1supervisor_bridge(3) Erlang Module Definition supervisor_bridge(3)
2
6 supervisor_bridge - Generic supervisor bridge behavior.
7
9 This behavior module provides a supervisor bridge, a process that con‐
10 nects a subsystem not designed according to the OTP design principles
11 to a supervision tree. The supervisor bridge sits between a supervisor
12 and the subsystem. It behaves like a real supervisor to its own super‐
13 visor, but has a different interface than a real supervisor to the sub‐
14 system. For more information, see Supervisor Behaviour in OTP Design
15 Principles.
16 A supervisor bridge assumes the functions for starting and stopping the
18 subsystem to be located in a callback module exporting a predefined set
19 of functions.
20 The sys(3) module can be used for debugging a supervisor bridge.
22 Unless otherwise stated, all functions in this module fail if the spec‐
24 ified supervisor bridge does not exist or if bad arguments are speci‐
25 fied.
26
28 start_link(Module, Args) -> Result
29 start_link(SupBridgeName, Module, Args) -> Result
31 Types:
33 SupBridgeName = {local, Name} | {global, Name}
35 Name = atom()
36 Module = module()
37 Args = term()
38 Result = {ok, Pid} | ignore | {error, Error}
39 Error = {already_started, Pid} | term()
40 Pid = pid()
41 Creates a supervisor bridge process, linked to the calling
43 process, which calls Module:init/1 to start the subsystem. To
44 ensure a synchronized startup procedure, this function does not
45 return until Module:init/1 has returned.
46 * If SupBridgeName={local,Name}, the supervisor bridge is reg‐
48 istered locally as Name using register/2.
49 * If SupBridgeName={global,Name}, the supervisor bridge is
51 registered globally as Name using global:register_name/2.
52 * If SupBridgeName={via,Module,Name}, the supervisor bridge is
54 registered as Name using a registry represented by Module.
55 The Module callback is to export functions register_name/2,
56 unregister_name/1, and send/2, which are to behave like the
57 corresponding functions in global. Thus, {via,global,Global‐
58 Name} is a valid reference.
59 If no name is provided, the supervisor bridge is not registered.
61 Module is the name of the callback module.
63 Args is an arbitrary term that is passed as the argument to Mod‐
65 ule:init/1.
66 * If the supervisor bridge and the subsystem are successfully
68 started, the function returns {ok,Pid}, where Pid is is the
69 pid of the supervisor bridge.
70 * If there already exists a process with the specified Sup‐
72 BridgeName, the function returns {error,{al‐
73 ready_started,Pid}}, where Pid is the pid of that process.
74 * If Module:init/1 returns ignore, this function returns ig‐
76 nore as well and the supervisor bridge terminates with rea‐
77 son normal.
78 * If Module:init/1 fails or returns an error tuple or an in‐
80 correct value, this function returns {error,Errorr}, where
81 Error is a term with information about the error, and the
82 supervisor bridge terminates with reason Error.
83
85 The following functions must be exported from a supervisor_bridge call‐
86 back module.
87
89 Module:init(Args) -> Result
90 Types:
92 Args = term()
94 Result = {ok,Pid,State} | ignore | {error,Error}
95 Pid = pid()
96 State = term()
97 Error = term()
98 Whenever a supervisor bridge is started using start_link/2,3,
100 this function is called by the new process to start the subsys‐
101 tem and initialize.
102 Args is the Args argument provided to the start function.
104 The function is to return {ok,Pid,State}, where Pid is the pid
106 of the main process in the subsystem and State is any term.
107 If later Pid terminates with a reason Reason, the supervisor
109 bridge terminates with reason Reason as well. If later the su‐
110 pervisor bridge is stopped by its supervisor with reason Reason,
111 it calls Module:terminate(Reason,State) to terminate.
112 If the initialization fails, the function is to return {er‐
114 ror,Error}, where Error is any term, or ignore.
115 Module:terminate(Reason, State)
117 Types:
119 Reason = shutdown | term()
121 State = term()
122 This function is called by the supervisor bridge when it is
124 about to terminate. It is to be the opposite of Module:init/1
125 and stop the subsystem and do any necessary cleaning up. The re‐
126 turn value is ignored.
127 Reason is shutdown if the supervisor bridge is terminated by its
129 supervisor. If the supervisor bridge terminates because a a
130 linked process (apart from the main process of the subsystem)
131 has terminated with reason Term, then Reason becomes Term.
132 State is taken from the return value of Module:init/1.
134
136 supervisor(3), sys(3)
137Ericsson AB stdlib 3.14.2.1 supervisor_bridge(3)