@ servers: 2
 2.3.4.5:6789
 --- no_error_log
 [error]
+
+
+=== TEST 3: can have ipv6 RESOLVER
+RESOLVER env variable can be IPv6 address
+--- ONLY
+--- main_config
+env RESOLVER=[dead::beef]:5353;
+--- http_config
+  lua_package_path "$TEST_NGINX_LUA_PATH";
+  init_worker_by_lua_block {
+    require('resty.resolver').init('$TEST_NGINX_RESOLV_CONF')
+  }
+--- config
+  location = /t {
+    content_by_lua_block {
+      local nameservers = require('resty.resolver').nameservers()
+      ngx.say('nameservers: ', #nameservers, ' ', tostring(nameservers[1]))
+    }
+  }
+--- request
+GET /t
+--- response_body
+nameservers: 1 [dead::beef]:5353
+--- user_files
+>>> resolv.conf