From 0d7a1247b3817015e7f82c2b2f399dd774bc6125 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 06:31:54 +0800
Subject: [PATCH 01/19] version is string

---
 kong/clustering/services/sync/strategies/postgres.lua | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index 7bc0784c6e6..a6290ab4946 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -2,6 +2,7 @@ local _M = {}
 local _MT = { __index = _M }
 
 
+local fmt = string.format
 local ngx_null = ngx.null
 
 
@@ -44,10 +45,10 @@ function _M:get_latest_version()
 
   local ver = res[1] and res[1].max
   if ver == ngx_null then
-    return 0
+    return fmt("%032d", 0)
   end
 
-  return ver
+  return fmt("%032d", ver)
 end
 
 

From 5a9acc61305959cee25d30c70bc2b82590de18c3 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 09:59:17 +0800
Subject: [PATCH 02/19] change version usage

---
 kong/clustering/services/sync/rpc.lua | 26 +++++++++++++-------------
 kong/db/declarative/import.lua        |  2 +-
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index c84a10ecd76..a192dcc356f 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -14,6 +14,7 @@ local insert_entity_for_txn = declarative.insert_entity_for_txn
 local delete_entity_for_txn = declarative.delete_entity_for_txn
 local DECLARATIVE_HASH_KEY = constants.DECLARATIVE_HASH_KEY
 local CLUSTERING_DATA_PLANES_LATEST_VERSION_KEY = constants.CLUSTERING_DATA_PLANES_LATEST_VERSION_KEY
+local DECLARATIVE_EMPTY_CONFIG_HASH = constants.DECLARATIVE_EMPTY_CONFIG_HASH
 local DECLARATIVE_DEFAULT_WORKSPACE_KEY = constants.DECLARATIVE_DEFAULT_WORKSPACE_KEY
 local CLUSTERING_SYNC_STATUS = constants.CLUSTERING_SYNC_STATUS
 local SYNC_MUTEX_OPTS = { name = "get_delta", timeout = 0, }
@@ -22,7 +23,6 @@ local MAX_RETRY = 5
 
 local assert = assert
 local ipairs = ipairs
-local fmt = string.format
 local ngx_null = ngx.null
 local ngx_log = ngx.log
 local ngx_ERR = ngx.ERR
@@ -60,7 +60,7 @@ function _M:init_cp(manager)
   -- CP
   -- Method: kong.sync.v2.get_delta
   -- Params: versions: list of current versions of the database
-  -- example: { default = { version = 1000, }, }
+  -- example: { default = { version = "1000", }, }
   manager.callbacks:register("kong.sync.v2.get_delta", function(node_id, current_versions)
     ngx_log(ngx_DEBUG, "[kong.sync.v2] config push (connected client)")
 
@@ -75,7 +75,7 @@ function _M:init_cp(manager)
       return nil, "default namespace does not exist inside params"
     end
 
-    -- { default = { version = 1000, }, }
+    -- { default = { version = "1000", }, }
     local default_namespace_version = default_namespace.version
     local node_info = assert(kong.rpc:get_peer_info(node_id))
 
@@ -88,7 +88,7 @@ function _M:init_cp(manager)
       labels = node_info.labels,    -- get from rpc call
       cert_details = node_info.cert_details,  -- get from rpc call
       sync_status = CLUSTERING_SYNC_STATUS.NORMAL,
-      config_hash = fmt("%032d", default_namespace_version),
+      config_hash = default_namespace_version,
       rpc_capabilities = rpc_peers and rpc_peers[node_id] or {},
     }, { ttl = purge_delay, no_broadcast_crud_event = true, })
     if not ok then
@@ -100,7 +100,7 @@ function _M:init_cp(manager)
       return nil, err
     end
 
-    if default_namespace_version == 0 or
+    if default_namespace_version == DECLARATIVE_EMPTY_CONFIG_HASH or
        default_namespace_version < latest_version then
       return full_sync_result()
     end
@@ -115,7 +115,7 @@ function _M:init_dp(manager)
   -- DP
   -- Method: kong.sync.v2.notify_new_version
   -- Params: new_versions: list of namespaces and their new versions, like:
-  -- { default = { new_version = 1000, }, }
+  -- { default = { new_version = "1000", }, }
   manager.callbacks:register("kong.sync.v2.notify_new_version", function(node_id, new_versions)
     -- TODO: currently only default is supported, and anything else is ignored
     local default_new_version = new_versions.default
@@ -128,7 +128,7 @@ function _M:init_dp(manager)
       return nil, "'new_version' key does not exist"
     end
 
