Configuration for Java EE: Config JSR and Tamaya

Copyright © 2016, Oracle and/or its affiliates. All rights reserved.
Configuration for Java EE
Dmitry Kornilov
@m0mus
Werner Keil
@wernerkeil
November 16, 2016
Config JSR and Tamaya

Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
2

Copyright © 2016, Oracle and/or its affiliates. All rights reserved. 3
Dmitry Kornilov
• Software Developer @ Oracle
• JSON-B (JSR-367) spec lead
• JSON-P (JSR-374) spec lead
• Outstanding Spec Lead 2016
• EclipseLink project committer

Werner Keil
• Consultant – Coach
• Creative Cosmopolitan
• Open Source Evangelist
• Software Architect
• Spec Lead – JSR363
• Individual JCP Executive Committee
Member

Program Agenda
Introduction
Problem Definition
JSR Proposal & Features
Tamaya
Q & A
1
2
3
4
5
5

Introduction
6

Oracle Java EE 8 Survey 2014
Confidential – Oracle

DZone and Java EE Guardians Survey Results

Java EE 7
Connector JAXBJSP Debugging
Managed BeansJSPConcurrency EE Interceptors JAX-WS WebSocket
Bean Validation JASPIC ServletJMS JTADeployment
Batch JACCDependency
Injection JAXR JSTL Management
CDI EJB JAX-RPC Web ServicesJSF Java Persistence
JSON-PCommon
Annotations EL JAX-RS Web Services
MetadataJavaMail
CDI
JSON-P
Security
Bean Validation
JSF
JAX-RS
JSP
Servlet
Health CheckConfiguration
Java EE 8 (Revised Proposal, 2016)
JSON-B

Problem Definition
10

What is Configuration?
11
Application server setup?
Runtime parameters?
Deployment descriptors?
Parameters of used frameworks?
Deployment scripts? Used resources?

Problems
• Lack of standard configuration API
• Configuring multiple instances
• Deploying on different environments
• Change configuration without
redeployment
• Configuration of decoupled
microservices
12

Problems
redeployment
microservices
13

Problems
redeployment
microservices
14

Problems
redeployment
microservices
15

Problems
redeployment
microservices
16

JSR Proposal
17

Configuration Definition
• Application centric
• Not modifiable by application
• Consists of key/value pairs
• Keys and values are strings
• Flat structure
18

Java EE Configuration
• Unified API
• Externalized configuration
• Support of multiple configuration sources
– Properties, xml and json formats support out of the box
• Layering and overrides
• Optional configuration descriptor
• Dynamic configuration
• Integration with other Java EE frameworks
19

Java EE Configuration
• Unified API
• Externalized configuration
• Support of multiple configuration sources
– Properties, xml and json formats support out of the box
• Layering and overrides
20
Java EE 8
• Optional configuration descriptor
• Dynamic configuration
• Integration with other Java EE frameworks
Java EE 9

JSR Features (Java EE 8)
21

API
22
a=JavaOne
b=9
c=2016
Config config = ConfigProvider.getConfig();
// Returns "JavaOne"
String a = config.getProperty("a");
// Returns string "9"
String b = config.getProperty("b");
// Returns string "default"
String defaultValue = config.getProperty("not.exist", "default");
// Returns number 2016
Long c = config.getProperty("c", Long.class);

Converters
23
• Type safe access to values
• Built-in converters for:
– Primitive Wrappers
– BigDecimal, BigInteger, URL, URI
– Date, Calendar
– java.time.*
public interface Converter<Target> {
Target convert(String value, Config c);
}
public class FooConverter
implements Converter<Foo> {
public Foo convert(String value, Config c) {
...
}
}
Config cfg = ConfigProvider.builder()
.withConverters(new FooConverter())
.build();
Foo foo = cfg.getProperty("foo", Foo.class);

Configuration Sources
24
• Multiple configuration sources
• Supported configuration sources:
– System properties
– Runtime parameters
– File (Properties, xml, json)
– Resource on a web server
• Pluggable architecture
– Custom sources (like DB)
• Configuration sources are ordered
Java EE
Config
XML JSONprop
DBweb
Application

Default Configuration Sources
25
Java EE Config
• System properties (ordinal=400)
• Environment properties (ordinal=300)
• /META-INF/config.properties (ordinal=100)
• /META-INF/config.xml (ordinal=100)
• /META-INF/config.json (ordinal=100)

