refactor some lua code

rootfs/etc/nginx/lua/util/split.lua

@@ -0,0 +1,70 @@
+local _M = {}
+
+-- splits strings into host and port
+local function parse_addr(addr)
+  local _, _, host, port = addr:find("([^:]+):([^:]+)")
+  if host and port then
+    return {host=host, port=port}
+  else
+    return nil, "error in parsing upstream address!"
+  end
+end
+
+function _M.get_first_value(var)
+  local t = _M.split_upstream_var(var) or {}
+  if #t == 0 then return nil end
+  return t[1]
+end
+
+function _M.split_pair(pair, seperator)
+  local i = pair:find(seperator)
+  if i == nil then
+    return pair, nil
+  else
+    local name = pair:sub(1, i - 1)
+    local value = pair:sub(i + 1, -1)
+    return name, value
+  end
+end
+
+-- http://nginx.org/en/docs/http/ngx_http_upstream_module.html#example
+-- CAVEAT: nginx is giving out : instead of , so the docs are wrong
+-- 127.0.0.1:26157 : 127.0.0.1:26157 , ngx.var.upstream_addr
+-- 200 : 200 , ngx.var.upstream_status
+-- 0.00 : 0.00, ngx.var.upstream_response_time
+function _M.split_upstream_var(var)
+  if not var then
+    return nil, nil
+  end
+  local t = {}
+  for v in var:gmatch("[^%s|,]+") do
+    if v ~= ":" then
+      t[#t+1] = v
+    end
+  end
+  return t
+end
+
+-- Splits an NGINX $upstream_addr and returns an array of tables with a `host` and `port` key-value pair.
+function _M.split_upstream_addr(addrs_str)
+  if not addrs_str then
+    return nil, nil
+  end
+
+  local addrs = _M.split_upstream_var(addrs_str)
+  local host_and_ports = {}
+
+  for _, v in ipairs(addrs) do
+    local a, err = parse_addr(v)
+    if err then
+      return nil, err
+    end
+    host_and_ports[#host_and_ports+1] = a
+  end
+  if #host_and_ports == 0 then
+    return nil, "no upstream addresses to parse!"
+  end
+  return host_and_ports
+end
+
+return _M