// Copyright © 2019 The Things Network Foundation, The Things Industries B.V. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // Package javascript implements a Javascript scripting engine. package javascript import ( "context" "runtime/trace" "time" "github.com/robertkrimen/otto" "go.thethings.network/lorawan-stack/v3/pkg/errors" "go.thethings.network/lorawan-stack/v3/pkg/scripting" ) type js struct { options scripting.Options } // New returns a new Javascript scripting engine. func New(options scripting.Options) scripting.Engine { return &js{options} } var errRuntime = errors.Define("runtime", "runtime error") // Run executes the Javascript script in the environment env and returns the output. func (j *js) Run(ctx context.Context, script string, env map[string]interface{}) (val interface{}, err error) { defer trace.StartRegion(ctx, "run javascript").End() start := time.Now() defer func() { runLatency.Observe(time.Since(start).Seconds()) if err != nil { runs.WithLabelValues("error").Inc() } else { runs.WithLabelValues("ok").Inc() } }() vm := otto.New() vm.SetStackDepthLimit(j.options.StackDepthLimit) err = vm.Set("env", env) if err != nil { return } defer func() { if caught := recover(); caught != nil { switch val := caught.(type) { case error: err = errRuntime.WithCause(val) default: err = errRuntime } return } }() vm.Interrupt = make(chan func(), 1) ctx, cancel := context.WithTimeout(ctx, j.options.Timeout) defer cancel() go func() { <-ctx.Done() vm.Interrupt <- func() { panic(context.DeadlineExceeded) } }() output, err := vm.Run(script) if err != nil { return nil, errRuntime.WithCause(err) } return output.Export() }