hotfix(migrations) fix broken upstream migrations

There exists two problems with the behavior of upstream object
migrations introduced in the 0.12.0 release:

- First, the DDL migrations to add both healthcheck and hashing
column definitions were required before executing function-level
migrations to fill in default object data. This is a result of the
current DAO implementation that requires that all Lua-schema definitions
exist as column definitions in the underlying data store, even if the
DAO update call does not reference the column in question.
- Second, the functional definitions load each row directly by a
directly underlying DB call (as opposed to a DAO find_all()); this
resulted in "table" schema types being represented as literal JSON
strings, isntead of Lua table types, by the C* driver. The Postgres
implementation does not suffer this as the underlying reprentation of
table data in Postgres-backed schemas is Postgres' JSON type; this is
automagically deserialized to a Lua table upon retrieval. As the C*
implementation offers no such behind-the-scenes transformation, a
direct load of rows containing "table" schemas results in an
incompatable data type when iterating over the returned rows. The
fix in the commit is to use the abstract DAO to load upstream rows
when leveraging C*.

Fixes #3156.

kong/dao/migrations/cassandra.lua

@@ -481,6 +481,15 @@ return {
     ]],
     down = function(_, _, dao) end  -- not implemented
   },
+  {
+    name = "2017-11-07-192000_upstream_healthchecks",
+    up = [[
+      ALTER TABLE upstreams ADD healthchecks text;
+    ]],
+    down = [[
+      ALTER TABLE upstreams DROP healthchecks;
+    ]]
+  },
   {
     name = "2017-10-27-134100_consistent_hashing_1",
     up = [[
@@ -497,7 +506,7 @@ return {
     ]]
   },
   {
-    name = "2017-10-27-134100_consistent_hashing_2",
+    name = "2017-11-07-192100_upstream_healthchecks_2",
     up = function(_, _, dao)
       local rows, err = dao.db:query([[
         SELECT * FROM upstreams;
@@ -506,54 +515,43 @@ return {
         return err
       end
 
+      local upstreams = require("kong.dao.schemas.upstreams")
+      local default = upstreams.fields.healthchecks.default
+
       for _, row in ipairs(rows) do
-        if not row.hash_on or not row.hash_fallback then
-          row.hash_on = "none"
-          row.hash_fallback = "none"
---          row.created_at = nil
-          local _, err = dao.upstreams:update(row, { id = row.id })
+        if not row.healthchecks then
+
+          local _, err = dao.upstreams:update({
+            healthchecks = default,
+          }, { id = row.id })
           if err then
             return err
           end
         end
       end
     end,
-    down = function(_, _, dao) end  -- n.a. since the columns will be dropped
-  },
-  {
-    name = "2017-11-07-192000_upstream_healthchecks",
-    up = [[
-      ALTER TABLE upstreams ADD healthchecks text;
-    ]],
-    down = [[
-      ALTER TABLE upstreams DROP healthchecks;
-    ]]
+    down = function(_, _, dao) end
   },
   {
-    name = "2017-11-07-192100_upstream_healthchecks_2",
+    name = "2017-10-27-134100_consistent_hashing_2",
     up = function(_, _, dao)
-      local rows, err = dao.db:query([[
-        SELECT * FROM upstreams;
-      ]])
+      local rows, err = dao.upstreams:find_all()
       if err then
         return err
       end
 
-      local upstreams = require("kong.dao.schemas.upstreams")
-      local default = upstreams.fields.healthchecks.default
-
       for _, row in ipairs(rows) do
-        if not row.healthchecks then
-
-          local _, err = dao.upstreams:update({
-            healthchecks = default,
-          }, { id = row.id })
+        if not row.hash_on or not row.hash_fallback then
+          row.hash_on = "none"
+          row.hash_fallback = "none"
+--          row.created_at = nil
+          local _, err = dao.upstreams:update(row, { id = row.id })
           if err then
             return err
           end
         end
       end
     end,
-    down = function(_, _, dao) end
+    down = function(_, _, dao) end  -- n.a. since the columns will be dropped
   },
 }

kong/dao/migrations/postgres.lua

@@ -542,6 +542,21 @@ return {
       ALTER TABLE apis ALTER COLUMN created_at SET DEFAULT CURRENT_TIMESTAMP(0);
     ]]
   },
+  {
+    name = "2017-11-07-192000_upstream_healthchecks",
+    up = [[
+      DO $$
+      BEGIN
+          ALTER TABLE upstreams ADD COLUMN healthchecks json;
+      EXCEPTION WHEN duplicate_column THEN
+          -- Do nothing, accept existing state
+      END$$;
+
+    ]],
+    down = [[
+      ALTER TABLE upstreams DROP COLUMN IF EXISTS healthchecks;
+    ]]
+  },
   {
     name = "2017-10-27-134100_consistent_hashing_1",
     up = [[
@@ -558,7 +573,7 @@ return {
     ]]
   },
   {
-    name = "2017-10-27-134100_consistent_hashing_2",
+    name = "2017-11-07-192100_upstream_healthchecks_2",
     up = function(_, _, dao)
       local rows, err = dao.db:query([[
         SELECT * FROM upstreams;
@@ -567,37 +582,25 @@ return {
         return err
       end
 
+      local upstreams = require("kong.dao.schemas.upstreams")
+      local default = upstreams.fields.healthchecks.default
+
       for _, row in ipairs(rows) do
-        if not row.hash_on or not row.hash_fallback then
-          row.hash_on = "none"
-          row.hash_fallback = "none"
-          row.created_at = nil
-          local _, err = dao.upstreams:update(row, { id = row.id })
+        if not row.healthchecks then
+
+          local _, err = dao.upstreams:update({
+            healthchecks = default,
+          }, { id = row.id })
           if err then
             return err
           end
         end
       end
     end,
-    down = function(_, _, dao) end  -- n.a. since the columns will be dropped
-  },
-  {
-    name = "2017-11-07-192000_upstream_healthchecks",
-    up = [[
-      DO $$
-      BEGIN
-          ALTER TABLE upstreams ADD COLUMN healthchecks json;
-      EXCEPTION WHEN duplicate_column THEN
-          -- Do nothing, accept existing state
-      END$$;
-
-    ]],
-    down = [[
-      ALTER TABLE upstreams DROP COLUMN IF EXISTS healthchecks;
-    ]]
+    down = function(_, _, dao) end
   },
   {
-    name = "2017-11-07-192100_upstream_healthchecks_2",
+    name = "2017-10-27-134100_consistent_hashing_2",
     up = function(_, _, dao)
       local rows, err = dao.db:query([[
         SELECT * FROM upstreams;
@@ -606,21 +609,18 @@ return {
         return err
       end
 
-      local upstreams = require("kong.dao.schemas.upstreams")
-      local default = upstreams.fields.healthchecks.default
-
       for _, row in ipairs(rows) do
-        if not row.healthchecks then
-
-          local _, err = dao.upstreams:update({
-            healthchecks = default,
-          }, { id = row.id })
+        if not row.hash_on or not row.hash_fallback then
+          row.hash_on = "none"
+          row.hash_fallback = "none"
+          row.created_at = nil
+          local _, err = dao.upstreams:update(row, { id = row.id })
           if err then
             return err
           end
         end
       end
     end,
-    down = function(_, _, dao) end
+    down = function(_, _, dao) end  -- n.a. since the columns will be dropped
   },
 }