[policy] trigger post_action phase

sharing context to post_action enables executing the phase
with all context from the main request - including policy chain

gateway/conf.d/apicast.conf

@@ -48,7 +48,10 @@ location @out_of_band_authrep_action {
 
   set_by_lua $original_request_time 'return ngx.var.request_time';
 
-  content_by_lua_block { require('apicast.executor'):post_action() }
+  content_by_lua_block {
+    require('resty.ctx').apply()
+    require('apicast.executor'):post_action()
+ }
 
   log_by_lua_block {
     ngx.var.post_action_impact = ngx.var.request_time - ngx.var.original_request_time
@@ -70,12 +73,17 @@ location / {
   set $version '';
   set $real_url null;
 
+  set $ctx_ref -1;
+
   set $post_action_impact null;
   set $original_request_id null;
 
   proxy_ignore_client_abort on;
 
-  rewrite_by_lua_block { require('apicast.executor'):rewrite() }
+  rewrite_by_lua_block {
+    require('resty.ctx').stash()
+    require('apicast.executor'):rewrite()
+  }
   access_by_lua_block { require('apicast.executor'):access() }
   body_filter_by_lua_block { require('apicast.executor'):body_filter() }
   header_filter_by_lua_block { require('apicast.executor'):header_filter() }

t/apicast-policy-chains.t

@@ -65,3 +65,4 @@ running phase: access
 running phase: balancer
 running phase: header_filter
 running phase: body_filter
+running phase: post_action

t/apicast.t

@@ -108,7 +108,7 @@ Content-Type: text/plain; charset=utf-8
 no mapping rules!
 --- error_code: 404
 --- error_log
-could not find proxy for request
+skipping after action, no cached key
 
 === TEST 5: no mapping rules matched configurable error
 The message is configurable and status also.
@@ -136,7 +136,7 @@ GET /?user_key=value
 no mapping rules!
 --- error_code: 412
 --- error_log
-could not find proxy for request
+skipping after action, no cached key
 
 === TEST 6: authentication credentials invalid default error
 There are defaults defined for the error message, the content-type, and the