com.hp.autonomy.frontend.configuration.BaseConfigFileService Maven / Gradle / Ivy
/*
* Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
* Licensed under the MIT License (the "License"); you may not use this file except in compliance with the License.
*/
package com.hp.autonomy.frontend.configuration;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ser.FilterProvider;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.concurrent.atomic.AtomicReference;
import javax.annotation.PostConstruct;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.jasypt.util.text.TextEncryptor;
/**
* Reference implementation of {@link ConfigFileService}, which outputs configuration objects as JSON files.
* An additional type bound is placed on the configuration object this class uses.
*
* Clients of this API should extend {@link AbstractAuthenticatingConfigFileService} or
* {@link AbstractUnauthenticatingConfigFileService}, depending on their needs.
*
* This class requires that a default config file be available at runtime.
*
* Operations on the Config object are thread safe.
*
* @param The type of the Configuration object. If it extends {@link PasswordsConfig}, passwords will be encrypted
* and decrypted when the file is written and read respectively.
*
*/
@Slf4j
public abstract class BaseConfigFileService> implements ConfigFileService {
private String configFileLocation;
private String configFileName;
private String defaultConfigFile;
// Use AtomicReference for thread safety
private final AtomicReference config = new AtomicReference<>(null);
private ObjectMapper mapper;
private TextEncryptor textEncryptor;
private final Object updateLock = new Object();
private FilterProvider filterProvider;
private ValidationService validationService;
/**
* Initialises the service
*
* @throws IllegalStateException If an error occurs which prevent service initialization
* @throws Exception If an unspecified error occurs
*/
// Exception thrown by method in library
@SuppressWarnings("ProhibitedExceptionDeclared")
@PostConstruct
public void init() throws Exception {
final String configFileLocation = getConfigFileLocation();
T fileConfig = getEmptyConfig();
boolean fileExists = false;
if(StringUtils.isNotBlank(configFileLocation)) {
log.debug("Using {} as config file location", configFileLocation);
try(Reader reader = new BufferedReader(new InputStreamReader(new FileInputStream(configFileLocation), "UTF-8"))){
fileConfig = mapper.readValue(reader, getConfigClass());
if(fileConfig instanceof PasswordsConfig) {
fileConfig = ((PasswordsConfig) fileConfig).withDecryptedPasswords(textEncryptor);
}
fileExists = true;
}
catch(final FileNotFoundException e) {
log.warn("Config file not found, using empty configuration object");
}
catch(final IOException e) {
log.error("Error reading config file at {}", configFileLocation);
log.error("Recording stack trace", e);
// throw this so we don't continue to start the webapp
throw new IllegalStateException("Could not initialize configuration", e);
}
}
if (StringUtils.isNotBlank(defaultConfigFile)) {
try (InputStream defaultConfigInputStream = getClass().getResourceAsStream(defaultConfigFile)) {
if (defaultConfigInputStream != null) {
final T defaultConfig = mapper.readValue(defaultConfigInputStream, getConfigClass());
fileConfig = fileConfig.merge(defaultConfig);
if (!fileExists) {
fileConfig = generateDefaultLogin(fileConfig);
try {
writeOutConfigFile(fileConfig, configFileLocation);
} catch (final IOException e) {
throw new IllegalStateException("Could not initialize configuration", e);
}
}
}
} catch (final IOException e) {
log.error("Error reading default config file", e);
// throw this so we don't continue to start the webapp
throw new IllegalStateException("Could not initialize configuration", e);
}
}
try {
fileConfig.basicValidate();
} catch (final ConfigException e) {
log.error("Config validation failed in " + e);
throw new IllegalStateException("Could not initialize configuration", e);
}
if (fileConfig.equals(getEmptyConfig())) {
log.info("Cannot read value from {}", configFileLocation);
log.debug("Environment is {}", System.getenv());
} else {
config.set(fileConfig);
postInitialise(getConfig());
}
}
protected String getConfigFileLocation() {
if (configFileLocation != null) {
final String propertyValue = System.getProperty(configFileLocation);
if (propertyValue != null) {
return propertyValue + File.separator + configFileName;
}
}
throw new IllegalStateException("No configuration file defined. System property key: " + configFileLocation);
}
/**
* @inheritDoc
*/
@Override
public T getConfig() {
return config.get();
}
/**
* Returns the Config in a format suitable for revealing to users.
*
* @return A ConfigResponse of the current config. Passwords will be encrypted and the default login wil be removed.