-    local lmdb_ver = tonumber(declarative.get_current_hash()) or 0
+    local lmdb_ver = declarative.get_current_hash()
     if lmdb_ver < version then
       -- set lastest version to shm
       kong_shm:set(CLUSTERING_DATA_PLANES_LATEST_VERSION_KEY, version)
@@ -174,7 +174,7 @@ local function do_sync()
 
   local msg = { default =
                  { version =
-                   tonumber(declarative.get_current_hash()) or 0,
+                   declarative.get_current_hash(),
                  },
                }
 
@@ -226,13 +226,13 @@ local function do_sync()
 
   local db = kong.db
 
-  local version = 0
+  local version = ""
   local opts = {}
   local crud_events = {}
   local crud_events_n = 0
 
   -- delta should look like:
-  -- { type = ..., entity = { ... }, version = 1, ws_id = ..., }
+  -- { type = ..., entity = { ... }, version = "1", ws_id = ..., }
   for _, delta in ipairs(deltas) do
     local delta_version = delta.version
     local delta_type = delta.type
@@ -308,7 +308,7 @@ local function do_sync()
     end
 
     -- delta.version should not be nil or ngx.null
-    assert(type(delta_version) == "number")
+    assert(type(delta_version) == "string")
 
     if delta_version ~= version then
       version = delta_version
@@ -316,7 +316,7 @@ local function do_sync()
   end -- for _, delta
 
   -- store current sync version
-  t:set(DECLARATIVE_HASH_KEY, fmt("%032d", version))
+  t:set(DECLARATIVE_HASH_KEY, version)
 
   -- store the correct default workspace uuid
   if default_ws_changed then
@@ -391,7 +391,7 @@ function sync_once_impl(premature, retry_count)
     return
   end
 
-  local current_version = tonumber(declarative.get_current_hash()) or 0
+  local current_version = declarative.get_current_hash()
   if current_version >= latest_notified_version then
     ngx_log(ngx_DEBUG, "version already updated")
     return
diff --git a/kong/db/declarative/import.lua b/kong/db/declarative/import.lua
index 1b2bfc72713..d502b550bc8 100644
--- a/kong/db/declarative/import.lua
+++ b/kong/db/declarative/import.lua
@@ -231,7 +231,7 @@ end
 
 
 local function get_current_hash()
-  return lmdb.get(DECLARATIVE_HASH_KEY)
+  return lmdb.get(DECLARATIVE_HASH_KEY) or DECLARATIVE_EMPTY_CONFIG_HASH
 end
 
 

From 46b6747f35cb7f162f99135f471e1a6f0778bbf1 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 10:08:51 +0800
Subject: [PATCH 03/19] clean

---
 kong/clustering/services/sync/rpc.lua | 6 +++---
 kong/db/declarative/import.lua        | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index a192dcc356f..6cc8835b485 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -128,7 +128,7 @@ function _M:init_dp(manager)
       return nil, "'new_version' key does not exist"
     end
 
-    local lmdb_ver = declarative.get_current_hash()
+    local lmdb_ver = declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH
     if lmdb_ver < version then
       -- set lastest version to shm
       kong_shm:set(CLUSTERING_DATA_PLANES_LATEST_VERSION_KEY, version)
@@ -174,7 +174,7 @@ local function do_sync()
 
   local msg = { default =
                  { version =
-                   declarative.get_current_hash(),
+                   declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH,
                  },
                }
 
@@ -391,7 +391,7 @@ function sync_once_impl(premature, retry_count)
     return
   end
 
-  local current_version = declarative.get_current_hash()
+  local current_version = declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH
   if current_version >= latest_notified_version then
     ngx_log(ngx_DEBUG, "version already updated")
     return
diff --git a/kong/db/declarative/import.lua b/kong/db/declarative/import.lua
index d502b550bc8..1b2bfc72713 100644
--- a/kong/db/declarative/import.lua
+++ b/kong/db/declarative/import.lua
@@ -231,7 +231,7 @@ end
 
 
 local function get_current_hash()
-  return lmdb.get(DECLARATIVE_HASH_KEY) or DECLARATIVE_EMPTY_CONFIG_HASH
+  return lmdb.get(DECLARATIVE_HASH_KEY)
 end
 
