feat(key-auth) support auto-expiring keys

Fixes #87.

kong/plugins/key-auth/daos.lua

@@ -2,6 +2,7 @@ local typedefs = require "kong.db.schema.typedefs"
 
 return {
   keyauth_credentials = {
+    ttl = true,
     primary_key = { "id" },
     name = "keyauth_credentials",
     endpoint_key = "key",

kong/plugins/key-auth/migrations/002_130_to_140.lua

@@ -27,6 +27,13 @@ return {
         -- Do nothing, accept existing state
       END$$;
 
+      DO $$
+      BEGIN
+        ALTER TABLE IF EXISTS ONLY "keyauth_credentials" ADD "ttl" TIMESTAMP WITH TIME ZONE;
+      EXCEPTION WHEN DUPLICATE_COLUMN THEN
+        -- Do nothing, accept existing state
+      END$$;
+
     ]],
   },
   cassandra = {

spec/03-plugins/09-key-auth/01-api_spec.lua

@@ -119,6 +119,31 @@ for _, strategy in helpers.each_strategy() do
           assert.equal("tag1", json.tags[1])
           assert.equal("tag2", json.tags[2])
         end)
+        it("creates a key-auth credential with a ttl", function()
+          local res = assert(admin_client:send {
+            method  = "POST",
+            path    = "/consumers/bob/key-auth",
+            body    = {
+              ttl = 1,
+            },
+            headers = {
+              ["Content-Type"] = "application/json"
+            }
+          })
+          local body = assert.res_status(201, res)
+          local json = cjson.decode(body)
+          assert.equal(consumer.id, json.consumer.id)
+          assert.is_string(json.key)
+
+          ngx.sleep(3)
+
+          local id = json.consumer.id
+          local res = assert(admin_client:send {
+            method  = "GET",
+            path    = "/consumers/bob/key-auth/" .. id,
+          })
+          assert.res_status(404, res)
+        end)
       end)
 
       describe("GET", function()