[Tarantool-patches] [PATCH v2 09/10] lua/log: allow to configure logging without a box

[Cyrill Gorcunov]

Now a user can configure logging without running `box.cfg{}`.
The syntax is the same as in `box.cfg{}` call.

Fixes #689

Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
---
 src/box/lua/load_cfg.lua |  7 +++++
 src/lua/log.lua          | 68 +++++++++++++++++++++++++++++++++++++---
 2 files changed, 70 insertions(+), 5 deletions(-)

diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
index 9aef12840..232a1695a 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -478,6 +478,12 @@ local function apply_default_modules_cfg(cfg)
     end
 end
 
+local function update_modules_cfg(cfg)
+    --
+    -- logging
+    log.box_api.cfg_update(cfg)
+end
+
 -- Return true if two configurations are equivalent.
 local function compare_cfg(cfg1, cfg2)
     if type(cfg1) ~= type(cfg2) then
@@ -597,6 +603,7 @@ local function load_cfg(cfg)
             end
         end
     end
+    update_modules_cfg(cfg)
     if not box.cfg.read_only and not box.cfg.replication then
         box.schema.upgrade{auto = true}
     end
diff --git a/src/lua/log.lua b/src/lua/log.lua
index 25c919412..c82390897 100644
--- a/src/lua/log.lua
+++ b/src/lua/log.lua
@@ -97,6 +97,14 @@ local fmt_str2num = {
     ["json"]            = ffi.C.SF_JSON,
 }
 
+local function fmt_list()
+    local keyset = {}
+    for k,_ in pairs(fmt_str2num) do
+        keyset[#keyset+1] = k
+    end
+    return table.concat(keyset,',')
+end
+
 --
 -- Default options. The keys are part of
 -- user API, so change with caution.
@@ -168,12 +176,8 @@ end
 
 local function log_format(name)
     if not fmt_str2num[name] then
-        local keyset = {}
-        for k,_ in pairs(fmt_str2num) do
-            keyset[#keyset+1] = k
-        end
         local m = "log_format: expected %s"
-        error(m:format(table.concat(keyset,',')))
+        error(m:format(fmt_list()))
     end
 
     if fmt_str2num[name] == ffi.C.SF_JSON then
@@ -194,6 +198,55 @@ local function log_pid()
     return tonumber(ffi.C.log_pid)
 end
 
+--
+-- Initialize logger early (if not yet set up
+-- via box.cfg interface.
+--
+local function log_init(args)
+    if ffi.C.say_logger_initialized() == true then
+        error("log: the logger is already initialized")
+    end
+
+    args = args or {}
+
+    if args.log_format ~= nil then
+        if fmt_str2num[args.log_format] == nil then
+            local m = "log: 'log_format' must be %s"
+            error(m:format(fmt_list()))
+        end
+    else
+        args.log_format = log_cfg.log_format
+    end
+
+    args.log_level = args.log_level or log_cfg.log_level
+
+    args.log_nonblock = args.log_nonblock or (log_cfg.log_nonblock or false)
+
+    --
+    -- We never allow confgure the logger in background
+    -- mode since we don't know how the box will be configured
+    -- later.
+    ffi.C.say_logger_init(args.log, args.log_level,
+                          args.log_nonblock, args.log_format, 0)
+
+    --
+    -- Update log_cfg vars to show them in module
+    -- configuration output.
+    rawset(log_cfg, 'log', args.log)
+    rawset(log_cfg, 'log_level', args.log_level)
+    rawset(log_cfg, 'log_nonblock', args.log_nonblock)
+    rawset(log_cfg, 'log_format', args.log_format)
+end
+
+--
+-- Reflect the changes made by box.cfg interface
+local function box_cfg_update(box_cfg)
+    rawset(log_cfg, 'log', box_cfg.log)
+    rawset(log_cfg, 'log_level', box_cfg.log_level)
+    rawset(log_cfg, 'log_nonblock', box_cfg.log_nonblock)
+    rawset(log_cfg, 'log_format', box_cfg.log_format)
+end
+
 local compat_warning_said = false
 local compat_v16 = {
     logger_pid = function()
@@ -215,6 +268,7 @@ local log ={
     pid = log_pid,
     level = log_level,
     log_format = log_format,
+    cfg = log_init,
     --
     -- Internal API to box module, not for users,
     -- names can be changed.
@@ -226,6 +280,7 @@ local log ={
         set_log_format = function()
             log_format(box.cfg.log_format)
         end,
+        cfg_update = box_cfg_update,
     },
 }
 
@@ -233,6 +288,9 @@ setmetatable(log, {
     __serialize = function(self)
         local res = table.copy(self)
         res.box_api = nil
+        if ffi.C.say_logger_initialized() == true then
+            res.cfg = log_cfg
+        end
         return setmetatable(res, {})
     end,
     __index = compat_v16;
-- 
2.26.2