[Feature] Add universal function to parse redis servers for plugins

src/lua/global_functions.lua

@@ -0,0 +1,56 @@
+
+-- This function parses redis server definition using either
+-- specific server string for this module or global
+-- redis section
+function rspamd_parse_redis_server(module_name)
+
+  local default_port = 6379
+  local logger = require "rspamd_logger"
+
+  local function try_load_redis_servers(options)
+    local key = options['servers']
+
+    if not key then key = options['server'] end
+
+    if key then
+      local upstreams = upstream_list.create(rspamd_config, key, default_port)
+
+      if upstreams then
+        return upstreams
+      end
+    end
+
+    return nil
+  end
+
+  local opts = rspamd_config:get_all_opt(module_name)
+  local ret
+
+  if opts then
+    ret = try_load_redis_servers(opts)
+  end
+
+  if ret then
+    return ret
+  end
+
+  opts = rspamd_config:get_all_opt('redis')
+
+  if opts then
+    if opts[module_name] then
+      ret = try_load_redis_servers(opts[module_name])
+      if ret then
+        return ret
+      end
+    else
+      ret = try_load_redis_servers(opts)
+
+      if ret then
+        logger.infox(rspamd_config, "using default redis server for module %s",
+          module_name)
+      end
+    end
+  end
+
+  return ret
+end