Fix bug in export() applied to policies in the local chain

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Rate Limit policy [PR #648](https://github.com/3scale/apicast/pull/648)
 - [THREESCALE-799](https://issues.jboss.org/browse/THREESCALE-799) Documented restrictions in the position in the chain for some policies [PR #675](https://github.com/3scale/apicast/pull/675)
 
+### Fixed
+
+- `export()` now works correctly in policies of the local chain [PR #673](https://github.com/3scale/apicast/pull/673)
+
 ### Changed
 
 - descriptions in `oneOf`s in policy manifests have been replaced with titles [PR #663](https://github.com/3scale/apicast/pull/663)

gateway/src/apicast/policy/local_chain/local_chain.lua

@@ -2,6 +2,7 @@ local resty_env = require('resty.env')
 
 local policy = require('apicast.policy')
 local Proxy = require('apicast.proxy')
+local LinkedList = require('apicast.linked_list')
 local _M = policy.new('Local Policy Chain')
 
 local function build_default_chain()
@@ -27,7 +28,11 @@ local function build_chain(context)
   local proxy = Proxy.new(context.configuration)
 
   context.proxy = context.proxy or proxy
-  context.policy_chain = find_policy_chain(context)
+
+  local policy_chain = find_policy_chain(context)
+  context.policy_chain = policy_chain
+
+  return policy_chain
 end
 
 -- forward all policy methods to the policy chain
@@ -44,7 +49,10 @@ end
 local rewrite = _M.rewrite
 
 function _M:rewrite(context, ...)
-  build_chain(context)
+  local policy_chain = build_chain(context)
+
+  context = LinkedList.readwrite(context, policy_chain:export())
+
   rewrite(self, context, ...)
 end
 

spec/policy/local_chain/local_chain_spec.lua

@@ -0,0 +1,83 @@
+local LocalChain = require 'apicast.policy.local_chain'
+local policy = require 'apicast.policy'
+local PolicyChain = require 'apicast.policy_chain'
+
+describe('local chain', function()
+  describe('.rewrite', function()
+    -- In all these tests, we export some data in 2 policies of the local
+    -- chain, then call rewrite() on the local chain, and finally, check that
+    -- each policy has the correct context when it runs its rewrite() method.
+
+    it('forwards a context that includes the data exported by the policies', function()
+      local assert_correct_context = function(_, context)
+        assert.equals(context.shared_data_1, 'from_policy_1')
+        assert.equals(context.shared_data_2, 'from_policy_2' )
+      end
+
+      local policy_1 = policy.new()
+      policy_1.export = function() return { shared_data_1 = 'from_policy_1' } end
+      policy_1.rewrite = assert_correct_context
+
+      local policy_2 = policy.new()
+      policy_2.export = function() return { shared_data_2 = 'from_policy_2' } end
+      policy_2.rewrite = assert_correct_context
+
+      local policy_chain = PolicyChain.build({ policy_1, policy_2 })
+
+      -- Passing policy_chain in the context. That way the local_chain will use
+      -- it instead of building a new one.
+      -- Configuration is needed to avoid instantiating a proxy
+      local context = { configuration = {}, policy_chain = policy_chain }
+
+      LocalChain.new():rewrite(context)
+    end)
+
+    describe('when there are several policies exposing the same data', function()
+      it('gives precedence to the first policy in the chain', function()
+        local assert_correct_context = function(_, context)
+          assert.equals(context.shared_data, 'from_policy_1')
+        end
+
+        local policy_1 = policy.new()
+        policy_1.export = function() return { shared_data = 'from_policy_1' } end
+        policy_1.rewrite = assert_correct_context
+
+        local policy_2 = policy.new()
+        policy_2.export = function() return { shared_data = 'from_policy_2' } end
+        policy_2.rewrite = assert_correct_context
+
+        local policy_chain = PolicyChain.build({ policy_1, policy_2 })
+
+        local context = { configuration = {}, policy_chain = policy_chain }
+
+        LocalChain.new():rewrite(context)
+      end)
+    end)
+
+    describe('when the context already includes some data', function()
+      it('gives precedence to that data over the one in the local chain', function()
+        local assert_correct_context = function(_, context)
+          assert.equals(context.shared_data, 'from_context')
+        end
+
+        local policy_1 = policy.new()
+        policy_1.export = function() return { shared_data = 'from_policy_1' } end
+        policy_1.rewrite = assert_correct_context
+
+        local policy_2 = policy.new()
+        policy_2.export = function() return { shared_data = 'from_policy_2' } end
+        policy_2.rewrite = assert_correct_context
+
+        local policy_chain = PolicyChain.build({ policy_1, policy_2 })
+
+        local context = {
+          configuration = {},
+          policy_chain = policy_chain,
+          shared_data = 'from_context'
+        }
+
+        LocalChain.new():rewrite(context)
+      end)
+    end)
+  end)
+end)