|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "fmt" |
| 5 | + "io" |
| 6 | + "log" |
| 7 | + "math/rand" |
| 8 | + "os" |
| 9 | + "sync" |
| 10 | + |
| 11 | + "github.com/dop251/goja" |
| 12 | + "github.com/envoyproxy/dynamic-modules-examples/go/gosdk" |
| 13 | +) |
| 14 | + |
| 15 | +const ( |
| 16 | + javaScriptExportedSymbolOnConfig = "OnConfigure" |
| 17 | + javaScriptExportedSymbolOnRequestHeaders = "OnRequestHeaders" |
| 18 | + javaScriptExportedSymbolOnResponseHeaders = "OnResponseHeaders" |
| 19 | + |
| 20 | + functionDeclTemplate = `globalThis.%[1]s = %[1]s` |
| 21 | + numberOfVMPool = 24 |
| 22 | +) |
| 23 | + |
| 24 | +type ( |
| 25 | + // javaScriptFilterConfig implements [gosdk.HttpFilterConfig]. |
| 26 | + javaScriptFilterConfig struct { |
| 27 | + vms [numberOfVMPool]*javaScriptVM |
| 28 | + } |
| 29 | + // javaScriptFilter implements [gosdk.HttpFilter]. |
| 30 | + javaScriptFilter struct { |
| 31 | + vm *javaScriptVM |
| 32 | + requestHeaders map[string]string |
| 33 | + responseHeaders map[string]string |
| 34 | + } |
| 35 | + javaScriptVM struct { |
| 36 | + *goja.Runtime |
| 37 | + mux sync.Mutex |
| 38 | + onRequestHeaders goja.Callable |
| 39 | + onResponseHeaders goja.Callable |
| 40 | + } |
| 41 | +) |
| 42 | + |
| 43 | +func newJavaScriptFilterConfig(userCode string) gosdk.HttpFilterConfig { |
| 44 | + c := &javaScriptFilterConfig{} |
| 45 | + |
| 46 | + for i := range numberOfVMPool { |
| 47 | + vm, err := newJavaScriptVM(userCode, os.Stdout) |
| 48 | + if err != nil { |
| 49 | + log.Printf("failed to create JavaScript VM: %v", err) |
| 50 | + return nil |
| 51 | + } |
| 52 | + c.vms[i] = vm |
| 53 | + } |
| 54 | + return c |
| 55 | +} |
| 56 | + |
| 57 | +func newJavaScriptVM(script string, w io.Writer) (*javaScriptVM, error) { |
| 58 | + vm := goja.New() |
| 59 | + console := vm.NewObject() |
| 60 | + err := console.Set("log", func(call goja.FunctionCall) goja.Value { |
| 61 | + args := make([]interface{}, 0, len(call.Arguments)) |
| 62 | + for _, a := range call.Arguments { |
| 63 | + args = append(args, a.Export()) |
| 64 | + } |
| 65 | + _, _ = fmt.Fprint(w, args...) |
| 66 | + return goja.Undefined() |
| 67 | + }) |
| 68 | + if err != nil { |
| 69 | + return nil, fmt.Errorf("failed to set console.log: %w", err) |
| 70 | + } |
| 71 | + err = vm.Set("console", console) |
| 72 | + if err != nil { |
| 73 | + return nil, fmt.Errorf("failed to set console: %w", err) |
| 74 | + } |
| 75 | + |
| 76 | + _, err = vm.RunString(script) |
| 77 | + if err != nil { |
| 78 | + return nil, fmt.Errorf("failed to run script: %w", err) |
| 79 | + } |
| 80 | + |
| 81 | + // Call OnConfigure. |
| 82 | + onConfigure, ok := goja.AssertFunction(vm.GlobalObject().Get(javaScriptExportedSymbolOnConfig)) |
| 83 | + if !ok { |
| 84 | + return nil, fmt.Errorf("failed to get %s function", javaScriptExportedSymbolOnConfig) |
| 85 | + } |
| 86 | + _, err = onConfigure(goja.Undefined()) |
| 87 | + if err != nil { |
| 88 | + return nil, fmt.Errorf("failed to call %s function: %w", javaScriptExportedSymbolOnConfig, err) |
| 89 | + } |
| 90 | + |
| 91 | + ret := &javaScriptVM{Runtime: vm} |
| 92 | + // Check two exported functions. |
| 93 | + ret.onRequestHeaders, ok = goja.AssertFunction(vm.GlobalObject().Get(javaScriptExportedSymbolOnRequestHeaders)) |
| 94 | + if !ok { |
| 95 | + return nil, fmt.Errorf("failed to get %s function", javaScriptExportedSymbolOnRequestHeaders) |
| 96 | + } |
| 97 | + ret.onResponseHeaders, ok = goja.AssertFunction(vm.GlobalObject().Get(javaScriptExportedSymbolOnResponseHeaders)) |
| 98 | + if !ok { |
| 99 | + return nil, fmt.Errorf("failed to get %s function", javaScriptExportedSymbolOnResponseHeaders) |
| 100 | + } |
| 101 | + return ret, nil |
| 102 | +} |
| 103 | + |
| 104 | +// NewFilter implements [gosdk.HttpFilterConfig]. |
| 105 | +func (p *javaScriptFilterConfig) NewFilter() gosdk.HttpFilter { |
| 106 | + vm := p.vms[rand.Intn(numberOfVMPool)] |
| 107 | + return &javaScriptFilter{vm: vm, requestHeaders: make(map[string]string), responseHeaders: make(map[string]string)} |
| 108 | +} |
| 109 | + |
| 110 | +// RequestHeaders implements [gosdk.HttpFilter]. |
