Policy: Content Caching disable totally

When using content_cache and proxy_no_cache, some directives are still
in place, and was causing issues to a few users regarding HEAD request,
etc..

This commit disabled the proxy_cache globally based on cache_zone
variable.

FIX THREESCALE-7016

Signed-off-by: Eloy Coto <eloy.coto@acalustra.com>

gateway/conf.d/apicast.conf

@@ -77,7 +77,7 @@ location @upstream {
   }
 
   #{% capture proxy_cache_valid %}
-  #{#} proxy_cache apicast_cache;
+  #{#} proxy_cache $cache_zone;
   #{#} proxy_cache_key $scheme$request_method$proxy_host$request_uri$service_id;
   #{#} proxy_no_cache $cache_request;
   #{#} proxy_cache_valid {{ env.APICAST_CACHE_STATUS_CODES | default: '200 302'}} {{ env.APICAST_CACHE_MAX_TIME | default: '1m' }};
@@ -166,6 +166,7 @@ location / {
 
   # Variable to enable/disable content cache
   set $cache_request 'true';
+  set $cache_zone 'off';
 
   set $original_request_id $request_id;
 

gateway/src/apicast/policy/content_caching/content_caching.lua

@@ -11,6 +11,8 @@ local metrics_updater = require('apicast.metrics.updater')
 
 local content_cache_metric = prometheus('counter', "content_caching", "Content caching status", {"status"})
 
+local cache_zone = "apicast_cache"
+
 local new = _M.new
 
 function _M.new(config)
@@ -30,7 +32,9 @@ function _M.new(config)
 end
 
 function _M:access(context)
+  ngx.var.cache_zone = cache_zone
   ngx.var.cache_request = "true"
+
   for _, rule in ipairs(self.rules or {}) do
     local cond_is_true = rule.condition:evaluate(context)
     if cond_is_true and rule.cache then

t/apicast-policy-content-caching.t

@@ -429,3 +429,103 @@ __DATA__
 ["X-Cache-Status: MISS", "X-Cache-Status: MISS"]
 --- no_error_log
 [error]
+
+
+
+=== TEST 8: HEAD request is enabled if no content-caching
+--- configuration
+{
+  "services": [
+    {
+      "id": 42,
+      "proxy": {
+        "hosts": ["one"],
+        "policy_chain": [
+          {
+            "name": "apicast.policy.upstream",
+            "configuration":
+              {
+                "rules": [ { "regex": "/", "url": "http://test:$TEST_NGINX_SERVER_PORT/" } ]
+              }
+          }
+        ]
+      }
+    }
+  ]
+}
+--- upstream
+  location / {
+     content_by_lua_block {
+       local assert = require('luassert')
+       assert.same(ngx.var.request_method, "HEAD")
+     }
+  }
+--- request
+HEAD /foo
+--- more_headers
+Host: one
+--- expected_response_body_like_multiple eval
+yay, api backend
+--- error_code: 200
+--- no_error_log
+[error]
+
+=== TEST 9: HEAD request is disabled when using content-caching
+--- configuration
+{
+  "services": [
+    {
+      "id": 42,
+      "proxy": {
+        "hosts": ["one"],
+        "policy_chain": [
+          {
+            "name": "apicast.policy.content_caching",
+            "version": "builtin",
+            "configuration": {
+              "rules": [
+                {
+                  "cache": true,
+                  "header": "X-Cache-Status",
+                  "condition": {
+                    "combine_op": "and",
+                    "operations": [
+                      {
+                        "left": "oo",
+                        "op": "==",
+                        "right": "oo"
+                      }
+                    ]
+                  }
+                }
+              ]
+            }
+          },
+          {
+            "name": "apicast.policy.upstream",
+            "configuration":
+              {
+                "rules": [ { "regex": "/", "url": "http://test:$TEST_NGINX_SERVER_PORT/" } ]
+              }
+          }
+        ]
+      }
+    }
+  ]
+}
+--- upstream
+  location / {
+     content_by_lua_block {
+       local assert = require('luassert')
+       assert.same(ngx.var.request_method, "GET")
+     }
+  }
+--- request
+HEAD /foo
+--- more_headers
+Host: one
+--- expected_response_body_like_multiple eval
+yay, api backend
+--- error_code: 200
+--- no_error_log
+[error]