reduce artifacts exists calls on iOS builds

Author: coado

packages/react-native/scripts/ios-prebuild/hermes.js

@@ -19,6 +19,7 @@ const pipeline = promisify(stream.pipeline);
 const hermesLog = createLogger('Hermes');
 const MAVEN_CENTRAL_REPOSITORY = 'https://repo1.maven.org/maven2';
 const REACT_NATIVE_MAVEN_CACHE_REPOSITORY = 'https://rnmaven.swmtest.xyz';
+const artifactExistenceCache = new Map();
 
 /*::
 import type {BuildFlavor, Destination, Platform} from './types';
@@ -193,16 +194,25 @@ async function getTarballUrl(
   version /*: string */,
   buildType /*: BuildFlavor */,
 ) /*: Promise<string> */ {
+  const existingUrl = await findExistingTarballUrl(version, buildType);
+  if (existingUrl != null) {
+    return existingUrl;
+  }
+
+  return getTarballUrls(version, buildType)[0];
+}
+
+async function findExistingTarballUrl(
+  version /*: string */,
+  buildType /*: BuildFlavor */,
+) /*: Promise<?string> */ {
   const candidates = getTarballUrls(version, buildType);
   for (const url of candidates) {
-    console.log(`Checking if Hermes artifact exists at URL: ${url}`);
     if (await hermesArtifactExists(url)) {
-      console.log(`Found Hermes artifact at URL: ${url}`);
       return url;
     }
-    console.log(`Hermes artifact not found at URL: ${url}`);
   }
-  return candidates[0];
+  return null;
 }
 
 function getTarballUrls(
@@ -233,13 +243,20 @@ function getMavenRepositoryUrls() /*: Array<string> */ {
 async function hermesArtifactExists(
   tarballUrl /*: string */,
 ) /*: Promise<boolean> */ {
+  if (artifactExistenceCache.has(tarballUrl)) {
+    return artifactExistenceCache.get(tarballUrl);
+  }
+
   try {
     const response /*: Response */ = await fetch(tarballUrl, {
       method: 'HEAD',
     });
 
-    return response.status === 200;
+    const exists = response.status === 200;
+    artifactExistenceCache.set(tarballUrl, exists);
+    return exists;
   } catch (e) {
+    artifactExistenceCache.set(tarballUrl, false);
     return false;
   }
 }
@@ -256,8 +273,7 @@ async function hermesSourceType(
     return HermesEngineSourceTypes.LOCAL_PREBUILT_TARBALL;
   }
 
-  const tarballUrl = await getTarballUrl(version, buildType);
-  if (await hermesArtifactExists(tarballUrl)) {
+  if ((await findExistingTarballUrl(version, buildType)) != null) {
     hermesLog(`Using download prebuild ${buildType} tarball`);
     return HermesEngineSourceTypes.DOWNLOAD_PREBUILD_TARBALL;
   }

packages/react-native/scripts/ios-prebuild/reactNativeDependencies.js

@@ -22,6 +22,7 @@ const pipeline = promisify(stream.pipeline);
 const dependencyLog = createLogger('ReactNativeDependencies');
 const MAVEN_CENTRAL_REPOSITORY = 'https://repo1.maven.org/maven2';
 const REACT_NATIVE_MAVEN_CACHE_REPOSITORY = 'https://rnmaven.swmtest.xyz';
+const artifactExistenceCache = new Map();
 
 /**
  * Downloads ReactNativeDependencies artifacts from the specified version and build type. If you want to specify a specific
@@ -184,13 +185,25 @@ async function getTarballUrl(
   version /*: string */,
   buildType /*: BuildFlavor */,
 ) /*: Promise<string> */ {
+  const existingUrl = await findExistingTarballUrl(version, buildType);
+  if (existingUrl != null) {
+    return existingUrl;
+  }
+
+  return getTarballUrls(version, buildType)[0];
+}
+
+async function findExistingTarballUrl(
+  version /*: string */,
+  buildType /*: BuildFlavor */,
+) /*: Promise<?string> */ {
   const candidates = getTarballUrls(version, buildType);
   for (const url of candidates) {
     if (await reactNativeDependenciesArtifactExists(url)) {
       return url;
     }
   }
-  return candidates[0];
+  return null;
 }
 
 function getTarballUrls(
@@ -237,13 +250,20 @@ async function getNightlyTarballUrl(
 async function reactNativeDependenciesArtifactExists(
   tarballUrl /*: string */,
 ) /*: Promise<boolean> */ {
+  if (artifactExistenceCache.has(tarballUrl)) {
+    return artifactExistenceCache.get(tarballUrl);
+  }
+
   try {
     const response /*: Response */ = await fetch(tarballUrl, {
       method: 'HEAD',
     });
 
-    return response.status === 200;
+    const exists = response.status === 200;
+    artifactExistenceCache.set(tarballUrl, exists);
+    return exists;
   } catch (e) {
+    artifactExistenceCache.set(tarballUrl, false);
     return false;
   }
 }
@@ -255,8 +275,7 @@ async function reactNativeDependenciesSourceType(
   version /*: string */,
   buildType /*: BuildFlavor */,
 ) /*: Promise<ReactNativeDependenciesEngineSourceType> */ {
-  const tarballUrl = await getTarballUrl(version, buildType);
-  if (await reactNativeDependenciesArtifactExists(tarballUrl)) {
+  if ((await findExistingTarballUrl(version, buildType)) != null) {
     dependencyLog(`Using download prebuild ${buildType} tarball`);
     return ReactNativeDependenciesEngineSourceTypes.DOWNLOAD_PREBUILD_TARBALL;
   }