OSGi Community Event 2017 Presentation by Emily Jiang [IBM] Eclipse MicroProfile Config defines a Java programming model for microservices. It offers the capability of configuring microservices without repacking the microservices; microservices reacting differently based on the deployment environment; dynamic configuration feeding into the microservices without restarting the microservices. OSGi Config Admin exists for many years and offers an efficient configuration model to OSGi applications. MicroPorfile Config can work well in OSGi applications. It doesn't contradict but instead compliments Config Admin. Come to this session to find out the common and different features between the two technologies, as well as the possibility of integrating Eclipse MicroProfile Config to OSGi applications.

1. © 2017 IBM Corporation
EclipseCon Europe 2017
Eclipse MicroProfile Config and
OSGi Config Admin
Emily Jiang – MicroProfile Development Lead
@emilyfhjiang
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2. © 2017 IBM Corporation
 What are Microservices?
– Small concise service – small piece of SOA
– Easy to maintain
– Easy to release
– Loosely coupled a number of them to form a system
 Microservice best practice
– Configurable
– Fault tolerance
– Monitoring
– Secure
– Working well in the cloud
 How to build it the right way?
– Use Eclipse MicroProfile
2 CDI 1.2

3. © 2017 IBM Corporation
What is Eclipse MicroProfile?
Eclipse MicroProfile is an open-source community specification for Cloud Native Java
microservices
A community of individuals, organizations, and vendors collaborating within an open
source (Eclipse) project to bring microservices to the Enterprise Java community
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Community - individuals, organizations, vendors
And Growing ...
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 Why Eclipse MicroProfile?
– Microservice portable among application servers
– No vendor locking unlike Spring
– Fast innovating
– Frequent release cycle
5 CDI 1.2

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Accelerating Adoption of Microservices
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Time
8 ?
MicroProfile 1.0
CDI 1.2
JAX-RS 2.0
JSON-P 1.0
MicroProfile 1.2MicroProfile 1.1
MicroProfile 1.0
MP Config 1.0 MicroProfile 2.0 MicroProfile 2.1 MicroProfile 2.2
MicroProfile 1.3 MicroProfile 1.x

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MicroProfile 1.0 (Fall 2016)
jaxrs-2.0
cdi-1.2
jsonp-1.0
MicroProfile 1.1 (August
2017)
microProfile-1.0
mpConfig-1.0 MicroProfile 1.2 (Sept 2017)
microProfile-1.1
mpConfig-1.1
mpFaultTolerance-1.0
mpHealth-1.0
mpMetrics-1.0
mpJwt-1.0
MicroProfile 1.3 (???)
MicroProfile 1.2
mpTracing-1.0
mpOpenApi-1.0
MicroProfile 2.0 (1Q 2018?)
MicroProfile 1.3
jaxrs-2.1 // Java EE 8
cdi-2.0 // Java EE 8
jsonp-1.1 // Java EE 8
jsonb-1.0 // Java EE 8
2017
2018
Aug Sept

8. © 2017 IBM Corporation
Eclipse MicroProfile 1.2 (Sep, 2017)
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MicroProfile 1.2
= Updated
= No change from last release
JAX-RS 2.0JSON-P 1.0CDI 1.2
Config 1.1
Fault
Tolerance
1.0
JWT
Propagation
1.0
Health
Check 1.0
Metrics 1.0
= New

9. © 2017 IBM Corporation
http://microprofile.io/
MicroProfile adds new enterprise Java capabilities for microservices
Config Fault Tolerance Health Check Health Metrics JWT
externalize
configuration to
improve portability
build robust behavior
to cope with
unexpected failures
ensure services are
running
understand the
interactions between
services while running
resolve problems in
complex distributed
systems
New in Eclipse MicroProfile Release 1.2: https://projects.eclipse.org/projects/technology.microprofile/releases/1.2
Robust Microservices

