[Tarantool-patches] [PATCH v8 07/12] lua/log: use log module settings inside box.cfg

[Cyrill Gorcunov]

Currently box module carries configuration settings in box.cfg
variable which is created dinamically on demand.

The default values are kept in default_cfg variable. Since we're
going to make the log module to work on its own, we need it to
provide default settings to the box.cfg interface.

For this sake we export log:box_api table which the main box
module use when needed.

Part-of #689

Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
---
 src/box/lua/load_cfg.lua | 26 ++++++++++++++----
 src/lua/log.lua          | 59 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 78 insertions(+), 7 deletions(-)

diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
index 5d818addf..7612deb90 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -59,10 +59,6 @@ local default_cfg = {
     vinyl_range_size          = nil, -- set automatically
     vinyl_page_size           = 8 * 1024,
     vinyl_bloom_fpr           = 0.05,
-    log                 = nil,
-    log_nonblock        = nil,
-    log_level           = 5,
-    log_format          = "plain",
     io_collect_interval = nil,
     readahead           = 16320,
     snap_io_rate_limit  = nil, -- no limit
@@ -233,8 +229,8 @@ end
 local dynamic_cfg = {
     listen                  = private.cfg_set_listen,
     replication             = private.cfg_set_replication,
-    log_level               = private.cfg_set_log_level,
-    log_format              = private.cfg_set_log_format,
+    log_level               = log.box_api.set_log_level,
+    log_format              = log.box_api.set_log_format,
     io_collect_interval     = private.cfg_set_io_collect_interval,
     readahead               = private.cfg_set_readahead,
     too_long_threshold      = private.cfg_set_too_long_threshold,
@@ -470,6 +466,21 @@ local function apply_default_cfg(cfg, default_cfg)
     end
 end
 
+-- Fetch default settings from modules.
+local function modules_apply_default_cfg(cfg)
+    log.box_api.on_apply_default_cfg(cfg)
+end
+
+-- Propagate settings to modules.
+local function modules_load_cfg(cfg)
+    log.box_api.on_load_cfg(cfg)
+end
+
+-- Propagate settings to modules.
+local function modules_reload_cfg(cfg)
+    log.box_api.on_reload_cfg(cfg)
+end
+
 -- Return true if two configurations are equivalent.
 local function compare_cfg(cfg1, cfg2)
     if type(cfg1) ~= type(cfg2) then
@@ -517,6 +528,7 @@ local function reload_cfg(oldcfg, cfg)
                 json.encode(val))
         end
     end
+    modules_reload_cfg(cfg)
     if type(box.on_reload_configuration) == 'function' then
         box.on_reload_configuration()
     end
@@ -554,6 +566,7 @@ local function load_cfg(cfg)
     cfg = upgrade_cfg(cfg, translate_cfg)
     cfg = prepare_cfg(cfg, default_cfg, template_cfg, modify_cfg)
     apply_default_cfg(cfg, default_cfg);
+    modules_apply_default_cfg(cfg)
     -- Save new box.cfg
     box.cfg = cfg
     if not pcall(private.cfg_check)  then
@@ -573,6 +586,7 @@ local function load_cfg(cfg)
             end,
             __call = locked(reload_cfg),
         })
+    modules_load_cfg(box.cfg)
     private.cfg_load()
     for key, fun in pairs(dynamic_cfg) do
         local val = cfg[key]
diff --git a/src/lua/log.lua b/src/lua/log.lua
index 746e0d82f..87ce313e5 100644
--- a/src/lua/log.lua
+++ b/src/lua/log.lua
@@ -101,6 +101,24 @@ local function fmt_list()
     return table.concat(keyset, ',')
 end
 
+-- Default options. The keys are part of
+-- user API, so change with caution.
+local log_cfg = {
+    log             = nil,
+    nonblock        = false,
+    level           = S_INFO,
+    format          = fmt_num2str[ffi.C.SF_PLAIN],
+}
+
+-- Name mapping from box to log module.
+-- Make sure all required fields are covered!
+local log2box_keys = {
+    ['log']         = 'log',
+    ['nonblock']    = 'log_nonblock',
+    ['level']       = 'log_level',
+    ['format']      = 'log_format',
+}
+
 local function say(level, fmt, ...)
     if ffi.C.log_level < level then
         -- don't waste cycles on debug.getinfo()
@@ -150,7 +168,8 @@ local function log_rotate()
 end
 
 local function log_level(level)
-    return ffi.C.say_set_log_level(level)
+    ffi.C.say_set_log_level(level)
+    rawset(log_cfg, 'level', level)
 end
 
 local function log_format(name)
@@ -170,12 +189,31 @@ local function log_format(name)
     else
         ffi.C.say_set_log_format(ffi.C.SF_PLAIN)
     end
+    rawset(log_cfg, 'format', name)
 end
 
 local function log_pid()
     return tonumber(ffi.C.log_pid)
 end
 
+-- Apply defaut config to the box module
+local function box_on_apply_default_cfg(box_cfg)
+    for k, v in pairs(log2box_keys) do
+        if box_cfg[v] == nil then
+            box_cfg[v] = log_cfg[k]
+        end
+    end
+end
+
+-- Update own values from box interface.
+local function box_on_load_cfg(box_cfg)
+    for k, v in pairs(log2box_keys) do
+        if box_cfg[v] ~= log_cfg[k] then
+            log_cfg[k] = box_cfg[v]
+        end
+    end
+end
+
 local compat_warning_said = false
 local compat_v16 = {
     logger_pid = function()
@@ -197,9 +235,28 @@ local log = {
     pid = log_pid,
     level = log_level,
     log_format = log_format,
+
+    -- Internal API to box module, not for users,
+    -- names can be changed.
+    box_api = {
+        set_log_level = function()
+            log_level(box.cfg.log_level)
+        end,
+        set_log_format = function()
+            log_format(box.cfg.log_format)
+        end,
+        on_load_cfg = box_on_load_cfg,
+        on_reload_cfg = box_on_load_cfg,
+        on_apply_default_cfg = box_on_apply_default_cfg,
+    },
 }
 
 setmetatable(log, {
+    __serialize = function(self)
+        local res = table.copy(self)
+        res.box_api = nil
+        return setmetatable(res, {})
+    end,
     __index = compat_v16;
 })
 
-- 
2.26.2