func downloadAndUnpackJar()

in wrappers/golang/pgadapter.go [459:540]
71 lines of code
23 McCabe index (conditional complexity)

func downloadAndUnpackJar(ctx context.Context, config Config) (string, error) {
	ds := config.ExecutionEnvironment.(*Java).DownloadSettings
	var err error
	var dst string
	if ds.DownloadLocation == "" {
		dst, err = os.UserCacheDir()
		if err != nil {
			return "", err
		}
		dst = filepath.Join(dst, "pgadapter-downloads")
	} else {
		dst = ds.DownloadLocation
	}
	if !ds.DisableAutomaticDownload {
		if config.Version == "" {
			dst = filepath.Join(dst, "pgadapter-latest")
		} else {
			dst = filepath.Join(dst, fmt.Sprintf("pgadapter-%s", config.Version))
		}
		if err := os.MkdirAll(dst, 0755); err != nil {
			return "", err
		}
	}

	jarFi, jarErr := os.Stat(filepath.Join(dst, "pgadapter.jar"))
	libFi, libErr := os.Stat(filepath.Join(dst, "lib"))
	// If automatic downloads are disabled, then PGAdapter must already exist in the given location.
	if ds.DisableAutomaticDownload {
		if jarErr != nil {
			return "", jarErr
		}
		if libErr != nil {
			return "", libErr
		}
		// All seems OK, just return the download location.
		return ds.DownloadLocation, nil
	}

	var url string
	if config.Version == "" {
		url = jarBaseDownloadUrl + latestJarFileName
	} else {
		url = jarBaseDownloadUrl + fmt.Sprintf(versionedJarFileName, config.Version)
	}
	resp, err := http.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()
	var lastModified time.Time
	lastModifiedString := resp.Header.Get("Last-Modified")
	if lastModifiedString != "" {
		lastModified, _ = http.ParseTime(lastModifiedString)
	}

	// Check if we need to download PGAdapter.
	if jarErr == nil && libErr == nil {
		// Both files seem to exist. Check the file info.
		if jarFi != nil && libFi != nil {
			// Check the types of the files and the last modified date.
			if libFi.IsDir() && !jarFi.IsDir() && libFi.ModTime().After(lastModified) && jarFi.ModTime().After(lastModified) {
				// Both the pgadapter.jar file and the lib dir exist and are up-to-date. Use these.
				return dst, nil
			}
		}
	}
	tarGzFile := filepath.Join(dst, "pgadapter.tar.gz")

	out, err := os.Create(tarGzFile)
	if err != nil {
		return "", err
	}
	defer out.Close()

	if _, err := io.Copy(out, resp.Body); err != nil {
		return "", err
	}
	if err := unpackJar(ctx, tarGzFile); err != nil {
		return "", err
	}
	return dst, err
}