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
73 {error,{already_started,Pid}}, where Pid is the pid of that
74 process.
75 * If Module:init/1 returns ignore, this function returns
77 ignore as well and the supervisor bridge terminates with
78 reason normal.
79 * If Module:init/1 fails or returns an error tuple or an
81 incorrect value, this function returns {error,Errorr}, where
82 Error is a term with information about the error, and the
83 supervisor bridge terminates with reason Error.
84
86 The following functions must be exported from a supervisor_bridge call‐
87 back module.
88
90 Module:init(Args) -> Result
91 Types:
93 Args = term()
95 Result = {ok,Pid,State} | ignore | {error,Error}
96 Pid = pid()
97 State = term()
98 Error = term()
99 Whenever a supervisor bridge is started using start_link/2,3,
101 this function is called by the new process to start the subsys‐
102 tem and initialize.
103 Args is the Args argument provided to the start function.
105 The function is to return {ok,Pid,State}, where Pid is the pid
107 of the main process in the subsystem and State is any term.
108 If later Pid terminates with a reason Reason, the supervisor
110 bridge terminates with reason Reason as well. If later the
111 supervisor bridge is stopped by its supervisor with reason Rea‐
112 son, it calls Module:terminate(Reason,State) to terminate.
113 If the initialization fails, the function is to return
115 {error,Error}, where Error is any term, or ignore.
116 Module:terminate(Reason, State)
118 Types:
120 Reason = shutdown | term()
122 State = term()
123 This function is called by the supervisor bridge when it is
125 about to terminate. It is to be the opposite of Module:init/1
126 and stop the subsystem and do any necessary cleaning up. The
127 return value is ignored.
128 Reason is shutdown if the supervisor bridge is terminated by its
130 supervisor. If the supervisor bridge terminates because a a
131 linked process (apart from the main process of the subsystem)
132 has terminated with reason Term, then Reason becomes Term.
133 State is taken from the return value of Module:init/1.
135
137 supervisor(3), sys(3)
138Ericsson AB stdlib 3.4.5.1 supervisor_bridge(3)