feat(core) upstreams (#1735)

* adds loadbalancing on specified targets
* adds service registry
* implements #157
* adds entities: upstreams and targets
* modifies timestamps to millisecond precision (except for the non-related tables when using postgres)
* adds collecting health-data on a per-request basis (unused for now)

kong/core/hooks.lua

@@ -46,6 +46,19 @@ local function invalidate(message_t)
 
   elseif message_t.collection == "ssl_servers_names" then
     cache.delete(cache.certificate_key(message_t.entity.name))
+
+  elseif message_t.collection == "targets" then
+    -- targets only append new entries, we're not changing anything
+    -- but we need to reload the related upstreams target-history, so invalidate
+    -- that instead of the target
+    cache.delete(cache.targets_key(message_t.entity.upstream_id))
+
+  elseif message_t.collection == "upstreams" then
+    --we invalidate the list, the individual upstream, and its target history
+    cache.delete(cache.upstreams_dict_key())
+    cache.delete(cache.upstream_key(message_t.entity.id))
+    cache.delete(cache.targets_key(message_t.entity.id))
+    balancer.invalidate_balancer(message_t.entity.name)
   end
 end
 

kong/dao/migrations/cassandra.lua

@@ -307,5 +307,39 @@ return {
       ALTER TABLE apis DROP https_only;
       ALTER TABLE apis DROP http_if_terminated;
     ]]
-  }
+  },
+  {
+    name = "2016-09-16-141423_upstreams",
+    -- Note on the timestamps;
+    -- The Cassandra timestamps are created in Lua code, and hence ALL entities
+    -- will now be created in millisecond precision. The existing entries will
+    -- remain in second precision, but new ones (for ALL entities!) will be
+    -- in millisecond precision.
+    -- This differs from the Postgres one where only the new entities (upstreams
+    -- and targets) will get millisecond precision.
+    up = [[
+      CREATE TABLE IF NOT EXISTS upstreams(
+        id uuid,
+        name text,
+        slots int,
+        orderlist text,
+        created_at timestamp,
+        PRIMARY KEY (id)
+      );
+      CREATE INDEX IF NOT EXISTS ON upstreams(name);
+      CREATE TABLE IF NOT EXISTS targets(
+        id uuid,
+        target text,
+        weight int,
+        upstream_id uuid,
+        created_at timestamp,
+        PRIMARY KEY (id)
+      );
+      CREATE INDEX IF NOT EXISTS ON targets(upstream_id);
+    ]],
+    down = [[
+      DROP TABLE upstreams;
+      DROP TABLE targets;
+    ]],
+  },
 }

kong/dao/migrations/postgres.lua

@@ -297,4 +297,42 @@ return {
       ALTER TABLE apis DROP COLUMN IF EXISTS http_if_terminated;
     ]]
   },
+  {
+    name = "2016-09-16-141423_upstreams",
+    -- Note on the timestamps below; these use a precision of milliseconds
+    -- this differs from the other tables above, as they only use second precision.
+    -- This differs from the change to the Cassandra entities.
+    up = [[
+      CREATE TABLE IF NOT EXISTS upstreams(
+        id uuid PRIMARY KEY,
+        name text UNIQUE,
+        slots int NOT NULL,
+        orderlist text NOT NULL,
+        created_at timestamp without time zone default (CURRENT_TIMESTAMP(3) at time zone 'utc')
+      );
+      DO $$
+      BEGIN
+        IF (SELECT to_regclass('upstreams_name_idx')) IS NULL THEN
+          CREATE INDEX upstreams_name_idx ON upstreams(name);
+        END IF;
+      END$$;
+      CREATE TABLE IF NOT EXISTS targets(
+        id uuid PRIMARY KEY,
+        target text NOT NULL,
+        weight int NOT NULL,
+        upstream_id uuid REFERENCES upstreams(id) ON DELETE CASCADE,
+        created_at timestamp without time zone default (CURRENT_TIMESTAMP(3) at time zone 'utc')
+      );
+      DO $$
+      BEGIN
+        IF (SELECT to_regclass('targets_target_idx')) IS NULL THEN
+          CREATE INDEX targets_target_idx ON targets(target);
+        END IF;
+      END$$;
+    ]],
+    down = [[
+      DROP TABLE upstreams;
+      DROP TABLE targets;
+    ]],
+  },
 }