The same cache store should't be added multiple times to the cache stores list (#8)

* request_caching only reads from memory
* added remoteCacheStatus class for retrieving a healthy Redis backend
* updated the test with docker to figure out a possible IP for the Redis docker container
* updated Makefile to only clean the Redis docker instances when running tests
* Updated `make install` with the new folder `status`
* The same cache store should't be added multiple times to the cache stores list
* Updated log message after suggestions from review

Author: selfxp

src/lua/api-gateway/cache/cache.lua

@@ -31,6 +31,28 @@ function _M:new(o)
     return o
 end
 
+---
+-- See if the the cache already exists inside the cache store
+-- @param store
+--
+function _M:hasStore(store)
+    if (store == nil) then
+        ngx.log(ngx.DEBUG, "Store to be compared is nil")
+        return false
+    end
+    for _, cache_store in ipairs(self.__cache_stores) do
+        if (cache_store == nil) then
+            ngx.log(ngx.DEBUG, "Store from cache store is nil" )
+            return false
+        end
+        ngx.log(ngx.DEBUG, "Comparing store named: ", store:getName(), " with existing store named: ", cache_store:getName())
+        if (cache_store:getName() == store:getName()) then
+            return true
+        end
+    end
+    return false
+end
+
 --- Adds a cache into the cache. The order in which the caches are added
 -- is important when reading / writing from/to cache.
 -- @param store An instance of api-gateway.cache.store object.
@@ -41,6 +63,11 @@ function _M:addStore(store)
         return nil
     end
 
+    if (self:hasStore(store)) then
+       ngx.log(ngx.WARN, "Attempt to add a cache store that already exists: ", store:getName())
+       return nil
+    end
+
     local count = #self.__cache_stores
     self.__cache_stores[count + 1] = store
     return self.__cache_stores

test/perl/api-gateway/cache/cache.t

@@ -66,14 +66,19 @@ __DATA__
             assert(stores[1]:getName() == "local_cache", "1st store should be names local_store but it is " .. tostring(stores[1]:getName()))
             assert(stores[2]:getName() == "redis_hash_cache", "2nd store should be names redis_hash_cache but it is " .. tostring(stores[2]:getName()))
 
+            assert(cache:hasStore(local_cache), "local_cache store should already be defined in the cache stores")
+
+            cache:addStore(local_cache)
+            assert(table.getn(stores) == 2, "getStores() should return 2 stores")
+
             ngx.say("OK")
         ';
     }
 
 --- timeout: 5s
 --- request
 GET /t
---- response_body_like eval
+--- response_body_like
 ["OK"]
 --- error_code: 200
 --- no_error_log