damccorm commented on a change in pull request #16153: URL: https://github.com/apache/beam/pull/16153#discussion_r765174802
########## File path: sdks/go/pkg/beam/core/runtime/xlangx/expansionx/download.go ########## @@ -0,0 +1,130 @@ +// Licensed to the Apache Software Foundation (ASF) under one or more +// contributor license agreements. See the NOTICE file distributed with +// this work for additional information regarding copyright ownership. +// The ASF licenses this file to You 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 expansionx contains utilities for starting expansion services for +// cross-language transforms. +package expansionx + +import ( + "errors" + "fmt" + "io" + "net/http" + "os" + "os/user" + "path/filepath" + "strings" +) + +// URL is a type used to differentiate between strings and URLs +type URL string + +const ( + apacheRepository = URL("https://repo.maven.apache.org/maven2";) + beamGroupID = "org/apache/beam" + jarCache = "~/.apache_beam/cache/jars" +) + +// GetBeamJar checks a temporary directory for the desired Beam JAR, downloads the +// appropriate JAR from Maven if not present, then returns the file path to the +// JAR. +func GetBeamJar(gradleTarget, version string) (string, error) { + strippedTarget := dropEndOfGradleTarget(gradleTarget) + baseURL, jarName := getURLForBeamJar(strippedTarget, version) + + fullURL := baseURL + URL(jarName) + + resp, err := http.Get(string(fullURL)) + if err != nil { + return "", err + } + defer resp.Body.Close() + + if resp.StatusCode != 200 { + return "", fmt.Errorf("Received non 200 response code, got %v", resp.StatusCode) + } + + cacheDir := getCacheDir() + err = checkDir(cacheDir) + if err != nil { + return "", err + } + + jarPath := filepath.Join(cacheDir, jarName) + + if jarExists(jarPath) { + return jarPath, nil + } + + file, err := os.Create(jarPath) + if err != nil { + return "", err + } + + _, err = io.Copy(file, resp.Body) + if err != nil { + return "", err + } + + return jarPath, nil +} + +// getURLForBeamJar builds the Maven URL for the JAR and the JAR name, returning both +// separately so the JAR name can be used for saving the file later. +func getURLForBeamJar(gradleTarget, version string) (URL, string) { + baseURL := URL(apacheRepository + "/" + beamGroupID + "/") + fullTarget := "beam" + gradleTarget + targetPath := strings.ReplaceAll(fullTarget, ":", "-") + jarName := strings.ReplaceAll(fullTarget, ":", "-") + "-" + version + ".jar" + return baseURL + URL(targetPath) + "/" + URL(version) + "/", jarName +} + +// dropEndOfGradleTarget drops the last substring off of the gradle target. This +// is used to build the Maven target and JAR name (the last substring on the gradle) +// command is usually a directive, not a reference to the desired JAR.) +func dropEndOfGradleTarget(gradleTarget string) string { + elms := strings.Split(gradleTarget, ":") + droppedSuffix := elms[:len(elms)-1] + return strings.Join(droppedSuffix, ":") +} + +// getCacheDir returns the absolute file path of the JAR cache from the user's HOME +// directory. +func getCacheDir() string { + usr, _ := user.Current() + return filepath.Join(usr.HomeDir, jarCache[2:]) +} + +// checkDir checks that a given directory exists, then creates the directory and +// parent directories if it does not. Returns another error if the returned +// error from os.Stat is not an ErrNotExist error. +func checkDir(dirPath string) error { Review comment: I think they return more or less the same error in that case - stat returns `stat path/to/dir: permission denied`, and MkdirAll returns `mkdir path/to/dir: permission denied` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
