code: /**
   * This file is part of Eclipse Steady.
   *
   * 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.
   *
   * SPDX-License-Identifier: Apache-2.0
   * SPDX-FileCopyrightText: Copyright (c) 2018-2020 SAP SE or an SAP affiliate company and Eclipse Steady contributors
   */
  package org.eclipse.steady.python.pip;
  
  import java.io.IOException;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.logging.log4j.Logger;
  import org.eclipse.steady.python.ProcessWrapperException;
  import org.eclipse.steady.shared.util.FileUtil;
  import org.eclipse.steady.shared.util.StringUtil;
  
  /**
   * PyWrapper class.
   */
  public class PyWrapper {
  
    private static final Logger log = org.apache.logging.log4j.LogManager.getLogger();
  
    private Path pathToPython = null;
  
    private Path logDir = null;
  
    /**
     * Assumes that the Python executable is part of the PATH environment variable.
     *
     * @throws org.eclipse.steady.python.ProcessWrapperException if any.
     */
    public PyWrapper() throws ProcessWrapperException {
      this(Paths.get("python"), null);
    }
  
    /**
     * Creates a new wrapper for the python executable at the given path.
     *
     * @param _path_to_python a {@link java.nio.file.Path} object.
     * @param _log_dir a {@link java.nio.file.Path} object.
     * @throws org.eclipse.steady.python.ProcessWrapperException if any.
     */
    public PyWrapper(Path _path_to_python, Path _log_dir) throws ProcessWrapperException {
      this.pathToPython = _path_to_python;
      if (_log_dir != null) {
        this.logDir = _log_dir;
      } else {
        try {
          FileUtil.createTmpDir("vulas-pip-");
        } catch (IOException e) {
          throw new ProcessWrapperException("Cannot create tmp directory: " + e.getMessage());
        }
      }
    }
  
    /**
     * isAvailable.
     *
     * @return a boolean.
     */
    public boolean isAvailable() {
      boolean exists = false;
      try {
        final Process p = new ProcessBuilder(this.pathToPython.toString()).start();
        final int exit_code = p.waitFor();
        exists = exit_code == 0;
      } catch (IOException ioe) {
        log.error("Error calling [python]: " + ioe.getMessage(), ioe);
      } catch (InterruptedException ie) {
        log.error("Error calling [python]: " + ie.getMessage(), ie);
      }
      return exists;
    }
  
    /**
     * Runs a Python script.
     *
     * @param _script a {@link java.nio.file.Path} object.
     * @param _args a {@link java.util.List} object.
     * @return an int representing the exit code.
     */
    public int runScript(Path _script, List<String> _args) {
      int exit_code = -1;
  
      // Complete command line call
      final List<String> list = new ArrayList<String>();
      list.add(this.pathToPython.toString());
      list.add(_script.toString());
      list.addAll(_args);
  
      final String script_name = _script.getFileName().toString();
  
      try {
        // Perform call
        final ProcessBuilder pb = new ProcessBuilder(list);
  
        // Create temp. directory for out and err streams
        final Path out = Paths.get(logDir.toString(), "python-" + script_name + "-out.txt");
        final Path err = Paths.get(logDir.toString(), "python-" + script_name + "-err.txt");
  
        // Redirect out and err
        pb.redirectOutput(out.toFile());
        pb.redirectError(err.toFile());
  
        // Start and wait
        final Process process = pb.start();
        exit_code = process.waitFor();
  
        // Success: Parse output and call pip show <package>
        if (exit_code != 0) {
          final String error_msg = FileUtil.readFile(err);
          log.error("Error calling [python " + StringUtil.join(list, " ") + "]: " + error_msg);
        }
      } catch (IOException ioe) {
        log.error("Error calling [python " + StringUtil.join(list, " ") + "]: " + ioe.getMessage());
      } catch (InterruptedException ie) {
        log.error("Error calling [python " + StringUtil.join(list, " ") + "]: " + ie.getMessage());
      }
      return exit_code;
    }
  }
  