 

From 20e10f161305b0d8da9d6000320889df49f12959 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 10:30:33 +0800
Subject: [PATCH 04/19] fix 05-sync-rpc_spec.lua

---
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index 26aa9b4b5b1..ab97d6008de 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -1,3 +1,4 @@
+local constants = require("kong.constants")
 local helpers = require("spec.helpers")
 local misc = require("spec.internal.misc")
 local cp = require("spec.helpers.rpc_mock.cp")
@@ -5,6 +6,7 @@ local dp = require("spec.helpers.rpc_mock.dp")
 local setup = require("spec.helpers.rpc_mock.setup")
 local get_node_id = misc.get_node_id
 local DP_PREFIX = "servroot_dp"
+local DECLARATIVE_EMPTY_CONFIG_HASH = constants.DECLARATIVE_EMPTY_CONFIG_HASH
 
 local function change_config()
   -- the initial sync is flaky. let's trigger a sync by creating a service
@@ -74,12 +76,12 @@ describe("kong.sync.v2", function()
       local called = false
       mocked_cp:mock("kong.sync.v2.get_delta", function(node_id, payload)
         called = true
-        return { default = { version = 100, deltas = {} } }
+        return { default = { version = "100", deltas = {} } }
       end)
 
       -- make a call from the mocked cp
       -- CP->DP: notify_new_version
-      assert(mocked_cp:call(node_id, "kong.sync.v2.notify_new_version", { default = { new_version = 100, } }))
+      assert(mocked_cp:call(node_id, "kong.sync.v2.notify_new_version", { default = { new_version = "100", } }))
 
       -- DP->CP: get_delta
       -- the dp after receiving the notification will make a call to the cp
@@ -120,7 +122,7 @@ describe("kong.sync.v2", function()
       -- this is a workaround to registers the data plane node
       -- CP does not register the DP node until it receives a call from the DP
       function register_dp()
-        local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = 0,},})
+        local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = "0",},})
         assert.is_nil(err)
         assert.is_table(res and res.default and res.default.deltas)
       end
@@ -132,7 +134,7 @@ describe("kong.sync.v2", function()
     end)
 
     it("rpc call", function()
-      local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = 0,},})
+      local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = "0",},})
       assert.is_nil(err)
       assert.is_table(res and res.default and res.default.deltas)
 

From 2cd7d4f9a1987b2541b9692197ab6addf0a4246e Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 10:31:16 +0800
Subject: [PATCH 05/19] clean

---
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 2 --
 1 file changed, 2 deletions(-)

diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index ab97d6008de..bd992c38ccc 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -1,4 +1,3 @@
-local constants = require("kong.constants")
 local helpers = require("spec.helpers")
 local misc = require("spec.internal.misc")
 local cp = require("spec.helpers.rpc_mock.cp")
@@ -6,7 +5,6 @@ local dp = require("spec.helpers.rpc_mock.dp")
 local setup = require("spec.helpers.rpc_mock.setup")
 local get_node_id = misc.get_node_id
 local DP_PREFIX = "servroot_dp"
-local DECLARATIVE_EMPTY_CONFIG_HASH = constants.DECLARATIVE_EMPTY_CONFIG_HASH
 
 local function change_config()
   -- the initial sync is flaky. let's trigger a sync by creating a service

From 0de82277e91af66a24dd0a2a20d52e760828f723 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 12:35:09 +0800
Subject: [PATCH 06/19] fix tests

---
 .../18-hybrid_rpc/05-sync-rpc_spec.lua            | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index bd992c38ccc..ed6dad45493 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -6,6 +6,13 @@ local setup = require("spec.helpers.rpc_mock.setup")
 local get_node_id = misc.get_node_id
 local DP_PREFIX = "servroot_dp"
 
