From 41e7b28249eafa9ede2dac96bdb6f73e8d8482ee Mon Sep 17 00:00:00 2001
From: samugi <samuele@konghq.com>
Date: Tue, 25 Jun 2024 12:52:35 +0200
Subject: [PATCH] fixup! feat(observability): add OpenTelemetry logs

---
 kong/globalpatches.lua                 | 13 ++++++++++++-
 kong/observability/logs.lua            | 12 +++---------
 kong/plugins/opentelemetry/handler.lua |  2 +-
 kong/plugins/opentelemetry/logs.lua    |  7 -------
 kong/runloop/plugins_iterator.lua      |  6 ++++++
 5 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/kong/globalpatches.lua b/kong/globalpatches.lua
index 784a272006da..ada730c64b3c 100644
--- a/kong/globalpatches.lua
+++ b/kong/globalpatches.lua
@@ -593,7 +593,15 @@ return function(options)
 
     -- OTel-formatted logs feature
     local dynamic_hook = require "kong.dynamic_hook"
+    local log_called = false
     _G.ngx.log = function(...)
+      if log_called then
+        -- avoid recursive loops
+        -- relies on the patch to NOT yield
+        return old_ngx_log(...)
+      end
+      log_called = true
+
       -- stack level = 5:
       -- 1: maybe_push
       -- 2: dynamic_hook.pcall
@@ -601,9 +609,12 @@ return function(options)
       -- 4: patched function
       -- 5: caller
       dynamic_hook.run_hook("observability_logs", "push", 5, ...)
-
+      log_called = false
       return old_ngx_log(...)
     end
+    -- export native ngx.log to be used where
+    -- the patched code must not be executed
+    _G.native_ngx_log = old_ngx_log
 
     if not options.cli and not options.rbusted then
       local timing = require "kong.timing"
diff --git a/kong/observability/logs.lua b/kong/observability/logs.lua
index d0b715c5e7d1..11a84f046208 100644
--- a/kong/observability/logs.lua
+++ b/kong/observability/logs.lua
@@ -104,18 +104,12 @@ end
 
 
 function _M.maybe_push(stack_level, log_level, ...)
-  -- !WARNING! no logging here, to avoid infinite recursion.
-  --
-  -- Check if this log entry is eligible to go in the log buffer.
+  -- WARNING: do not yield in this function, as it is called from ngx.log
+
   -- Early return cases:
 
-  -- no log line
+  -- no (or empty) log line
   local args = { ... }
-  if #args == 0 then
-    return
-  end
-
-  -- empty log line
   local log_str = concat_tostring(args)
   if log_str == "" then
     return
diff --git a/kong/plugins/opentelemetry/handler.lua b/kong/plugins/opentelemetry/handler.lua
index 49d8b49cbffb..7d7d19adfd3d 100644
--- a/kong/plugins/opentelemetry/handler.lua
+++ b/kong/plugins/opentelemetry/handler.lua
@@ -17,7 +17,7 @@ function OpenTelemetryHandler:configure(configs)
     for _, config in ipairs(configs) do
       if config.logs_endpoint then
         dynamic_hook.hook("observability_logs", "push", o11y_logs.maybe_push)
-        dynamic_hook.always_enable("observability_logs")
+        dynamic_hook.enable_by_default("observability_logs")
       end
     end
   end
diff --git a/kong/plugins/opentelemetry/logs.lua b/kong/plugins/opentelemetry/logs.lua
index 0fc1e34d6afd..ac254326205e 100644
--- a/kong/plugins/opentelemetry/logs.lua
+++ b/kong/plugins/opentelemetry/logs.lua
@@ -1,10 +1,3 @@
--- This software is copyright Kong Inc. and its licensors.
--- Use of the software is subject to the agreement between your organization
--- and Kong Inc. If there is no such agreement, use is governed by and
--- subject to the terms of the Kong Master Software License Agreement found
--- at https://konghq.com/enterprisesoftwarelicense/.
--- [ END OF LICENSE 0867164ffc95e54f04670b5169c09574bdbd9bba ]
-
 local Queue = require "kong.tools.queue"
 local o11y_logs = require "kong.observability.logs"
 local otlp = require "kong.plugins.opentelemetry.otlp"
diff --git a/kong/runloop/plugins_iterator.lua b/kong/runloop/plugins_iterator.lua
index 6fe558004035..78a6421011a6 100644
--- a/kong/runloop/plugins_iterator.lua
+++ b/kong/runloop/plugins_iterator.lua
@@ -1,6 +1,7 @@
 local workspaces = require "kong.workspaces"
 local constants = require "kong.constants"
 local tablepool = require "tablepool"
+local req_dyn_hook = require "kong.dynamic_hook"
 
 
 local kong = kong
@@ -17,6 +18,7 @@ local fetch_table = tablepool.fetch
 local release_table = tablepool.release
 local uuid = require("kong.tools.uuid").uuid
 local get_updated_monotonic_ms = require("kong.tools.time").get_updated_monotonic_ms
+local req_dyn_hook_disable_by_default = req_dyn_hook.disable_by_default
 
 
 local TTL_ZERO = { ttl = 0 }
@@ -428,6 +430,10 @@ end
 
 
 local function configure(configurable, ctx)
+  -- Disable hooks that are selectively enabled by plugins
+  -- in their :configure handler
+  req_dyn_hook_disable_by_default("observability_logs")
+
   ctx = ctx or ngx.ctx
   local kong_global = require "kong.global"
   for _, plugin in ipairs(CONFIGURABLE_PLUGINS) do