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
|
// +build ignore
package main
import (
"os"
"text/template"
)
func main() {
Run(handlersTemplate, nil, os.Args...)
}
var handlersTemplate = template.Must(template.New("").Parse(`package {{.Package}}
// go generate {{.Args}}
// GENERATED CODE FOLLOWS; DO NOT EDIT.
import (
"context"
{{range .Imports}}
{{ printf "%q" . -}}
{{end}}
)
{{.RequireType "E" -}}
{{.RequireType "ET" -}}
type (
// Handler is invoked upon the occurrence of some scheduler event that is generated
// by some other component in the Mesos ecosystem (e.g. master, agent, executor, etc.)
Handler interface {
HandleEvent(context.Context, {{.Type "E"}}) error
}
// HandlerFunc is a functional adaptation of the Handler interface
HandlerFunc func(context.Context, {{.Type "E"}}) error
// Handlers executes an event Handler according to the event's type
Handlers map[{{.Type "ET"}}]Handler
// HandlerFuncs executes an event HandlerFunc according to the event's type
HandlerFuncs map[{{.Type "ET"}}]HandlerFunc
)
// HandleEvent implements Handler for HandlerFunc
func (f HandlerFunc) HandleEvent(ctx context.Context, e {{.Type "E"}}) error { return f(ctx, e) }
type noopHandler int
func (noopHandler) HandleEvent(_ context.Context, _ {{.Type "E"}}) error { return nil }
// NoopHandler is a Handler that does nothing and always returns nil
const NoopHandler = noopHandler(0)
// HandleEvent implements Handler for Handlers
func (hs Handlers) HandleEvent(ctx context.Context, e {{.Type "E"}}) (err error) {
if h := hs[e.GetType()]; h != nil {
return h.HandleEvent(ctx, e)
}
return nil
}
// HandleEvent implements Handler for HandlerFuncs
func (hs HandlerFuncs) HandleEvent(ctx context.Context, e {{.Type "E"}}) (err error) {
if h := hs[e.GetType()]; h != nil {
return h.HandleEvent(ctx, e)
}
return nil
}
// Otherwise returns a HandlerFunc that attempts to process an event with the Handlers map; unmatched event types are
// processed by the given HandlerFunc. A nil HandlerFunc parameter is effecitvely a noop.
func (hs Handlers) Otherwise(f HandlerFunc) HandlerFunc {
if f == nil {
return hs.HandleEvent
}
return func(ctx context.Context, e {{.Type "E"}}) error {
if h := hs[e.GetType()]; h != nil {
return h.HandleEvent(ctx, e)
}
return f(ctx, e)
}
}
// Otherwise returns a HandlerFunc that attempts to process an event with the HandlerFuncs map; unmatched event types
// are processed by the given HandlerFunc. A nil HandlerFunc parameter is effecitvely a noop.
func (hs HandlerFuncs) Otherwise(f HandlerFunc) HandlerFunc {
if f == nil {
return hs.HandleEvent
}
return func(ctx context.Context, e {{.Type "E"}}) error {
if h := hs[e.GetType()]; h != nil {
return h.HandleEvent(ctx, e)
}
return f(ctx, e)
}
}
var (
_ = Handler(Handlers(nil))
_ = Handler(HandlerFunc(nil))
_ = Handler(HandlerFuncs(nil))
)
`))
|