+
+-- now version must be a string
+local function fmt(v)
+  return string.format("%032d", v)
+end
+
+
 local function change_config()
   -- the initial sync is flaky. let's trigger a sync by creating a service
   local admin_client = helpers.admin_client()
@@ -74,12 +81,12 @@ describe("kong.sync.v2", function()
       local called = false
       mocked_cp:mock("kong.sync.v2.get_delta", function(node_id, payload)
         called = true
-        return { default = { version = "100", deltas = {} } }
+        return { default = { version = fmt(100), deltas = {} } }
       end)
 
       -- make a call from the mocked cp
       -- CP->DP: notify_new_version
-      assert(mocked_cp:call(node_id, "kong.sync.v2.notify_new_version", { default = { new_version = "100", } }))
+      assert(mocked_cp:call(node_id, "kong.sync.v2.notify_new_version", { default = { new_version = fmt(100), } }))
 
       -- DP->CP: get_delta
       -- the dp after receiving the notification will make a call to the cp
@@ -120,7 +127,7 @@ describe("kong.sync.v2", function()
       -- this is a workaround to registers the data plane node
       -- CP does not register the DP node until it receives a call from the DP
       function register_dp()
-        local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = "0",},})
+        local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = fmt(0),},})
         assert.is_nil(err)
         assert.is_table(res and res.default and res.default.deltas)
       end
@@ -132,7 +139,7 @@ describe("kong.sync.v2", function()
     end)
 
     it("rpc call", function()
-      local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = "0",},})
+      local res, err = mocked_dp:call("control_plane", "kong.sync.v2.get_delta", { default = { version = fmt(0),},})
       assert.is_nil(err)
       assert.is_table(res and res.default and res.default.deltas)
 

From 6bd7ecd3839a6e8cfd7c0d81fc4ee3f1b692e935 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 12:41:30 +0800
Subject: [PATCH 07/19] VERSION_FMT

---
 kong/clustering/services/sync/strategies/postgres.lua  | 9 +++++++--
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index a6290ab4946..f46904de212 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -6,6 +6,11 @@ local fmt = string.format
 local ngx_null = ngx.null
 
 
+-- version string should be greater than any hex string(ngx.md5)
+-- e.g.: "R000" > "FFFF"
+local VERSION_FMT = "R%031d"
+
+
 function _M.new(db)
   local self = {
     connector = db.connector,
@@ -45,10 +50,10 @@ function _M:get_latest_version()
 
   local ver = res[1] and res[1].max
   if ver == ngx_null then
-    return fmt("%032d", 0)
+    return fmt(VERSION_FMT, 0)
   end
 
-  return fmt("%032d", ver)
+  return fmt(VERSION_FMT, ver)
 end
 
 
diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index ed6dad45493..a8b3638bdf5 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -9,7 +9,7 @@ local DP_PREFIX = "servroot_dp"
 
 -- now version must be a string
 local function fmt(v)
-  return string.format("%032d", v)
+  return string.format("R%031d", v)
 end
 
 

From 4e92824b78bc1d7c382e1e3b1eda42b9bd91a4b9 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 13:03:54 +0800
Subject: [PATCH 08/19] get_current_hash

---
 kong/clustering/services/sync/rpc.lua | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 6cc8835b485..15472133665 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -54,6 +54,11 @@ local function full_sync_result()
 end
 
 
+local function get_current_hash()
+  return declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH
+end
+
+
 function _M:init_cp(manager)
   local purge_delay = manager.conf.cluster_data_plane_purge_delay
 
@@ -128,7 +133,7 @@ function _M:init_dp(manager)
       return nil, "'new_version' key does not exist"
     end
 
-    local lmdb_ver = declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH
+    local lmdb_ver = get_current_hash()
     if lmdb_ver < version then
       -- set lastest version to shm
       kong_shm:set(CLUSTERING_DATA_PLANES_LATEST_VERSION_KEY, version)
@@ -172,11 +177,7 @@ local function do_sync()
     return nil, "rpc is not ready"
   end
 
-  local msg = { default =
-                 { version =
-                   declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH,
-                 },
-               }
+  local msg = { default = { version = get_current_hash(), }, }
 
   local ns_deltas, err = kong.rpc:call("control_plane", "kong.sync.v2.get_delta", msg)
   if not ns_deltas then
@@ -391,7 +392,7 @@ function sync_once_impl(premature, retry_count)
     return
   end
 
-  local current_version = declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH
+  local current_version = get_current_hash()
   if current_version >= latest_notified_version then
     ngx_log(ngx_DEBUG, "version already updated")
     return

