com.helger.config.ConfigFactory Maven / Gradle / Ivy
/*
* Copyright (C) 2014-2024 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* 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.
*/
package com.helger.config;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.helger.commons.io.file.FilenameHelper;
import com.helger.commons.io.resource.ClassPathResource;
import com.helger.commons.io.resource.FileSystemResource;
import com.helger.commons.io.resource.URLResource;
import com.helger.commons.io.resourceprovider.ClassPathResourceProvider;
import com.helger.commons.io.resourceprovider.FileSystemResourceProvider;
import com.helger.commons.io.resourceprovider.ReadableResourceProviderChain;
import com.helger.commons.lang.ClassLoaderHelper;
import com.helger.commons.string.StringHelper;
import com.helger.commons.url.URLHelper;
import com.helger.config.source.EConfigSourceType;
import com.helger.config.source.MultiConfigurationValueProvider;
import com.helger.config.source.envvar.ConfigurationSourceEnvVar;
import com.helger.config.source.res.ConfigurationSourceJson;
import com.helger.config.source.res.ConfigurationSourceProperties;
import com.helger.config.source.res.EConfigSourceResourceType;
import com.helger.config.source.sysprop.ConfigurationSourceSystemProperty;
/**
* Factory for creating {@link IConfig} objects.
*
* @author Philip Helger
*/
@Immutable
public final class ConfigFactory
{
public static final String PRIVATE_APPLICATION_JSON_NAME = "private-application.json";
public static final int PRIVATE_APPLICATION_JSON_PRIORITY = EConfigSourceType.RESOURCE.getDefaultPriority () - 5;
public static final String PRIVATE_APPLICATION_PROPERTIES_NAME = "private-application.properties";
public static final int PRIVATE_APPLICATION_PROPERTIES_PRIORITY = EConfigSourceType.RESOURCE.getDefaultPriority () -
10;
public static final String APPLICATION_JSON_NAME = "application.json";
public static final int APPLICATION_JSON_PRIORITY = EConfigSourceType.RESOURCE.getDefaultPriority () - 15;
public static final String APPLICATION_PROPERTIES_NAME = "application.properties";
public static final int APPLICATION_PROPERTIES_PRIORITY = EConfigSourceType.RESOURCE.getDefaultPriority () - 20;
public static final String REFERENCE_PROPERTIES_NAME = "reference.properties";
public static final int REFERENCE_PROPERTIES_PRIORITY = 1;
private static final Logger LOGGER = LoggerFactory.getLogger (ConfigFactory.class);
private static final EConfigSourceResourceType FALLBACK_SOURCE_TYPE = EConfigSourceResourceType.PROPERTIES;
/**
* Use this configuration internally to resolve the properties used for the
* default instance. The "system only" resolver considers system properties
* and environment variables only.
* Initialization order is critical - this one must be first.
*/
private static final IConfig SYSTEM_ONLY = Config.create (createValueProviderSystemOnly ());
private static final IConfig DEFAULT_INSTANCE = Config.create (createDefaultValueProvider ());
static
{
final int nResourceBased = DEFAULT_INSTANCE.getResourceBasedConfigurationValueProviderCount ();
if (nResourceBased == 0)
{
// Small consistency check
LOGGER.info ("The default Config instance is solely based on system properties and environment variables. No configuration resources were found.");
}
}
/**
* Create a configuration value provider, with the following configuration
* sources:
*
* - Query system properties - names are takes "as are" - priority 400.
* - Environment variables. All non-alphanumeric characters are replaced
* with underscores. So e.g. the property 'a.b' resolves to the environment
* variable "A_B" - priority 300
*
* Usually this is not what you are looking for but
* {@link #createDefaultValueProvider()}
*
* @return A new value provider. Never null.
* @since 9.4.5
* @see #createDefaultValueProvider()
*/
@Nonnull
public static MultiConfigurationValueProvider createValueProviderSystemOnly ()
{
final MultiConfigurationValueProvider aMCSVP = new MultiConfigurationValueProvider ();
// Prio 400
aMCSVP.addConfigurationSource (new ConfigurationSourceSystemProperty ());
// Prio 300
aMCSVP.addConfigurationSource (new ConfigurationSourceEnvVar ());
return aMCSVP;
}
/**
* @return A new instance of {@link ReadableResourceProviderChain} used to
* resolve resource based configuration items.
