默认情况下,我的 Phoenix 应用程序通过 ~ 5 行日志输出记录有关每个 HTTP 请求的基本信息。只要我将日志级别设置为:debug
,我就可以查看每个请求的方法、路径、控制器和操作、参数、响应代码和持续时间:
2019-06-14 16:05:35.099 [info] GET /manage/projects/7qDjSk
2019-06-14 16:05:35.103 [debug] Processing with RTLWeb.Manage.ProjectController.show/2
Parameters: %{"project_uuid" => "7qDjSk"}
Pipelines: [:browser, :require_login]
2019-06-14 16:05:35.116 [info] Sent 200 in 17ms
这是一个很好的起点。但是我想自定义应用程序以将所有这些信息记录在一行上,这很有帮助,例如。在 Papertrail 等工具中筛选大量日志输出时。特别是我希望每个请求都以这样的格式显示:
[PUT /manage/projects/74/prompts/290] params=%{"project_uuid" => "74", "prompt" => %{"html" => "<div>Test question 3</div>"}, "prompt_uuid" => "290"} user=38 (Topher Hunt) status=302 redirected_to=/manage/projects/74 duration=423ms
在 Phoenix.Controller 文档中,我看到我可以为 Phoenix 控制器日志记录配置日志级别,或者完全禁用它,但我看不到自定义格式的方法。我该怎么做?
这不是自定义输出的问题,而是 1) 禁用默认的与请求相关的日志语句(通过分离相关的:telemetry
处理程序)然后 2) 添加一个新插件来记录我想要的格式。
这是我是如何做到的:
-
在
application.ex
中,在start/2
函数中,分离 Phoenix 默认为你附加的遥测处理程序。(调用:telemetry.list_handlers([])
以查看所有连接的侦听器。def start(_type, _args) do # ... # vvv ADD THESE vvv :ok = :telemetry.detach({Phoenix.Logger, [:phoenix, :socket_connected]}) :ok = :telemetry.detach({Phoenix.Logger, [:phoenix, :channel_joined]}) :ok = :telemetry.detach({Phoenix.Logger, [:phoenix, :router_dispatch, :start]}) # ... Supervisor.start_link(children, opts)
-
在
lib/my_app_web/endpoint.ex
中,注释掉Plug.Telemetry
插头。 -
在
lib/my_app_web/endpoint.ex
中,在 Plug.Session 之前添加此自定义插件:# One-line request logging. Must come before the session & router plugs. plug MyAppWeb.RequestLogger
-
最后,添加
lib/my_app_web/plugs/request_logger.ex
。(相应地调整详细信息;此实现假定登录用户结构存储在conn.assigns.current_user
中):# One-line full request logging inspired by Plug.Logger. # See https://github.com/elixir-plug/plug/blob/v1.8.0/lib/plug/logger.ex # Need to restart the server after updating this file. defmodule MyAppWeb.RequestLogger do require Logger @behaviour Plug def init(opts), do: opts def call(conn, _opts) do start_time = System.monotonic_time() Plug.Conn.register_before_send(conn, fn(conn) -> # We don't want passwords etc. being logged params = inspect(Phoenix.Logger.filter_values(conn.params)) # Log any important session data eg. logged-in user user = conn.assigns[:current_user] user_string = if user, do: "#{user.id} (#{user.name})", else: "(none)" # Note redirect, if any redirect = Plug.Conn.get_resp_header(conn, "location") redirect_string = if redirect != [], do: " redirected_to=#{redirect}", else: "" # Calculate time taken (in ms for consistency) stop_time = System.monotonic_time() time_us = System.convert_time_unit(stop_time - start_time, :native, :microsecond) time_ms = div(time_us, 100) / 10 Logger.log(:info, "■ method=#{conn.method} path=#{conn.request_path} params=#{params} "<> "user=#{user_string} status=#{conn.status}#{redirect_string} duration=#{time_ms}ms" ) conn end) end end
-
重新启动服务器,现在应该只看到每个请求一个日志行,格式如下:
2019-06-09 18:18:51.410 [info] ■ [PUT /manage/projects/7qDjSk/prompts/3tUrF9] params=%{"project_uuid" => "7qDjSk", "prompt" => %{"html" => "<div>Test question 3</div>"}, "prompt_uuid" => "3tUrF9"} user=1 (Topher Hunt) status=302 redirected_to=/manage/projects/7qDjSk duration=21ms
(注意:另一种更最佳实践的方法是:telemetry.attach
凤凰城已经发出的[:phoenix, :router_dispatch, :stop]
事件。这提供了我们需要的所有数据;有关更多详细信息,请参阅 Phoenix.Endpoint 文档。
有用的参考资料:
- https://hexdocs.pm/logger/1.8/Logger.html
- https://github.com/elixir-plug/plug/blob/v1.8.0/lib/plug/logger.ex
- https://www.verypossible.com/blog/thoughtful-logging-in-elixir-a-phoenix-story
- https://til.hashrocket.com/posts/o17nfvwzbo--list-all-telemetry-event-handlers
如果你想要 JSON 输出,还有这个: https://github.com/Nebo15/logger_json/tree/master/lib/logger_json