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

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information purposes only, and may not be incorporated into any contract. It is not a
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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

Config JSR and Tamaya

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