Defining Configuration Sources
26
• Using config.sources runtime parameter
• Using API
• Using config-sources.xml file
java –jar my.jar –Dconfig.source=http://shared/global.xml,/conf/my.json
Config config = ConfigProvider.builder()
.addSource(new WebSource("http://shared:8080/global.xml"), 200)
.addSource(new FileSource("/conf/my.json"), 100)
.addSource(new MyCustomSource())
.build();

config-sources.xml
27
• File with defined schema using to define configuration sources and their
metadata
• Default location /META-INF/config-sources.xml
• Can be placed outside of the application package
• Define using runtime parameter
• Define using API
java –jar my.jar –Dconfig.sources=http://sharedhost/config-sources.xml
Config c = ConfigProvider.builder()
.withSources("/cfg/config-sources.xml")
.build();

Sample config-sources.xml
28
Simple
With ordinals
<config-sources>
<source>http://shared:8080/config.xml</source>
<source>/cfg/myconf.json</source>
</config-sources>
<config-sources>
<source ordinal="500">http://shared:8080/config.xml</source>
<source ordinal="450">/cfg/myconf.json</source>
</config-sources>

Sample config-sources.xml
29
Custom
<config-sources>
<source>http://shared:8080/config.xml</source>
<source type="com.oracle.config.CloudConfig">
<user>user</user>
<password>secret</password>
</source>
</config-sources>

JSR Features (Java EE 9)
30

Integration With Other Java EE Frameworks
• Read configuration from
Java EE Config
• Store configuration as part of
whole application configuration
• Use standard API
31
Java EE
Config
Application
Configuration
Application
JPA
Configuration
JAX-RS
Configuration

Configuration Descriptor
32
• File with defined format
• Defines all configurable properties
and metadata
• Optional
• It’s not XML-Schema!
<config-descriptor>
<property name="a"/>
<property name="b" default=”valueB"/>
<property name="c" mutable="false"/>
<property name="d"/>
</config-descriptor>

Dynamic Configuration
33
• Polling framework
• Expressions
• Property Resolvers
• Configuration Context

Polling
34
// Defining polling using API
.withSource(new FileSource("/cfg/config.xml"), 200, Duration.ofSeconds(30))
.withSource(new WebSource("http://shared/config.xml"), 100, Duration.ofMinutes(1))
.build();

Polling
35
// Defining polling using API
.withSource(new FileSource("/cfg/config.xml"), 200, Duration.ofSeconds(30))
.withSource(new WebSource("http://shared/config.xml"), 100, Duration.ofMinutes(1))
.build();
Ordinal Refresh IntervalLocation

Polling
36
<config-sources refresh-rate="300000">
<source ordinal="200" refresh-rate="30000">/cfg/config.xml</source>
<source ordinal="100" refresh-rate="60000">http://shared/config.xml</source>
</config-sources>

Polling
37
<config-sources refresh-rate="300000">
<source ordinal="200" refresh-rate="30000">/cfg/config.xml</source>
<source ordinal="100" refresh-rate="60000">http://shared/config.xml</source>
</config-sources>
Sources list
refresh interval
(5 min)
Source 1 refresh
interval (30 sec) Source 2 refresh
interval (1 min)

Expressions
38
• EL like expressions evaluated at runtime to a property value
• Property substitution
• Conditional configuration sources
foo=${some.other.value}
bar=${foo + 10}
baz=${foo * bar}
<config-sources>
<source>//cfg/config.properties</source>
<source enabled=”${app==‘ios’}”>
//cfg/cust_ios.properties
</source>
</config-sources>

Property Resolvers
39
• Flexible mechanism allowing
executing user code in configuration
expressions
• Can be used to inject cloud
resources
rating.service.url=${eureka:rating.url}
cust.db=${cloud:cust.db}
<config-sources>
<resolvers>
<resolver name=”cloud”>
<class>com.example.CloudResolver</class>
<username>user</username>
<password>secret</password>
</resolver>
</resolvers>

</config-sources>

Configuration Context
40
• Allows setting application variables which can be used in configuration
expressions
• Example: geographical zone, application type, etc.
<config-sources>
<source>/cfg/config.properties</source>
<source enabled=”${app==‘ios’}”>cust_ios.properties</source>
</config-sources>
Config config = ConfigProvider.getConfig();
ConfigContext context = ConfigContext.builder().addProperty("app", "ios").build();
Long prop = config.getPropertyWithContext("prop", context);

Tamaya
41

• Configuration = ordered list of PropertySources
• Properties found are combined using a
CombinationPolicy
• Raw properties are filtered by PropertyFilter
• For typed access PropertyConverters
have to do work
• Extensions add more features
• Component Lifecycle is controlled by the
ServiceContextManager
ConfigurationContext
PropertyFilters
PropertySource
PropertySource
PropertySource
PropertySource
Configuration
CombinationPolicy
PropertyProviders
<provides>
PropertyConverter
42
Apache Tamaya in 120 seconds...

