minifi-c2/minifi-c2-cache/minifi-c2-cache-filesystem/src/main/java/org/apache/nifi/minifi/c2/cache/filesystem/FileSystemConfigurationCache.java

/*
 * 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 org.apache.nifi.minifi.c2.cache.filesystem;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

import org.apache.nifi.minifi.c2.api.InvalidParameterException;
import org.apache.nifi.minifi.c2.api.cache.ConfigurationCache;
import org.apache.nifi.minifi.c2.api.cache.ConfigurationCacheFileInfo;
import org.apache.nifi.minifi.c2.api.util.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Implementation of {@link ConfigurationCache} that uses the local file
 * system for caching configurations.
 *
 */
public class FileSystemConfigurationCache implements ConfigurationCache {
    private static final Logger logger = LoggerFactory.getLogger(FileSystemConfigurationCache.class);

    private final Path pathRoot;
    private final String pathPattern;

    /**
     * Creates a new cache.
     * @param pathRoot The root path for configurations. This path will be appended
     * to the environment variable <code>C2_SERVER_HOME</code>.
     * @param pathPattern The pattern to determine the path.
     * @throws IOException Thrown if the path cannot be created.
     */
    public FileSystemConfigurationCache(String pathRoot, String pathPattern) throws IOException {
        this.pathRoot = Paths.get(System.getenv("C2_SERVER_HOME")).resolve(pathRoot).toAbsolutePath();
        Files.createDirectories(this.pathRoot);
        this.pathPattern = pathPattern;
    }

    /**
     * Resolves a parent {@link Path path} and child directory.
     * @param parent The parent {@link Path path}.
     * @param s The child directory.
     * @return The resolved {@link Path}.
     * @throws InvalidParameterException Thrown if the child directory is
     * not actually a child directory of the parent.
     */
    protected Path resolveChildAndVerifyParent(Path parent, String s) throws InvalidParameterException {
        Path child = parent.resolve(s).toAbsolutePath();
        if (child.toAbsolutePath().getParent().equals(parent)) {
            return child;
        } else {
            throw new InvalidParameterException("Path entry " + s + " not child of " + parent);
        }
    }

    @Override
    public ConfigurationCacheFileInfo getCacheFileInfo(String contentType, Map<String, List<String>> parameters) throws InvalidParameterException {
        String pathString = pathPattern;
        for (Map.Entry<String, List<String>> entry : parameters.entrySet()) {
            if (entry.getValue().size() != 1) {
                throw new InvalidParameterException("Multiple values for same parameter not supported in this provider.");
            }
            pathString = pathString.replaceAll(Pattern.quote("${" + entry.getKey() + "}"), entry.getValue().get(0));
        }
        pathString = pathString + "." + contentType.replace('/', '.');
        String[] split = pathString.split("/");
        for (String s1 : split) {
            int openBrace = s1.indexOf("${");
            if (openBrace >= 0 && openBrace < s1.length() + 2) {
                int closeBrace = s1.indexOf("}", openBrace + 2);
                if (closeBrace >= 0) {
                    throw new InvalidParameterException("Found unsubstituted variable " + s1.substring(openBrace + 2, closeBrace));
                }
            }
        }
        String[] splitPath = split;
        Path path = pathRoot.toAbsolutePath();
        for (int i = 0; i < splitPath.length - 1; i++) {
            String s = splitPath[i];
            path = resolveChildAndVerifyParent(path, s);
        }
        Pair<Path, String> dirPathAndFilename = new Pair<>(path, splitPath[splitPath.length - 1]);
        if (logger.isDebugEnabled()) {
            StringBuilder message = new StringBuilder("Parameters {");
            message.append(parameters.entrySet().stream().map(e -> e.getKey() + ": [" + String.join(", ", e.getValue()) + "]").collect(Collectors.joining(", ")));
            message.append("} -> ");
            message.append(dirPathAndFilename.getFirst().resolve(dirPathAndFilename.getSecond()).toAbsolutePath());
            logger.debug(message.toString());
        }
        return new FileSystemCacheFileInfoImpl(this, dirPathAndFilename.getFirst(), dirPathAndFilename.getSecond() + ".v");
    }
}