* @since 9.4.8
*/
@Nonnull
public static ReadableResourceProviderChain createDefaultResourceProviderChain ()
{
return new ReadableResourceProviderChain (new FileSystemResourceProvider ().setCanReadRelativePaths (true),
new ClassPathResourceProvider ());
}
/**
* Create a configuration value provider, with the following configuration
* sources:
*
* - Query system properties - names are takes "as are" - priority 400.
* - Environment variables. All non-alphanumeric characters are replaced
* with underscores. So e.g. the property 'a.b' resolves to the environment
* variable "A_B" - priority 300
* - If a system property
config.resource exists and it points
* to an existing classpath resource, the first one matching is used -
* priority 200 or determined by system property
* config.resource.priority (since v9.4.5)
* - If a system property
config.resources (note the trailing
* "s") exists and it points to an existing classpath resource, all matching
* ones are used - priority 200 or determined by system property
* config.resources.priority (also see the "s") (since
* v9.4.5)
* - If a system property
config.file exists and it points to
* an existing file, it is used - priority 200 or determined by system
* property config.file.priority (since v9.4.5)
* - If a system property
config.url exists and it points to an
* existing URL, it is used - priority 200 or determined by system property
* config.url.priority (since v9.4.5)
* - A file or classpath entry with the name
*
private-application.json - priority 195
* - A file or classpath entry with the name
*
private-application.properties - priority 190
* - Than all instances of
application.json are looked up on
* the classpath (only!). All of them share priority 185
* - Than all instances of
application.properties are looked up
* on the classpath (only!). All of them share priority 180
* - Than all instances of
reference.properties are looked up
* on the classpath (only!). All of them share priority 1
*
*
* Note: the default configuration does NOT contain any custom
* configuration files.
*
*
* Note: JSON and Properties files are expected to be UTF-8 encoded.
*
*
* @return A new value provider. Never null.
*/
@Nonnull
public static MultiConfigurationValueProvider createDefaultValueProvider ()
{
final MultiConfigurationValueProvider aMCSVP = new MultiConfigurationValueProvider ();
// Prio 400
aMCSVP.addConfigurationSource (new ConfigurationSourceSystemProperty ());
// Prio 300
aMCSVP.addConfigurationSource (new ConfigurationSourceEnvVar ());
final int nResourceDefaultPrio = EConfigSourceType.RESOURCE.getDefaultPriority ();
final ClassLoader aCL = ClassLoaderHelper.getDefaultClassLoader ();
// Prio 200 - external files
{
// Load one only
final String sConfigResource = SYSTEM_ONLY.getAsString ("config.resource");
if (StringHelper.hasText (sConfigResource))
{
final EConfigSourceResourceType eResType = EConfigSourceResourceType.getFromExtensionOrDefault (FilenameHelper.getExtension (sConfigResource),
FALLBACK_SOURCE_TYPE);
final ClassPathResource aRes = new ClassPathResource (sConfigResource);
if (aRes.exists ())
{
// Take priority from system property
final int nPriority = SYSTEM_ONLY.getAsInt ("config.resource.priority", nResourceDefaultPrio);
aMCSVP.addConfigurationSource (eResType.createConfigurationSource (aRes), nPriority);
}
}
}
{
// Load all
final String sConfigResources = SYSTEM_ONLY.getAsString ("config.resources");
if (StringHelper.hasText (sConfigResources))
{
// Take priority from system property
final int nPriority = SYSTEM_ONLY.getAsInt ("config.resources.priority", nResourceDefaultPrio);
final EConfigSourceResourceType eResType = EConfigSourceResourceType.getFromExtensionOrDefault (FilenameHelper.getExtension (sConfigResources),
FALLBACK_SOURCE_TYPE);