Requirements
• Developer‘s Perspective
• Architectural/Design Requirements
• Operational Aspects
• Other Aspects

Developer‘s Requirements
• Easy to use.
• Developers want defaults.
• Developers don‘t care about the runtime (for configuration only).
• Developers are the ultimate source of truth
• Type Safety

Architectural/Design Requirements
• Decouple code that consumes configuration from
– Backends Used
– Storage Format
– Distribution
– Lifecycle and versioning
– Security Aspects

Operational's Requirements
• Enable Transparency:
– What configuration is available ?
– What are the current values and which sources provided the value ?
– Documentation
• Manageable:
– Configuration changes without redeployment or restart.
– Solution must integrate with existing environment

Other Aspects
• Support Access Constraints and Views
• No accidental logging of secrets
• Dynamic changes
• Configuration Validation

API Requirements
• Leverage existing functionality where useful
• Only one uniform API for access on all platforms!
• Defaults provided by developer during development
(no interaction with operations or external dependencies)

Existing Mechanisms
• Environment Properties
• System Properties
• CLI arguments
• Properties, xml-Properties

Dependencies - API & Core
<dependency>
<groupId>org.apache.tamaya</groupId>
<artifactId>tamaya-api</artifactId>
<version>0.3-incubating-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.apache.tamaya</groupId>
<artifactId>tamaya-core</artifactId>
</dependency>

Programmatic API
Configuration config = ConfigurationProvider.getConfiguration();
// single property access
String name = config.getOrDefault("name", "John");
int ChildNum = config.get("childNum", int.class);
// Multi property access
Map<String,String> properties = config.getProperties();
// Templates (provided by extension)
MyConfig config = ConfigurationInjection.getConfigurationInjector()
.getConfig(MyConfig.class);

Dependencies – Injection SE
<dependency>
<groupId>org.apache.tamaya.ext</groupId>
<artifactId>tamaya-injection-api</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tamaya.ext</groupId>
<artifactId>tamaya-injection</artifactId>
</dependency>

Dependencies – Injection SE
@Config(value="admin.server", defaultValue="127.0.0.1")
private String server;
@Config(value="admin.port", defaultValue="8080")
private int port;
@Config(value="admin.connections")
private int connections = 5;
@Config("address")
private Address address; MyTenant t = new MyTenant();
ConfigurationInjection
.getConfigurationInjector()
.configure(t);

Configuration Backends
• Support existing mechanisms OOTB
• Provide a simple SPI for (multiple) property sources
• Define a mechanism to prioritize different property sources
• Allow different strategies to combine values
• Support Filtering
• Support Type Conversion

PropertySource
public interface PropertySource {
PropertyValue get(String key);
Map<String, String> getProperties();
boolean isScannable();
String getName();
int getOrdinal();
}
public final class PropertyValue{
public String getKey();
public String getValue();
public String get(String key);
public Map<String, String> getConfigEntries();
...
}

Predefined Property Sources
• System & Environment Properties
• (CLI Arguments)
• Files
– ${configDir}/*.properties
• Classpath Resources
– /META-INF/javaconfiguration.properties

Property Sources
• Mostly map to exact one file, resource or backend
• Have a unique name
• Must be thread safe
• Can be dynamic
• Provide an ordinal
• Can be scannable

PropertySource - Example
public class MyPropertySource extends BasePropertySource {
private Map<String, String> props = new HashMap<>();
public SimplePropertySource() throws IOException {
URL url = getClass().getClassLoader().getResource(
"/META-INF/myFancyConfig.xml");
// read config properties into props
...
}
@Override
public String getName() { return "/META-INF/myFancyConfig.xml"; };
@Override
public Map<String, String> getProperties() { return props; }
}

PropertySource - Registration
• By default, register it using the java.util.ServiceLoader
– → /META-INF/services/org.apache.tamaya.spi.PropertySource
– MyPropertySource

PropertySource Provider
• Allow dynamic registration of multiple property sources
• E.g. all files found in a config directory
• Are evaluated once and then discarded
• Are also registered using the ServiceLoader.
public interface PropertySourceProvider{
public Collection<PropertySource> getPropertySources();
}

More SPI artifacts
• Filters for filtering values evaluated (remove, map, change)
• Converters for converting String values to non-String types
• A ValueCombinationPolicy
– determines how values evaluated are combined to a final value
(defaults to overriding)

Q & A
62

Configuration for Java EE: Config JSR and Tamaya

More Related Content

What's hot

Similar to Configuration for Java EE: Config JSR and Tamaya

More from Dmitry Kornilov

Recently uploaded

Configuration for Java EE: Config JSR and Tamaya