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
|
package wasm
import (
"context"
"errors"
"io"
"sync"
"github.com/tetratelabs/wazero"
"github.com/tetratelabs/wazero/sys"
)
type Args struct {
// Standard FDs.
Stdin io.Reader
Stdout io.Writer
Stderr io.Writer
// CLI args.
Args []string
// Optional further module configuration function.
// (e.g. to mount filesystem dir, set env vars, etc).
Config func(wazero.ModuleConfig) wazero.ModuleConfig
}
type Instantiator struct {
// Module ...
Module string
// Runtime ...
Runtime func(context.Context) wazero.Runtime
// Config ...
Config func() wazero.ModuleConfig
// Source ...
Source []byte
}
func (inst *Instantiator) New(ctx context.Context) (*Instance, error) {
switch {
case inst.Module == "":
panic("missing module name")
case inst.Runtime == nil:
panic("missing runtime instantiator")
case inst.Config == nil:
panic("missing module configuration")
case len(inst.Source) == 0:
panic("missing module source")
}
// Create new host runtime.
rt := inst.Runtime(ctx)
// Compile guest module from WebAssembly source.
mod, err := rt.CompileModule(ctx, inst.Source)
if err != nil {
return nil, err
}
return &Instance{
inst: inst,
wzrt: rt,
cmod: mod,
}, nil
}
type InstancePool struct {
Instantiator
pool []*Instance
lock sync.Mutex
}
func (p *InstancePool) Get(ctx context.Context) (*Instance, error) {
for {
// Check for cached.
inst := p.Cached()
if inst == nil {
break
}
// Check if closed.
if inst.IsClosed() {
continue
}
return inst, nil
}
// Must create new instance.
return p.Instantiator.New(ctx)
}
func (p *InstancePool) Put(inst *Instance) {
if inst.inst != &p.Instantiator {
panic("instance and pool instantiators do not match")
}
p.lock.Lock()
p.pool = append(p.pool, inst)
p.lock.Unlock()
}
func (p *InstancePool) Cached() *Instance {
var inst *Instance
p.lock.Lock()
if len(p.pool) > 0 {
inst = p.pool[len(p.pool)-1]
p.pool = p.pool[:len(p.pool)-1]
}
p.lock.Unlock()
return inst
}
// Instance ...
//
// NOTE: Instance is NOT concurrency
// safe. One at a time please!!
type Instance struct {
inst *Instantiator
wzrt wazero.Runtime
cmod wazero.CompiledModule
}
func (inst *Instance) Run(ctx context.Context, args Args) (uint32, error) {
if inst.inst == nil {
panic("not initialized")
}
// Check instance open.
if inst.IsClosed() {
return 0, errors.New("instance closed")
}
// Prefix binary name as argv0 to args.
cargs := make([]string, len(args.Args)+1)
copy(cargs[1:], args.Args)
cargs[0] = inst.inst.Module
// Create base module config.
modcfg := inst.inst.Config()
modcfg = modcfg.WithName(inst.inst.Module)
modcfg = modcfg.WithArgs(cargs...)
modcfg = modcfg.WithStdin(args.Stdin)
modcfg = modcfg.WithStdout(args.Stdout)
modcfg = modcfg.WithStderr(args.Stderr)
if args.Config != nil {
// Pass through config fn.
modcfg = args.Config(modcfg)
}
// Instantiate the module from precompiled wasm module data.
mod, err := inst.wzrt.InstantiateModule(ctx, inst.cmod, modcfg)
if mod != nil {
// Close module.
mod.Close(ctx)
}
// Check for a returned exit code error.
if err, ok := err.(*sys.ExitError); ok {
return err.ExitCode(), nil
}
return 0, err
}
func (inst *Instance) IsClosed() bool {
return (inst.wzrt == nil || inst.cmod == nil)
}
func (inst *Instance) Close(ctx context.Context) error {
if inst.IsClosed() {
return nil
}
err1 := inst.cmod.Close(ctx)
err2 := inst.wzrt.Close(ctx)
return errors.Join(err1, err2)
}
|