*/
@Override
public ConfigResponse getConfigResponse() {
T config = this.config.get();
config = withoutDefaultLogin(config);
if(config instanceof PasswordsConfig) {
config = ((PasswordsConfig)config).withoutPasswords();
}
return new ConfigResponse<>(config, getConfigFileLocation(), configFileLocation);
}
/**
* Validate the config with the supplied {@link ValidationService}, calls {@link #withoutDefaultLogin(Config)}
* and {@link #withHashedPasswords(Config)} before setting the config, and calls {@link #postUpdate}
* before writing the config to a file.
*
* @param config The new config
* @throws IOException If an error occurs writing out the config file
* @throws ConfigValidationException If the supplied config is invalid.
* @throws Exception if an unspecified error occurs in postUpdate
*/
@Override
public void updateConfig(final T config) throws Exception {
final ValidationResults validationResults = validationService.validateEnabledConfig(config);
if(!validationResults.isValid()) {
throw new ConfigValidationException(validationResults);
}
final T initialConfig = getConfig();
setConfig(config);
try{
postUpdate(config);
} catch (final ConfigException ce) {
setConfig(initialConfig);
throw ce;
}
writeOutConfigFile(this.config.get(), getConfigFileLocation());
}
private void setConfig(final T config) {
final T preMergeConfig = preUpdate(config);
synchronized(updateLock) {
T mergedConfig = preMergeConfig.merge(this.config.get());
mergedConfig = withoutDefaultLogin(mergedConfig);
mergedConfig = withHashedPasswords(mergedConfig);
this.config.set(mergedConfig);
}
}
private void writeOutConfigFile(final T config, final String configFileLocation) throws IOException {
try(Writer writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(configFileLocation), "UTF-8"))){
log.debug("Writing out config file to {}", configFileLocation);
T configToWrite = config;
if(configToWrite instanceof PasswordsConfig) {
configToWrite = ((PasswordsConfig) configToWrite).withEncryptedPasswords(textEncryptor);
}
// TODO: This scales badly and needs rethinking
if(filterProvider != null) {
mapper.writer(filterProvider).writeValue(writer, configToWrite);
}
else {
mapper.writeValue(writer, configToWrite);
}
}
catch(final IOException e) {
log.error("Error writing out config file", e);
throw e;
}
}
/**
* @param systemProperty The name of the system property which stores the location
* of the config file.
*/
public void setConfigFileLocation(final String systemProperty) {
configFileLocation = systemProperty;
}
/**
* @param configFileName The name of the config file
*/
public void setConfigFileName(final String configFileName) {
this.configFileName = configFileName;
}
/**
* @param defaultConfigFile The path to the default config file. This should be a resource on the classpath e.g
* com/example/foo/defaultConfigFile.json
*
*/
public void setDefaultConfigFile(final String defaultConfigFile) {
this.defaultConfigFile = defaultConfigFile;
}
/**
* @param mapper The {@link ObjectMapper} used to perform JSON conversion.
*/
public void setMapper(final ObjectMapper mapper) {
this.mapper = mapper;
}
/**
* If {@link T} is not a {@link PasswordsConfig}, this property need not be set.
* @param textEncryptor The {@link TextEncryptor} used to encrypt passwords.
*/
public void setTextEncryptor(final TextEncryptor textEncryptor) {
this.textEncryptor = textEncryptor;
}
/**
* This property is optional if no filtering is required.
* @param filterProvider The {@link FilterProvider} used to filter the config before writing. This must provide a
* filter called "configurationFilter".
*/
public void setFilterProvider(final FilterProvider filterProvider) {
this.filterProvider = filterProvider;
}
/**
* @param validationService The {@link ValidationService} used to perform validation
*/
public void setValidationService(final ValidationService validationService) {
this.validationService = validationService;
}
/**
* Called after the Config is initialised
* @param config The newly initialised config
* @throws Exception
*/
public abstract void postInitialise(final T config) throws Exception;
/**
* @return The class object representing T.
*/
public abstract Class getConfigClass();
/**
* Returns a configuration object on which no properties have been set.
*
* @return An empty configuration object.
*/
public abstract T getEmptyConfig();
/**
* Generates a default login for a new config file
* @param config The initial config object
* @return A copy of config with a default login, or the same config object if a default login is not required
*/
public abstract T generateDefaultLogin(T config);
/**
* Removes the default login from the configuration object
* @param config The initial config object
* @return A copy of config without a default login, or the same config object if a default login is not required
*/
public abstract T withoutDefaultLogin(T config);
/**
* Hashes any passwords in the configuration object
* @param config The initial config object
* @return A copy of config without any plaintext passwords, or the same config object if there are no passwords
*/
public abstract T withHashedPasswords(T config);
}
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