Consistent Early-Exit Style

When updating/adding code, prioritize readability and predictable control-flow:

• Use early exits (return/goto/continue) for error/invalid states to avoid deep nesting/extra indentation.
• Keep error-handling visually tight (no distracting blank lines between the call and the error check).
• For error logs, follow formatting rules:
  • Avoid Lua string concatenation inside ngx_log/ngx.log; pass multiple arguments instead.
  • Use the required capitalization for error messages (e.g., don’t capitalize the message text).
• Prefer clearer positive conditions over negated/complex expressions, and simplify large if/else chains where possible.

Example pattern (body parsing + early exit + logging):

local body, err = kong.request.get_body()
if err then
  ngx_log(ngx.ERR, "cannot process request body: ", tostring(err))
  return
end

local identifier = body  -- proceed normally

Example logging without concatenation:

ngx_log(ngx.ERR, "request failed (", req_url, "): ", err)