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MicroProfile Config 1.1
 Why?
– Configure Microservice without repacking the application
 How?
– Properties from the built-in configure sources with default config ordinals:
• META-INFmicroprofile-config.properties (default ordinal = 100)
• System properties (default ordinal = 400)
• Environment variables (default ordinal = 300)
– Provide custom configure sources with a priority
– Provide custom converters with a priority
– Access properties
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Provide a config source
 Step 1: Create a class that implements org.eclipse.microprofile.config.spi.ConfigSource
 Step 2: Register the class using service loader pattern
– Create a file under META-INFserviceorg.eclipse.microprofile.config.spi.ConfigSource
– Inside the file: put the fully qualified config source implementation class name
 Step 2: Alternatively, directly call SPI to add a config source to a builder and then build a
config
– ConfigProviderResolver.getBuilder() .withSources(ConfigSource…
configSources).build()
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Provide a Converter
 The config properties are all specified in strings in config sources.
 In order to get a ultimate value other than the built-in types, a converter is needed.
 Step 1: Create a class that implements org.eclipse.microprofile.config.spi.Converter
 Step 2: Register the class using service loader pattern.
– Create a file under META-INFserviceorg.eclipse.microprofile.config.spi.Converter
– Inside the file: put the fully qualified config converter implementation class name
 Step 2: alternatively, directly call SPI to add a config source to a builder and then build a config
– ConfigProviderResolver.getBuilder() .withConfigSources(…).withConverters(Converter… converter).build()
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public interface Converter<T> {
/**
* Configure the string value to a specified type
* @param value the string representation of a property value.
* @return the converted value or null
*
* @throws IllegalArgumentException if the value cannot be converted to the
specified type.
*/
T convert(String value);
}

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Look up properties
– Access configuration via
• Programmatically lookup
Config config = ConfigProvider.getConfig();
config.getValue(“myProp”, String.class);
• Via CDI Injection
@Inject @ConfigProperty(name="my.string.property") String myPropV;
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MicroProfile Config
 Static Config
 Dynamic Config
@Inject
@ConfigProperty(name="myStaticProp"
)
private String staticProp;
@Inject
@ConfigProperty(name="myDynamicProp
")
private Provider<String>
dynamicProp;
microprofile-config.properties
myStaticProp=defaultSValue
myDynamicProp=defaultDValue
Java Options
-DmyStaticProp=customSValue
-DmyDynamicProp=customDValue
overrides

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 OSGi r7 has Config Admin
Config Admin
PID Configuration
com.acme Name=Bob
Age= 18
12.1 Name = Andy
Age = 22
pid=com.acme

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Why bother to support MicroProfile Config in OSGi?
o Future aspiration goal
• Application using CDI, JAX-RS can run unchanged in OSGi, MicroProfile 1.0
• Applications using MicroProfile programming model including Config can run
unchanged in OSGi

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 How to support MicroProfile Config in OSGi?
o MP Config Implementation bundle registers the ConfigProvider service
o MP Config Implementation bundle registers CDI extension to register Config bean, a
producer to produce config properties with the qualifier ConfigProperty
o Depend on CDI in OSGi specification
app bundle MP Config
Impl
ConfigProvider
CDI beans

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 Create an ecosystem with MicroProfile Config and Config Admin
o Config Admin offer maps containing properties
o Config Admin can be treated as a config source in MicroProfile Config with the
specified the config_ordinal (a normal key value, 500 if not exists).

19. © 2017 IBM Corporation
 OSGi r7 supports Converters
o Not quite the same as the MicroProfile Config Conveter
o Use converter adapter to convert OSGi converters to be used as MicroProfile
converters
o Call into OSGi converter service to do the conversion

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 Resources
– http://microprofile.io/
– https://openliberty.io/
– https://www.eclipse.org/community/eclipse_newsletter/2017/september/

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Thank you
Special Thanks to BJ Hargrave for your contributions
towards the integration part!