Merge pull request #511 from 3scale/resolver-ipv6

[resty.resolver] support ipv6 resolvers

CHANGELOG.md

@@ -26,6 +26,7 @@ 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]
 

bin/busted

@@ -14,6 +14,7 @@ chdir "$dirname/..";
 my $apicast = getcwd();
 
 exec '/usr/bin/env', 'resty',
+    '--errlog-level', 'alert',
     '--http-include', "$apicast/spec/fixtures/echo.conf",
     "$apicast/bin/busted.lua",
     '--config-file', "$apicast/.busted",

gateway/src/resty/resolver.lua

@@ -8,12 +8,15 @@ local find = string.find
 local rep = string.rep
 local unpack = unpack
 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'
+local resty_env = require 'resty.env'
 local upstream = require 'ngx.upstream'
 local re = require('ngx.re')
 local semaphore = require "ngx.semaphore"
@@ -53,6 +56,14 @@ local function read_resolv_conf(path)
   return output or "", err
 end
 
+local function ipv4(address)
+  return re_match(address, '^([0-9]{1,3}\\.){3}[0-9]{1,3}$', 'oj')
+end
+
+local function ipv6(address)
+  return re_match(address, '^\\[[a-f\\d:]+\\]$', 'oj')
+end
+
 local nameserver = {
   mt = {
     __tostring = function(t)
@@ -62,9 +73,35 @@ local nameserver = {
 }
 
 function nameserver.new(host, port)
+  if not ipv4(host) and not ipv6(host) then
+    -- then it is likely ipv6 without [ ] around
+    host = format('[%s]', host)
+  end
   return setmetatable({ host, port or default_resolver_port }, nameserver.mt)
 end
 
+function _M.parse_resolver(resolver)
+  if not resolver then return end
+
+  local m, err = re_match(resolver, [[^
+      (
+        (?:\d{1,3}\.){3}\d{1,3} # ipv4
+        |
+        \[[a-f\d:]+\] # ipv6 in [ ] brackes, like [dead::beef]
+        |
+        [a-f\d:]+ # ipv6 without brackets
+      )
+      (?:\:(\d+))? # optional port
+    $]], 'ojx')
+
+  if m then
+    return nameserver.new(m[1], m[2])
+  else
+    return resolver, err or 'invalid address'
+  end
+end
+
+
 function _M.parse_nameservers(path)
   local resolv_conf, err = read_resolv_conf(path)
 
@@ -76,7 +113,6 @@ function _M.parse_nameservers(path)
 
   local search = { }
   local nameservers = { search = search }
-  local resolver = getenv('RESOLVER')
   local domains = match(resolv_conf, 'search%s+([^\n]+)')
 
   ngx.log(ngx.DEBUG, 'search ', domains)
@@ -85,11 +121,15 @@ function _M.parse_nameservers(path)
     insert(search, domain)
   end
 
-  if resolver then
-    local m = re.split(resolver, ':', 'oj')
-    insert(nameservers, nameserver.new(m[1], m[2]))
+  local resolver
+  resolver, err = _M.parse_resolver(resty_env.value('RESOLVER'))
+
+  if err then
+    ngx.log(ngx.ERR, 'invalid resolver ', resolver, ' error: ', err)
+  elseif resolver 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, resolver)
   end
 
   for server in gmatch(resolv_conf, 'nameserver%s+([^%s]+)') do

spec/resty/resolver_spec.lua

@@ -129,8 +129,36 @@ describe('resty.resolver', function()
     pending('does query when cached cname missing address')
   end)
 
+  describe('.parse_resolver', function()
+
+    it("handles invalid data", function()
+      assert.same({'foobar', 'invalid address'}, { resty_resolver.parse_resolver('foobar') })
+    end)
+
+    it("handles missing data", function()
+      assert.same({}, { resty_resolver.parse_resolver() })
+    end)
+
+    it("parses ipv4 without port", function()
+      assert.same({'192.168.0.1', 53}, resty_resolver.parse_resolver('192.168.0.1'))
+    end)
+
+    it("parses ipv4 with port", function()
+      assert.same({'192.168.0.1', '5353'}, resty_resolver.parse_resolver('192.168.0.1:5353'))
+    end)
+
+    it("parses ipv6 without port", function()
+      assert.same({'[dead::beef:5353]', 53}, resty_resolver.parse_resolver('dead::beef:5353'))
+    end)
+
+    it("parses ipv6 with port", function()
+      assert.same({'[dead::beef]', '5353'}, resty_resolver.parse_resolver('[dead::beef]:5353'))
+    end)
+  end)
+
   describe('.parse_nameservers', function()
     local tmpname
+    local resty_env = require('resty.env')
 
     before_each(function()
       tmpname = io.tmpfile()
@@ -155,6 +183,22 @@ describe('resty.resolver', function()
       assert.same({ 'localdomain.example.com', 'local' },  search)
     end)
 
+    it('ignores invalid RESOLVER', function()
+      resty_env.set('RESOLVER', 'invalid-nameserver')
+
+      local nameservers = resty_resolver.parse_nameservers('')
+
+      assert.equal(0, #nameservers)
+    end)
+
+    it('uses correct RESOLVER', function()
+      resty_env.set('RESOLVER', '192.168.0.1:53')
+
+      local nameservers = resty_resolver.parse_nameservers('')
+
+      assert.equal(1, #nameservers)
+      assert.same({'192.168.0.1', '53'}, nameservers[1])
+    end)
   end)
 
 end)

t/resolver.t

@@ -2,13 +2,10 @@ use lib 't';
 use TestAPIcast 'no_plan';
 
 $ENV{TEST_NGINX_HTTP_CONFIG} = "$TestAPIcast::path/http.d/*.conf";
-$ENV{RESOLVER} = '127.0.1.1:5353';
+$ENV{TEST_NGINX_RESOLVER} = '127.0.1.1:5353';
 
 $ENV{TEST_NGINX_RESOLV_CONF} = "$Test::Nginx::Util::HtmlDir/resolv.conf";
 
-env_to_nginx(
-    'RESOLVER'
-);
 master_on();
 log_level('warn');
 run_tests();
@@ -17,9 +14,11 @@ __DATA__
 
 === TEST 1: uses all resolvers
 both RESOLVER env variable and resolvers in resolv.conf should be used
+--- main_config
+env RESOLVER=$TEST_NGINX_RESOLVER;
 --- http_config
   lua_package_path "$TEST_NGINX_LUA_PATH";
-  init_by_lua_block {
+  init_worker_by_lua_block {
     require('resty.resolver').init('$TEST_NGINX_RESOLV_CONF')
   }
 --- config
@@ -67,3 +66,27 @@ servers: 2
 2.3.4.5:6789
 --- no_error_log
 [error]
+
+
+=== TEST 3: can have ipv6 RESOLVER
+RESOLVER env variable can be IPv6 address
+--- main_config
+env RESOLVER=[dead::beef]:5353;
+--- http_config
+  lua_package_path "$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