Avoid nameserver duplication

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Error loading policy chain configuration JSON with null value [PR #626](https://github.com/3scale/apicast/pull/626)
 - Splitted `resolv.conf` in lines,to avoid commented lines  [PR #618](https://github.com/3scale/apicast/pull/618)
+- Avoid `nameserver` repetion from `RESOLVER` variable and `resolv.conf` file [PR #636](https://github.com/3scale/apicast/pull/636)
 
 ## Added
 

gateway/src/resty/resolver.lua

@@ -140,7 +140,8 @@ function _M.parse_nameservers(path)
 
     local server = match(line, '^nameserver%s+([^%s]+)')
     -- TODO: implement port matching based on https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=549190
-    if server and server ~= resolver then
+    --       meanwhile assuming default port 53.
+    if server and format("%s:%s", server, default_resolver_port) ~= tostring(resolver) then
       insert(nameservers, nameserver.new(server))
     end
   end

spec/resty/resolver_spec.lua

@@ -182,10 +182,19 @@ nameserver 127.0.0.1
       local nameservers = resty_resolver.parse_nameservers(tmpname)
 
       assert.equal(2, #nameservers)
-      assert.same({ '127.0.0.2', 53 },  nameservers[1])
+      assert.same({ '127.0.0.2', 53 }, nameservers[1])
       assert.same({ '127.0.0.1', 53 }, nameservers[2])
     end)
 
+    it('do not replicates nameservers from resolver env var', function()
+      resty_env.set('RESOLVER', '127.0.0.1')
+      local nameservers = resty_resolver.parse_nameservers(tmpname)
+
+      assert.equal(2, #nameservers)
+      assert.same({ '127.0.0.1', 53 }, nameservers[1])
+      assert.same({ '127.0.0.2', 53 }, nameservers[2])
+    end)
+
     it('returns search domains', function()
       local search = resty_resolver.parse_nameservers(tmpname).search
 

t/resolver.t

@@ -101,3 +101,29 @@ GET /t
 nameservers: 1 [dead::beef]:5353
 --- user_files
 >>> resolv.conf
+
+
+=== TEST 4: do not duplicate nameserver from RESOLVER
+nameservers should not repeat if already configured
+--- main_config
+env RESOLVER='127.0.1.1:53';
+--- 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, ' ', nameservers[1], ' ', nameservers[2])
+    }
+  }
+--- request
+GET /t
+--- response_body
+nameservers: 2 127.0.1.153 1.2.3.453
+--- user_files
+>>> resolv.conf
+nameserver 127.0.1.1
+nameserver 1.2.3.4