From 8d8b89cef10dad6f153b1f63308e4a53043cc796 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 13:05:55 +0800
Subject: [PATCH 09/19] get_current_version

---
 kong/clustering/services/sync/rpc.lua | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 15472133665..d6e6f295ba6 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -54,7 +54,7 @@ local function full_sync_result()
 end
 
 
-local function get_current_hash()
+local function get_current_version()
   return declarative.get_current_hash() or DECLARATIVE_EMPTY_CONFIG_HASH
 end
 
@@ -133,7 +133,7 @@ function _M:init_dp(manager)
       return nil, "'new_version' key does not exist"
     end
 
-    local lmdb_ver = get_current_hash()
+    local lmdb_ver = get_current_version()
     if lmdb_ver < version then
       -- set lastest version to shm
       kong_shm:set(CLUSTERING_DATA_PLANES_LATEST_VERSION_KEY, version)
@@ -177,7 +177,7 @@ local function do_sync()
     return nil, "rpc is not ready"
   end
 
-  local msg = { default = { version = get_current_hash(), }, }
+  local msg = { default = { version = get_current_version(), }, }
 
   local ns_deltas, err = kong.rpc:call("control_plane", "kong.sync.v2.get_delta", msg)
   if not ns_deltas then
@@ -392,7 +392,7 @@ function sync_once_impl(premature, retry_count)
     return
   end
 
-  local current_version = get_current_hash()
+  local current_version = get_current_version()
   if current_version >= latest_notified_version then
     ngx_log(ngx_DEBUG, "version already updated")
     return

From 7b8bc6f269da200fae6165b2db1aebfc0848deed Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 3 Jan 2025 13:07:52 +0800
Subject: [PATCH 10/19] is_empty_version

---
 kong/clustering/services/sync/rpc.lua | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index d6e6f295ba6..ef83aa273e5 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -59,6 +59,11 @@ local function get_current_version()
 end
 
 
+local function is_empty_version(v)
+  return v == DECLARATIVE_EMPTY_CONFIG_HASH
+end
+
+
 function _M:init_cp(manager)
   local purge_delay = manager.conf.cluster_data_plane_purge_delay
 
@@ -105,7 +110,7 @@ function _M:init_cp(manager)
       return nil, err
     end
 
-    if default_namespace_version == DECLARATIVE_EMPTY_CONFIG_HASH or
+    if is_empty_version(default_namespace_version) or
        default_namespace_version < latest_version then
       return full_sync_result()
     end

From 3190c9daf515f2f74603432c67c2bdc85eba6e92 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Mon, 6 Jan 2025 10:44:35 +0800
Subject: [PATCH 11/19] is_empty_version

---
 kong/clustering/services/sync/rpc.lua | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index ef83aa273e5..911285793d7 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -59,8 +59,15 @@ local function get_current_version()
 end
 
 
-local function is_empty_version(v)
-  return v == DECLARATIVE_EMPTY_CONFIG_HASH
+local is_empty_version
+do
+  local byte = string.byte
+  local CHAR_R = byte("R")
+
+  -- version string must start with char 'R'
+  is_empty_version = function(v)
+    return byte(v) ~= CHAR_R
+  end
 end
 
 

From 98d9c094b41bf4a86649fb1708c89cb641968152 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Mon, 6 Jan 2025 11:15:48 +0800
Subject: [PATCH 12/19] prefix V

---
 kong/clustering/services/sync/rpc.lua                  | 6 +++---
 kong/clustering/services/sync/strategies/postgres.lua  | 4 ++--
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 911285793d7..035aed2c8a1 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -62,11 +62,11 @@ end
 local is_empty_version
 do
   local byte = string.byte
-  local CHAR_R = byte("R")
+  local CHAR_V = byte("V")
 
-  -- version string must start with char 'R'
+  -- version string must start with char 'V'
   is_empty_version = function(v)
-    return byte(v) ~= CHAR_R
+    return byte(v) ~= CHAR_V
   end
 end
 
diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index f46904de212..632f1903a96 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -7,8 +7,8 @@ local ngx_null = ngx.null
 