// Classpath only
aMCSVP.addConfigurationSource (MultiConfigurationValueProvider.createForClassPath (aCL,
sConfigResources,
aURL -> eResType.createConfigurationSource (new URLResource (aURL))),
nPriority);
}
}
{
final String sConfigFile = SYSTEM_ONLY.getAsString ("config.file");
if (StringHelper.hasText (sConfigFile))
{
final EConfigSourceResourceType eResType = EConfigSourceResourceType.getFromExtensionOrDefault (FilenameHelper.getExtension (sConfigFile),
FALLBACK_SOURCE_TYPE);
final FileSystemResource aRes = new FileSystemResource (sConfigFile);
if (aRes.exists ())
{
// Take priority from system property
final int nPriority = SYSTEM_ONLY.getAsInt ("config.file.priority", nResourceDefaultPrio);
aMCSVP.addConfigurationSource (eResType.createConfigurationSource (aRes), nPriority);
}
}
}
{
final String sConfigURL = SYSTEM_ONLY.getAsString ("config.url");
if (StringHelper.hasText (sConfigURL))
{
final EConfigSourceResourceType eResType = EConfigSourceResourceType.getFromExtensionOrDefault (FilenameHelper.getExtension (sConfigURL),
FALLBACK_SOURCE_TYPE);
final URL aURL = URLHelper.getAsURL (sConfigURL);
if (aURL != null)
{
final URLResource aRes = new URLResource (aURL);
if (aRes.exists ())
{
// Take priority from system property
final int nPriority = SYSTEM_ONLY.getAsInt ("config.url.priority", nResourceDefaultPrio);
aMCSVP.addConfigurationSource (eResType.createConfigurationSource (aRes), nPriority);
}
}
}
}
// Prio 195, incl. files
aMCSVP.addConfigurationSource (MultiConfigurationValueProvider.createForAllOccurrances (aCL,
PRIVATE_APPLICATION_JSON_NAME,
aURL -> new ConfigurationSourceJson (PRIVATE_APPLICATION_JSON_PRIORITY,
new URLResource (aURL),
StandardCharsets.UTF_8),
true),
PRIVATE_APPLICATION_JSON_PRIORITY);
// Prio 190, incl. files
aMCSVP.addConfigurationSource (MultiConfigurationValueProvider.createForAllOccurrances (aCL,
PRIVATE_APPLICATION_PROPERTIES_NAME,
aURL -> new ConfigurationSourceProperties (PRIVATE_APPLICATION_PROPERTIES_PRIORITY,
new URLResource (aURL),
StandardCharsets.UTF_8),
true),
PRIVATE_APPLICATION_PROPERTIES_PRIORITY);
// Prio 185, incl. files
aMCSVP.addConfigurationSource (MultiConfigurationValueProvider.createForAllOccurrances (aCL,
APPLICATION_JSON_NAME,
aURL -> new ConfigurationSourceJson (APPLICATION_JSON_PRIORITY,
new URLResource (aURL),
StandardCharsets.UTF_8),
true),
APPLICATION_JSON_PRIORITY);
// Prio 180, incl. files
aMCSVP.addConfigurationSource (MultiConfigurationValueProvider.createForAllOccurrances (aCL,
APPLICATION_PROPERTIES_NAME,
aURL -> new ConfigurationSourceProperties (APPLICATION_PROPERTIES_PRIORITY,
new URLResource (aURL),
StandardCharsets.UTF_8),
true),
APPLICATION_PROPERTIES_PRIORITY);
// Prio 1
aMCSVP.addConfigurationSource (MultiConfigurationValueProvider.createForAllOccurrances (aCL,
REFERENCE_PROPERTIES_NAME,
aURL -> new ConfigurationSourceProperties (REFERENCE_PROPERTIES_PRIORITY,
new URLResource (aURL),
StandardCharsets.UTF_8),
true),
REFERENCE_PROPERTIES_PRIORITY);
return aMCSVP;
}
private ConfigFactory ()
{}
/**
* Get a special {@link IConfig} instance that is only intended to be used to
* setup other config instances. Usually you are looking for
* {@link #getDefaultConfig()}.
*
* @return The system configuration to be used. Never null.
* @see #getDefaultConfig()
* @since 9.4.5
*/
@Nonnull
public static IConfig getSystemConfig ()
{
return SYSTEM_ONLY;
}
/**
* Get the default {@link IConfig} instance. This call has linear effort. See
* {@link #createDefaultValueProvider()} on the resolutions that are
* attempted.
*
* @return The default configuration to be used. Never null.
* @see #createDefaultValueProvider()
*/
@Nonnull
public static IConfig getDefaultConfig ()
{
return DEFAULT_INSTANCE;
}
}
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