| 111 | +func (p *javaScriptFilter) RequestHeaders(e gosdk.EnvoyHttpFilter, _ bool) gosdk.RequestHeadersStatus { |
| 112 | + headers := e.GetRequestHeaders() |
| 113 | + for k, vs := range headers { |
| 114 | + p.requestHeaders[k] = vs[0] |
| 115 | + } |
| 116 | + p.vm.mux.Lock() |
| 117 | + defer p.vm.mux.Unlock() |
| 118 | + vm := p.vm |
| 119 | + obj := vm.NewObject() |
| 120 | + _ = obj.Set("getRequestHeader", func(call goja.FunctionCall) goja.Value { |
| 121 | + if len(call.Arguments) < 1 { |
| 122 | + return vm.ToValue("") |
| 123 | + } |
| 124 | + key := call.Argument(0).String() |
| 125 | + return vm.ToValue(p.requestHeaders[key]) |
| 126 | + }) |
| 127 | + _ = obj.Set("setRequestHeader", func(call goja.FunctionCall) goja.Value { |
| 128 | + if len(call.Arguments) < 2 { |
| 129 | + return goja.Undefined() |
| 130 | + } |
| 131 | + key := call.Argument(0).String() |
| 132 | + value := call.Argument(1).String() |
| 133 | + p.requestHeaders[key] = value |
| 134 | + e.SetRequestHeader(key, []byte(value)) |
| 135 | + return goja.Undefined() |
| 136 | + }) |
| 137 | + if _, err := vm.onRequestHeaders(goja.Undefined(), obj); err != nil { |
| 138 | + log.Printf("failed to call %s: %v", javaScriptExportedSymbolOnRequestHeaders, err) |
| 139 | + return gosdk.RequestHeadersStatusStopIteration |
| 140 | + } |
| 141 | + return gosdk.RequestHeadersStatusContinue |
| 142 | +} |
| 143 | + |
| 144 | +// ResponseHeaders implements [gosdk.HttpFilter]. |
| 145 | +func (p *javaScriptFilter) ResponseHeaders(e gosdk.EnvoyHttpFilter, _ bool) gosdk.ResponseHeadersStatus { |
| 146 | + headers := e.GetResponseHeaders() |
| 147 | + for k, vs := range headers { |
| 148 | + p.responseHeaders[k] = vs[0] |
| 149 | + } |
| 150 | + p.vm.mux.Lock() |
| 151 | + defer p.vm.mux.Unlock() |
| 152 | + vm := p.vm |
| 153 | + obj := vm.NewObject() |
| 154 | + _ = obj.Set("getRequestHeader", func(call goja.FunctionCall) goja.Value { |
| 155 | + if len(call.Arguments) < 1 { |
| 156 | + return vm.ToValue("") |
| 157 | + } |
| 158 | + key := call.Argument(0).String() |
| 159 | + return vm.ToValue(p.requestHeaders[key]) |
| 160 | + }) |
| 161 | + |
| 162 | + // Setting request header in response phase is not allowed. |
| 163 | + |
| 164 | + _ = obj.Set("getResponseHeader", func(call goja.FunctionCall) goja.Value { |
| 165 | + if len(call.Arguments) < 1 { |
| 166 | + return vm.ToValue("") |
| 167 | + } |
| 168 | + key := call.Argument(0).String() |
| 169 | + return vm.ToValue(p.responseHeaders[key]) |
| 170 | + }) |
| 171 | + _ = obj.Set("setResponseHeader", func(call goja.FunctionCall) goja.Value { |
| 172 | + if len(call.Arguments) < 2 { |
| 173 | + return goja.Undefined() |
| 174 | + } |
| 175 | + key := call.Argument(0).String() |
| 176 | + value := call.Argument(1).String() |
| 177 | + p.responseHeaders[key] = value |
| 178 | + e.SetResponseHeader(key, []byte(value)) |
| 179 | + return goja.Undefined() |
| 180 | + }) |
| 181 | + if _, err := vm.onResponseHeaders(goja.Undefined(), obj); err != nil { |
| 182 | + log.Printf("failed to call %s: %v", javaScriptExportedSymbolOnResponseHeaders, err) |
| 183 | + return gosdk.ResponseHeadersStatusStopIteration |
| 184 | + } |
| 185 | + return gosdk.ResponseHeadersStatusContinue |
| 186 | +} |
| 187 | + |
| 188 | +// Destroy implements [gosdk.HttpFilterConfig]. |
| 189 | +func (p *javaScriptFilterConfig) Destroy() {} |
| 190 | + |
| 191 | +// Scheduled implements gosdk.HttpFilter. |
| 192 | +func (p *javaScriptFilter) Scheduled(gosdk.EnvoyHttpFilter, uint64) {} |
| 193 | + |
| 194 | +// Destroy implements [gosdk.HttpFilter]. |
| 195 | +func (p *javaScriptFilter) Destroy() {} |
| 196 | + |
| 197 | +// RequestBody implements [gosdk.HttpFilter]. |
| 198 | +func (p *javaScriptFilter) RequestBody(gosdk.EnvoyHttpFilter, bool) gosdk.RequestBodyStatus { |
| 199 | + return gosdk.RequestBodyStatusContinue |
| 200 | +} |
| 201 | + |
| 202 | +// ResponseBody implements [gosdk.HttpFilter]. |
| 203 | +func (p *javaScriptFilter) ResponseBody(gosdk.EnvoyHttpFilter, bool) gosdk.ResponseBodyStatus { |
| 204 | + return gosdk.ResponseBodyStatusContinue |
| 205 | +} |
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