fix(proxy-cache) avoid HTTP 500 in /proxy-cache when multiple plugins…

… are active

Avoid a HTTP 500 error triggered in the global `/proxy-cache` endpoint
when other plugins are also active. This fixes the iteration logic
to ensure it goes only through the proxy-cache plugins.

Fixes #12

kong/plugins/proxy-cache/api.lua

@@ -12,16 +12,32 @@ local function broadcast_purge(plugin_id, cache_key)
 end
 
 
+local function each_proxy_cache()
+  local iter = kong.db.plugins:each()
+
+  return function()
+    while true do
+      local plugin, err = iter()
+      if err then
+        return kong.response.exit(500, { message = err })
+      end
+      if not plugin then
+        return
+      end
+      if plugin.name == "proxy-cache" then
+        return plugin
+      end
+    end
+  end
+end
+
+
 return {
   ["/proxy-cache"] = {
     resource = "proxy-cache",
 
     DELETE = function()
-      for plugin, err in kong.db.plugins:each(1000,
-        { cache_key = "proxy-cache", }) do
-        if err then
-          return kong.response.exit(500, { message = err })
-        end
+      for plugin in each_proxy_cache() do
 
         local strategy = require(STRATEGY_PATH)({
           strategy_name = plugin.config.strategy,
@@ -51,11 +67,7 @@ return {
     resource = "proxy-cache",
 
     GET = function(self)
-      for plugin, err in kong.db.plugins:each(1000,
-        { cache_key = "proxy-cache", }) do
-        if err then
-          return kong.response.exit(500, { message = err })
-        end
+      for plugin in each_proxy_cache() do
 
         local strategy = require(STRATEGY_PATH)({
           strategy_name = plugin.config.strategy,
@@ -78,11 +90,7 @@ return {
     end,
 
     DELETE = function(self)
-      for plugin, err in kong.db.plugins:each(1000,
-        { cache_key = "proxy-cache", }) do
-        if err then
-          return kong.response.exit(500, { message = err })
-        end
+      for plugin in each_proxy_cache() do
 
         local strategy = require(STRATEGY_PATH)({
           strategy_name = plugin.config.strategy,

spec/03-api_spec.lua

@@ -24,6 +24,13 @@ describe("Plugin: proxy-cache", function()
       },
     })
 
+    -- an additional plugin does not interfere with the iteration in
+    -- the global /proxy-cache API handler: regression test for
+    -- https://github.com/Kong/kong-plugin-proxy-cache/issues/12
+    assert(bp.plugins:insert {
+      name = "request-transformer",
+    })
+
     local route2 = assert(bp.routes:insert {
       hosts = { "route-2.com" },
     })
@@ -41,7 +48,7 @@ describe("Plugin: proxy-cache", function()
     })
 
     assert(helpers.start_kong({
-      plugins = "proxy-cache",
+      plugins = "proxy-cache,request-transformer",
       nginx_conf = "spec/fixtures/custom_nginx.template",
     }))