 
 -- version string should be greater than any hex string(ngx.md5)
--- e.g.: "R000" > "FFFF"
-local VERSION_FMT = "R%031d"
+-- e.g.: "V000" > "FFFF"
+local VERSION_FMT = "V%031d"
 
 
 function _M.new(db)
diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index a8b3638bdf5..3dfe82fceea 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -9,7 +9,7 @@ local DP_PREFIX = "servroot_dp"
 
 -- now version must be a string
 local function fmt(v)
-  return string.format("R%031d", v)
+  return string.format("V%031d", v)
 end
 
 

From f189dac232321ae59c1aaa53bc788b9751d17852 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Mon, 6 Jan 2025 15:15:42 +0800
Subject: [PATCH 13/19] is_invalid_version

---
 kong/clustering/services/sync/rpc.lua | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 035aed2c8a1..17f3e0cfaaf 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -59,13 +59,13 @@ local function get_current_version()
 end
 
 
-local is_empty_version
+local is_invalid_version
 do
   local byte = string.byte
   local CHAR_V = byte("V")
 
   -- version string must start with char 'V'
-  is_empty_version = function(v)
+  is_invalid_version = function(v)
     return byte(v) ~= CHAR_V
   end
 end
@@ -117,7 +117,8 @@ function _M:init_cp(manager)
       return nil, err
     end
 
-    if is_empty_version(default_namespace_version) or
+    --  string comparison effectively does the same as number comparison
+    if is_invalid_version(default_namespace_version) or
        default_namespace_version < latest_version then
       return full_sync_result()
     end

From 7a517d0b344245fa36615b49579bdc5feac3661f Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Mon, 6 Jan 2025 17:35:19 +0800
Subject: [PATCH 14/19] prefix is V02_

---
 kong/clustering/services/sync/rpc.lua                  | 8 ++++----
 kong/clustering/services/sync/strategies/postgres.lua  | 4 ++--
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 17f3e0cfaaf..db54f3d2475 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -61,12 +61,12 @@ end
 
 local is_invalid_version
 do
-  local byte = string.byte
-  local CHAR_V = byte("V")
+  local sub = string.sub
+  local VER_PREFIX = "V02_"
 
-  -- version string must start with char 'V'
+  -- version string must start with 'V02_'
   is_invalid_version = function(v)
-    return byte(v) ~= CHAR_V
+    return sub(v, 1, 4) ~= VER_PREFIX
   end
 end
 
diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index 632f1903a96..f74ea71206c 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -7,8 +7,8 @@ local ngx_null = ngx.null
 
 
 -- version string should be greater than any hex string(ngx.md5)
--- e.g.: "V000" > "FFFF"
-local VERSION_FMT = "V%031d"
+-- e.g.: "V02_0000" > "FFFFFFFF"
+local VERSION_FMT = "V02_%028d"
 
 
 function _M.new(db)
diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index 3dfe82fceea..d3780b2ed12 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -9,7 +9,7 @@ local DP_PREFIX = "servroot_dp"
 
 -- now version must be a string
 local function fmt(v)
-  return string.format("V%031d", v)
+  return string.format("V02_%028d", v)
 end
 
 

From 89865aeed6b70e2f9eceebb781c4a06e00c029c1 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Mon, 6 Jan 2025 17:37:51 +0800
Subject: [PATCH 15/19] is_valid_version

---
 kong/clustering/services/sync/rpc.lua | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index db54f3d2475..a3873950db3 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -59,14 +59,14 @@ local function get_current_version()
 end
 
 
-local is_invalid_version
+local is_valid_version
 do
   local sub = string.sub
   local VER_PREFIX = "V02_"
 
   -- version string must start with 'V02_'
-  is_invalid_version = function(v)
-    return sub(v, 1, 4) ~= VER_PREFIX
+  is_valid_version = function(v)
+    return sub(v, 1, 4) == VER_PREFIX
   end
 end
 
@@ -118,7 +118,7 @@ function _M:init_cp(manager)
     end
 
     --  string comparison effectively does the same as number comparison
-    if is_invalid_version(default_namespace_version) or
+    if not is_valid_version(default_namespace_version) or
        default_namespace_version < latest_version then
       return full_sync_result()
     end

From 608ba4dd8fd2fba8253e525895db513d2b55d1e2 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Wed, 8 Jan 2025 07:01:21 +0800
Subject: [PATCH 16/19] clean

