/
spec.ex
267 lines (201 loc) · 8.95 KB
/
spec.ex
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
defmodule Supervisor.Spec do
@moduledoc """
NOTE: The functions in this module are deprecated and they do not
work with the module-based child specs introduced in Elixir v1.5.
Please see the `Supervisor` documentation instead.
Convenience functions for defining supervisor specifications.
## Example
By using the functions in this module one can specify the children
to be used under a supervisor, started with `Supervisor.start_link/2`:
import Supervisor.Spec
children = [
worker(MyWorker, [arg1, arg2, arg3]),
supervisor(MySupervisor, [arg1])
]
Supervisor.start_link(children, strategy: :one_for_one)
Sometimes, it may be handy to define supervisors backed
by a module:
defmodule MySupervisor do
use Supervisor
def start_link(arg) do
Supervisor.start_link(__MODULE__, arg)
end
def init(arg) do
children = [
worker(MyWorker, [arg], restart: :temporary)
]
supervise(children, strategy: :simple_one_for_one)
end
end
Notice in this case we don't have to explicitly import
`Supervisor.Spec` as `use Supervisor` automatically does so.
Defining a module-based supervisor can be useful, for example,
to perform initialization tasks in the `c:init/1` callback.
## Supervisor and worker options
In the example above, we defined specs for workers and supervisors.
These specs (both for workers as well as supervisors) accept the
following options:
* `:id` - a name used to identify the child specification
internally by the supervisor; defaults to the given module
name for the child worker/supervisor
* `:function` - the function to invoke on the child to start it
* `:restart` - an atom that defines when a terminated child process should
be restarted (see the "Restart values" section below)
* `:shutdown` - an atom that defines how a child process should be
terminated (see the "Shutdown values" section below)
* `:modules` - it should be a list with one element `[module]`,
where module is the name of the callback module only if the
child process is a `Supervisor` or `GenServer`; if the child
process is a `GenEvent`, `:modules` should be `:dynamic`
### Restart values (:restart)
The following restart values are supported in the `:restart` option:
* `:permanent` - the child process is always restarted
* `:temporary` - the child process is never restarted (not even
when the supervisor's strategy is `:rest_for_one` or `:one_for_all`)
* `:transient` - the child process is restarted only if it
terminates abnormally, i.e., with an exit reason other than
`:normal`, `:shutdown` or `{:shutdown, term}`
Notice that supervisor that reached maximum restart intensity will exit with `:shutdown` reason.
In this case the supervisor will only be restarted if its child specification was defined with
the `:restart` option is set to `:permanent` (the default).
### Shutdown values (:shutdown)
The following shutdown values are supported in the `:shutdown` option:
* `:brutal_kill` - the child process is unconditionally terminated
using `Process.exit(child, :kill)`
* `:infinity` - if the child process is a supervisor, this is a mechanism
to give the subtree enough time to shutdown; it can also be used with
workers with care
* any integer - the value of `:shutdown` can also be any integer meaning
that the supervisor tells the child process to terminate by calling
`Process.exit(child, :shutdown)` and then waits for an exit signal back.
If no exit signal is received within the specified time (the value of this
option, in milliseconds), the child process is unconditionally terminated
using `Process.exit(child, :kill)`
"""
# TODO: Deprecate all functions in this module on Elixir v1.8.
# Also deprecate entry in Supervisor.Default.
@typedoc "Supported strategies"
@type strategy :: :simple_one_for_one | :one_for_one | :one_for_all | :rest_for_one
@typedoc "Supported restart values"
@type restart :: :permanent | :transient | :temporary
@typedoc "Supported shutdown values"
@type shutdown :: timeout | :brutal_kill
@typedoc "Supported worker values"
@type worker :: :worker | :supervisor
@typedoc "Supported module values"
@type modules :: :dynamic | [module]
@typedoc "Supported id values"
@type child_id :: term
@typedoc "The supervisor specification"
@type spec :: {child_id,
start_fun :: {module, atom, [term]},
restart,
shutdown,
worker,
modules}
@doc """
Receives a list of children (workers or supervisors) to
supervise and a set of options.
