监督者桥接与混合进程层次结构
使用 supervisor_bridge 将非 OTP 进程和外部子系统集成到监督树中，同时保持容错能力。
监督者桥接与混合进程层次结构 是 CoddyKit 上的免费 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课时。 这是第 4 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
Why a Supervisor Bridge?
Not every process you depend on is a clean OTP gen_server. Sometimes you must supervise a plain Erlang process, a port, or a third-party subsystem. The supervisor_bridge behaviour lets such a process appear as a normal child in a supervision tree.
The Problem It Solves
A standard supervisor only knows how to start, stop and restart OTP-compliant children. A raw process started with spawn_link does not respond to OTP shutdown protocols. The bridge translates between the two worlds.
Behaviour Callbacks
A supervisor_bridge module implements two callbacks:
init/1starts the real subsystem and returns its pidterminate/2cleanly shuts the subsystem down
Skeleton Module
The bridge is started like a supervisor but behaves like a worker to its parent.
-module(legacy_bridge).
-behaviour(supervisor_bridge).
-export([start_link/0, init/1, terminate/2]).
start_link() ->
supervisor_bridge:start_link({local, ?MODULE}, ?MODULE, []).Implementing init/1
init/1 must start and link the external process, then return {ok, Pid, State}. If start fails, return {error, Reason}.
init([]) ->
case legacy_server:start() of
{ok, Pid} -> {ok, Pid, Pid};
Error -> Error
end.Implementing terminate/2
When the bridge is asked to shut down, it calls terminate/2 so you can stop the subsystem gracefully.
terminate(_Reason, Pid) ->
legacy_server:stop(Pid),
ok.Placing the Bridge in a Tree
To its parent supervisor, the bridge is just another child spec with type => worker.
ChildSpec = #{id => legacy,
start => {legacy_bridge, start_link, []},
restart => permanent,
type => worker}.Failure Propagation
Because the bridge links to the external process, a crash there exits the bridge, which the parent supervisor sees as a normal worker crash and restarts according to its strategy.
Mixed Hierarchies
A real system mixes gen_server workers, sub-supervisors, and bridges. The bridge lets legacy or foreign code participate without weakening the OTP guarantees of the rest of the tree.
When NOT to Use a Bridge
If you can wrap the subsystem in a proper gen_server, prefer that — it gives you full OTP introspection. Reserve the bridge for code you cannot rewrite or that has its own process lifecycle.
Debugging Bridged Subsystems
Because the inner process is not OTP, tools like sys:get_state/1 will not reach it. Add logging inside the subsystem and rely on the bridge state to track the inner pid.
Quick Check
Test your understanding of supervisor bridges.
Recap
You learned to integrate foreign processes into supervision trees:
supervisor_bridgewraps non-OTP subsystemsinit/1starts and links the subsystem;terminate/2stops it- It appears as a worker child to its parent supervisor
- Crashes propagate so normal restart strategies apply
- Prefer a real gen_server when you control the code
常见问题解答
「监督者桥接与混合进程层次结构」课时是免费的吗？
是的 — 「监督者桥接与混合进程层次结构」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课程的其余内容，请升级到 CoddyKit PRO。 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课程共包含 4 节课。
「监督者桥接与混合进程层次结构」这节课中我会学到什么？
使用 supervisor_bridge 将非 OTP 进程和外部子系统集成到监督树中，同时保持容错能力。 你通过在浏览器中直接运行的动手代码来练习 Erlang OTP: Distributed & Fault-Tolerant Systems Programming，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 4 节课，共 4 节。
「监督者桥接与混合进程层次结构」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课中编写并运行代码吗？
能。每节 Erlang OTP: Distributed & Fault-Tolerant Systems Programming 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。