---
 kong/clustering/services/sync/rpc.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index a3873950db3..9af63560ad9 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -23,6 +23,7 @@ local MAX_RETRY = 5
 
 local assert = assert
 local ipairs = ipairs
+local sub = string.sub
 local ngx_null = ngx.null
 local ngx_log = ngx.log
 local ngx_ERR = ngx.ERR
@@ -61,7 +62,6 @@ end
 
 local is_valid_version
 do
-  local sub = string.sub
   local VER_PREFIX = "V02_"
 
   -- version string must start with 'V02_'

From 240beb4110f89862b213a7347c66f7972977d902 Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Wed, 8 Jan 2025 10:29:10 +0800
Subject: [PATCH 17/19] change to v02

---
 kong/clustering/services/sync/rpc.lua                  | 4 ++--
 kong/clustering/services/sync/strategies/postgres.lua  | 4 ++--
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kong/clustering/services/sync/rpc.lua b/kong/clustering/services/sync/rpc.lua
index 9af63560ad9..cd1db7fe75c 100644
--- a/kong/clustering/services/sync/rpc.lua
+++ b/kong/clustering/services/sync/rpc.lua
@@ -62,9 +62,9 @@ end
 
 local is_valid_version
 do
-  local VER_PREFIX = "V02_"
+  local VER_PREFIX = "v02_"
 
-  -- version string must start with 'V02_'
+  -- version string must start with 'v02_'
   is_valid_version = function(v)
     return sub(v, 1, 4) == VER_PREFIX
   end
diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index f74ea71206c..b7cbe4830d2 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -7,8 +7,8 @@ local ngx_null = ngx.null
 
 
 -- version string should be greater than any hex string(ngx.md5)
--- e.g.: "V02_0000" > "FFFFFFFF"
-local VERSION_FMT = "V02_%028d"
+-- e.g.: "v02_0000" > "FFFFFFFF"
+local VERSION_FMT = "v02_%028d"
 
 
 function _M.new(db)
diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index d3780b2ed12..5137ca5574a 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -9,7 +9,7 @@ local DP_PREFIX = "servroot_dp"
 
 -- now version must be a string
 local function fmt(v)
-  return string.format("V02_%028d", v)
+  return string.format("v02_%028d", v)
 end
 
 

From 4f0db45e1126a8a045095420a9dd15aec84a42fe Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 10 Jan 2025 16:28:43 +0800
Subject: [PATCH 18/19] format hex

---
 kong/clustering/services/sync/strategies/postgres.lua  | 2 +-
 spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index b7cbe4830d2..2c2f7a37047 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -8,7 +8,7 @@ local ngx_null = ngx.null
 
 -- version string should be greater than any hex string(ngx.md5)
 -- e.g.: "v02_0000" > "FFFFFFFF"
-local VERSION_FMT = "v02_%028d"
+local VERSION_FMT = "v02_%028x"
 
 
 function _M.new(db)
diff --git a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
index 5137ca5574a..c9559c6601d 100644
--- a/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
+++ b/spec/02-integration/18-hybrid_rpc/05-sync-rpc_spec.lua
@@ -9,7 +9,7 @@ local DP_PREFIX = "servroot_dp"
 
 -- now version must be a string
 local function fmt(v)
-  return string.format("v02_%028d", v)
+  return string.format("v02_%028x", v)
 end
 
 

From c84e5320484f098a082af425af2033b85603010c Mon Sep 17 00:00:00 2001
From: chronolaw <chrono_cpp@me.com>
Date: Fri, 10 Jan 2025 16:58:42 +0800
Subject: [PATCH 19/19] update comment

---
 kong/clustering/services/sync/strategies/postgres.lua | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kong/clustering/services/sync/strategies/postgres.lua b/kong/clustering/services/sync/strategies/postgres.lua
index 2c2f7a37047..20e594d92f3 100644
--- a/kong/clustering/services/sync/strategies/postgres.lua
+++ b/kong/clustering/services/sync/strategies/postgres.lua
@@ -6,8 +6,7 @@ local fmt = string.format
 local ngx_null = ngx.null
 
 
--- version string should be greater than any hex string(ngx.md5)
--- e.g.: "v02_0000" > "FFFFFFFF"
+-- version string should look like: "v02_0000"
 local VERSION_FMT = "v02_%028x"