fix: workaround for crashes loading v8 snapshot (#101)

package.json

@@ -83,14 +83,15 @@
     "url-search-params": "^0.10.0"
   },
   "dependencies": {
+    "@types/semver": "^5.5.0",
     "@types/sharp": "^0.17.6",
     "ansi-colors": "^1.1.0",
     "axios": "^0.18.0",
+    "better-sqlite3": "^4.1.4",
     "chokidar": "^2.0.4",
     "cli-table3": "^0.5.0",
     "commandpost": "^1.3.0",
     "console-log-level": "^1.4.0",
-    "better-sqlite3": "^4.1.4",
     "fs-extra": "^5.0.0",
     "glob": "^7.1.2",
     "glossy": "0.x.x",
@@ -102,7 +103,8 @@
     "promise.prototype.finally": "^3.1.0",
     "promptly": "^3.0.3",
     "segfault-handler": "^1.0.1",
-    "sharp": "^0.20.1",
+    "semver": "^5.5.0",
+    "sharp": "^0.20.5",
     "source-map": "^0.6.1",
     "tar-fs": "^1.16.0",
     "uglifyjs-webpack-plugin": "^1.2.2",
@@ -129,4 +131,4 @@
     ],
     "all": true
   }
-}
+}

src/local_runtime.ts

@@ -29,8 +29,8 @@ export class LocalRuntime implements Runtime {
     public bridge: Bridge,
     options: LocalRuntimeOptions = {}
   ) {
-    if (!v8Env.snapshot)
-      throw new Error("base snapshot is not ready, maybe you need to compile v8env?")
+    //if (!v8Env.snapshot)
+    //  throw new Error("base snapshot is not ready, maybe you need to compile v8env?")
 
     console.log("new runtime, app:", app.name, app.sourceHash)
 
@@ -79,6 +79,13 @@ export class LocalRuntime implements Runtime {
     if (current)
       current.release()
     const context = this.isolate.createContextSync({ inspector: !!this.options.inspect })
+
+    if (!v8Env.snapshot) {
+      const start = Date.now()
+      const script = this.isolate.compileScriptSync(v8Env.source, { filename: "bundle.js" })
+      script.runSync(context)
+      console.log("v8env loaded in", Date.now() - start, "ms")
+    }
     const g = context.global
     g.setSync("global", g.derefInto())
     g.setSync('_log', new ivm.Reference(function (lvl: string, ...args: any[]) {
@@ -107,6 +114,7 @@ export class LocalRuntime implements Runtime {
       this.app = app
       if (this.lastSourceHash != "") // we had not setup the context
         this.context = this.resetContext(this.context)
+
       await this.runApp(app)
       this.lastSourceHash = app.sourceHash
     }

src/v8env.ts

@@ -1,5 +1,6 @@
 import * as path from 'path'
 import * as fs from 'fs'
+import * as semver from 'semver'
 
 import * as webpack from 'webpack'
 
@@ -12,7 +13,7 @@ import * as ivm from 'isolated-vm';
 let v8EnvHash = "";
 let v8EnvCode = "";
 let v8EnvSourceMap = "";
-let v8EnvSnapshot: ivm.ExternalCopy<ArrayBuffer>;
+let v8EnvSnapshot: ivm.ExternalCopy<ArrayBuffer> | undefined;
 
 const v8dist = path.join(__dirname, '..', 'dist', 'v8env.js')
 const v8distSnapshot = path.join(__dirname, '..', 'dist', 'v8env.bin')
@@ -23,17 +24,28 @@ if (fs.existsSync(v8dist)) {
   v8EnvHash = createHash("sha1").update(v8EnvCode).digest("hex")
 }
 
-if (fs.existsSync(v8distSnapshot)) {
-  v8EnvSnapshot = new ivm.ExternalCopy(<ArrayBuffer>fs.readFileSync(v8distSnapshot).buffer)
-} else if (v8EnvCode) {
-  v8EnvSnapshot = ivm.Isolate.createSnapshot([{
-    code: v8EnvCode,
-    filename: 'dist/v8env.js'
-  }])
+const v8SnapshotsEnabled = semver.lt(process.version, '10.4.0')
+if (!v8SnapshotsEnabled) {
+  console.warn("can't use v8 snapshots with this version of node, boot will be slower", process.version)
 }
+else {
+  console.log("v8 snapshots enabled")
+
+  if (fs.existsSync(v8distSnapshot)) {
+    console.log("loading snapshot:", v8distSnapshot)
+    v8EnvSnapshot = new ivm.ExternalCopy(<ArrayBuffer>fs.readFileSync(v8distSnapshot).buffer)
+  } else if (v8EnvCode) {
+    console.log("building snapshot")
+    v8EnvSnapshot = ivm.Isolate.createSnapshot([{
+      code: v8EnvCode,
+      filename: 'dist/v8env.js'
+    }])
+  }
+
 
-if (fs.existsSync(v8mapDist)) {
-  v8EnvSourceMap = fs.readFileSync(v8mapDist).toString()
+  if (fs.existsSync(v8mapDist)) {
+    v8EnvSourceMap = fs.readFileSync(v8mapDist).toString()
+  }
 }
 
 export class V8Environment extends EventEmitter {
@@ -46,7 +58,7 @@ export class V8Environment extends EventEmitter {
   }
 
   get isReady() {
-    return !!v8Env && !!v8EnvSnapshot
+    return !!v8Env && (!!v8EnvSnapshot || !v8SnapshotsEnabled)
   }
 
   get source() {