config: create dirs relative to process.work_dir

The current working directory of a tarantool process is changed during
startup to `process.work_dir`.

The mkdir applier works before and after this point, so it should take
into account both situations.

Before first box.cfg() call (in the box_cfg applier) it should prepend
directories with `process.work_dir`. However, it shouldn't do that after
the current wordking directory change.

Part of #8862

NO_DOC=It is bugfix.

changelogs/unreleased/config-create-parent-directories.md

@@ -4,3 +4,5 @@
   file (gh-8862).
 * Create parent directories for `console.socket` and `log.file` (gh-8862).
 * Create the `process.work_dir` directory (gh-8862).
+* Consider all the paths as relative to `process.work_dir` when creating
+  necessary directories (gh-8862).

src/box/lua/config/applier/mkdir.lua

@@ -2,7 +2,21 @@ local fio = require('fio')
 local log = require('internal.config.utils.log')
 
 -- Create a directory if it doesn't exist.
-local function safe_mkdir(prefix, dir)
+local function safe_mkdir(prefix, dir, work_dir)
+    -- All the directories are interpreted as relative to
+    -- `process.work_dir`. The first box.cfg() call sets a
+    -- current working directory to this path.
+    --
+    -- However, we should prepend paths manually before the first
+    -- box.cfg() call.
+    --
+    -- The absolute path is checked explicitly due to gh-8816.
+    local needs_prepending = type(box.cfg) == 'function' and
+        work_dir ~= nil and not dir:startswith('/')
+    if needs_prepending then
+        dir = fio.pathjoin(work_dir, dir)
+    end
+
     local stat = fio.stat(dir)
 
     if stat == nil then
@@ -24,16 +38,13 @@ end
 
 local function apply(config)
     local configdata = config._configdata
+    local work_dir = configdata:get('process.work_dir', {use_default = true})
 
     -- Create process.work_dir directory if box.cfg() is not
     -- called yet.
-    if type(box.cfg) == 'function' then
-        local work_dir = configdata:get('process.work_dir',
-            {use_default = true})
-        if work_dir ~= nil then
-            local prefix = ('mkdir.apply[%s]'):format('process.work_dir')
-            safe_mkdir(prefix, work_dir)
-        end
+    if type(box.cfg) == 'function' and work_dir ~= nil then
+        local prefix = ('mkdir.apply[%s]'):format('process.work_dir')
+        safe_mkdir(prefix, work_dir)
     end
 
     configdata:filter(function(w)
@@ -43,7 +54,7 @@ local function apply(config)
             return
         end
         local prefix = ('mkdir.apply[%s]'):format(table.concat(w.path, '.'))
-        safe_mkdir(prefix, w.data)
+        safe_mkdir(prefix, w.data, work_dir)
     end)
 
     configdata:filter(function(w)
@@ -53,19 +64,19 @@ local function apply(config)
             return
         end
         local prefix = ('mkdir.apply[%s]'):format(table.concat(w.path, '.'))
-        safe_mkdir(prefix, fio.dirname(w.data))
+        safe_mkdir(prefix, fio.dirname(w.data), work_dir)
     end)
 
     local console = configdata:get('console', {use_default = true})
     if console.enabled then
         local prefix = ('mkdir.apply[%s]'):format('console.socket')
-        safe_mkdir(prefix, fio.dirname(console.socket))
+        safe_mkdir(prefix, fio.dirname(console.socket), work_dir)
     end
 
     local log = configdata:get('log', {use_default = true})
     if log.to == 'file' then
         local prefix = ('mkdir.apply[%s]'):format('log.file')
-        safe_mkdir(prefix, fio.dirname(log.file))
+        safe_mkdir(prefix, fio.dirname(log.file), work_dir)
     end
 end
 

test/config-luatest/mkdir_test.lua

@@ -71,3 +71,60 @@ g.test_work_dir = function(g)
         verify_2 = verify,
     })
 end
+
+-- Verify the logic of directories calculation relative to
+-- process.work_dir at startup and reload.
+--
+-- See the comments in the verify() function in the test
+-- for details what exactly is verified.
+g.test_dirs_are_relative_to_work_dir = function(g)
+    local dir = treegen.prepare_directory(g, {}, {})
+
+    local verify = loadstring(([[
+        local fio = require('fio')
+
+        local dirs = {'d', 'e', 'f', 'g', 'h', 'i'}
+
+        -- The requested directories are NOT created in the
+        -- startup dir.
+        local startup_dir = '%s'
+        for _, dir in ipairs(dirs) do
+            assert(not fio.path.exists(fio.pathjoin(startup_dir, dir)))
+        end
+
+        -- The requested directories are created in the work_dir.
+        local work_dir = fio.pathjoin(startup_dir, 'a/b/c')
+        for _, dir in ipairs(dirs) do
+            assert(fio.path.is_dir(dir))
+        end
+
+        -- The process.work_dir value should be used as a prefix
+        -- for requested directories only at startup. After this,
+        -- on reload, it would be harmful, because the process
+        -- has already changed the current working directory to
+        -- the work_dir.
+        assert(not fio.path.exists(fio.pathjoin(work_dir, 'a')))
+    ]]):format(dir))
+
+    helpers.reload_success_case(g, {
+        dir = dir,
+        options = {
+            ['process.work_dir'] = 'a/b/c',
+            ['process.pid_file'] = 'd/{{ instance_name }}.pid',
+            ['vinyl.dir'] = 'e',
+            ['wal.dir'] = 'f',
+            ['snapshot.dir'] = 'g',
+            ['console.socket'] = 'h/{{ instance_name }}.control',
+            ['log.to'] = 'file',
+            ['log.file'] = 'i/{{ instance_name }}.log',
+
+            -- Set the binary protocol socket as an absolute path
+            -- to don't confuse the testing helpers and allows
+            -- them to connect to the instance and execute
+            -- necessary commands (such as `config:reload()`).
+            ['iproto.listen'] = fio.pathjoin(dir, '{{ instance_name }}.iproto'),
+        },
+        verify = verify,
+        verify_2 = verify,
+    })
+end