Returns a tuple containing the supervisor specification. This tuple can be
used as the return value of the `c:init/1` callback when implementing a
module-based supervisor.
## Examples
supervise(children, strategy: :one_for_one)
## Options
* `:strategy` - the restart strategy option. It can be either
`:one_for_one`, `:rest_for_one`, `:one_for_all`, or
`:simple_one_for_one`. You can learn more about strategies
in the `Supervisor` module docs.
* `:max_restarts` - the maximum amount of restarts allowed in
a time frame. Defaults to `3`.
* `:max_seconds` - the time frame in which `:max_restarts` applies.
Defaults to `5`.
The `:strategy` option is required and by default a maximum of 3 restarts is
allowed within 5 seconds. Check the `Supervisor` module for a detailed
description of the available strategies.
"""
@spec supervise([spec], strategy: strategy,
max_restarts: non_neg_integer,
max_seconds: pos_integer) :: {:ok, tuple}
def supervise(children, options) do
unless strategy = options[:strategy] do
raise ArgumentError, "expected :strategy option to be given"
end
maxR = Keyword.get(options, :max_restarts, 3)
maxS = Keyword.get(options, :max_seconds, 5)
assert_unique_ids(Enum.map(children, &get_id/1))
{:ok, {{strategy, maxR, maxS}, children}}
end
defp get_id({id, _, _, _, _, _}) do
id
end
defp get_id(other) do
raise ArgumentError,
"invalid tuple specification given to supervise/2. If you are trying to use " <>
"the map child specification that is part of the Elixir v1.5, use Supervisor.init/2 " <>
"instead of Supervisor.Spec.supervise/2. See the Supervisor module for more information. " <>
"Got: #{inspect other}"
end
defp assert_unique_ids([id | rest]) do
if id in rest do
raise ArgumentError,
"duplicated id #{inspect id} found in the supervisor specification, " <>
"please explicitly pass the :id option when defining this worker/supervisor"
else
assert_unique_ids(rest)
end
end
defp assert_unique_ids([]) do
:ok
end
@doc """
Defines the given `module` as a worker which will be started
with the given arguments.
worker(ExUnit.Runner, [], restart: :permanent)
By default, the function `start_link` is invoked on the given
module. Overall, the default values for the options are:
[id: module,
function: :start_link,
restart: :permanent,
shutdown: 5000,
modules: [module]]
Check the documentation for the `Supervisor.Spec` module for more
information on the options.
"""
@spec worker(module, [term], [restart: restart, shutdown: shutdown,
id: term, function: atom, modules: modules]) :: spec
def worker(module, args, options \\ []) do
child(:worker, module, args, options)
end
@doc """
Defines the given `module` as a supervisor which will be started
with the given arguments.
supervisor(ExUnit.Runner, [], restart: :permanent)
By default, the function `start_link` is invoked on the given
module. Overall, the default values for the options are:
[id: module,
function: :start_link,
restart: :permanent,
shutdown: :infinity,
modules: [module]]
Check the documentation for the `Supervisor.Spec` module for more
information on the options.
"""
@spec supervisor(module, [term], [restart: restart, shutdown: shutdown,
id: term, function: atom, modules: modules]) :: spec
def supervisor(module, args, options \\ []) do
options = Keyword.put_new(options, :shutdown, :infinity)
child(:supervisor, module, args, options)
end
defp child(type, module, args, options) do
id = Keyword.get(options, :id, module)
modules = Keyword.get(options, :modules, modules(module))
function = Keyword.get(options, :function, :start_link)
restart = Keyword.get(options, :restart, :permanent)
shutdown = Keyword.get(options, :shutdown, 5000)
{id, {module, function, args},
restart, shutdown, type, modules}
end
defp modules(GenEvent), do: :dynamic
defp modules(module), do: [module]
end