1. Apache
Celix
Universal
OSGi?
Alexander
Broekhuis
alexander.broekhuis@luminis.eu

2. Introduc<on
• Alexander
Broekhuis
• Started
as
Java
Engineer
• Programming
C
since
2010
• At
Luminis
since
2008
• Small
SoAware
House
• Research
and
innovaEon
oriented
• Involved
in
Open
Source
(Apache)
• Apache
commiKer
since
2010

3. Agenda
• IntroducEon
• History
• OSGi
in
C
• Remote
Services
• Development
• Universal
OSGi
• Status

4. Introduc<on
• OSGi
specificaEon
implemented
in
C
• Adapted
where
needed
• Focussed
on
Embedded
Dynamic
Systems
• Based
on
Apache
Felix
• Remote
Services
• Distributed
Systems
• Interoperability
with
Java

5. History
• Started
in
2010
• Middleware
• Mixed
Java/C
environment
• Based
on
(de-­‐facto)
standards
• Open
Source
• Generic
Middleware
-­‐>
No
core
business
• Benefits
others,
but
also
benefits
FROM
others

6. OSGi
is:
• component
based
framework
• allows
dynamic
assembly
of
components
• Java,
so
independent
of
operaEng
system
OSGi
technology
is
the
dynamic
module
system
for
Java™
OSGi
technology
is
Universal
Middleware.
OSGi
technology
provides
a
service-­‐oriented,
component-­‐based
environment
for
developers
and
offers
standardized
ways
to
manage
the
so@ware
lifecycle.
These
capabiliBes
greatly
increase
the
value
of
a
wide
range
of
computers
and
devices
that
use
the
Java™
plaForm.

7. OSGi
"-)*+(( !"#$%&'&($
"-)*+(($.
)*+,* )*+,* )*+,/-0
,$)1(3$. +&/3$
$-. 4-"-)*+(( )*122"-0 )*12
4-"-)*+(($.
!"#$%&'()*+,'-

8. OSGi
!"#$%& !"#$%&
!"#$%
&"#$%'()*!!
"-)*+(( !"#$%&'&($ +%,'()*!!
"-)*+(($.
)*+,* )*+,* )*+,/-0 !"#$%&'!
("#$%)*+,&-,.!!
,$)1(3$. +&/3$
/0,%(1!"%*&-,.!!
$-. 4-"-)*+(( )*122"-0 )*12
("$%.*23,&-,.!!
4-"-)*+(($.
!"#$%&'!&#!()
*+,-."#$&+/.!!
!"#$%&'()*+,'-

9. OSGi
!"#$%& !"#$%&
!"#$%
&"#$%'()*!!
+%,'()*!!
!"#$%&'!
("#$%)*+,&-,.!!
/0,%(1!"%*&-,.!!
("$%.*23,&-,.!!
!"#$%&'!&#!()
*+,-."#$&+/.!!
!"#$%&'()*+,'-

10. OSGi
!"#$%&"'(")%*+#,
!+-#"
!"#$%& !"#$%&
!"#$%
&"#$%'()*!!
!"#$%&'&$())'*&+,(-./'%0!$1012-)'3"24$1*&+,(-./'5
+%,'()*!!
''''!"#$%&',.%4')-(/-63"24$17.2-18-'&.2-18-9'5
''''''''&.2-18-:/1;%)-1/<1/,%&16<-./1:&$()):;1-=(0169>'2"$$>'
''''''''''''21?'<-./1@0!$699A !"#$%&'!
''''B ("#$%)*+,&-,.!!
''''!"#$%&',.%4')-.!63"24$17.2-18-'&.2-18-9'5 /0,%(1!"%*&-,.!!
''''B
B ("$%.*23,&-,.!!
!"#$%&'!&#!()
*+,-."#$&+/.!!
!"#$%&'()*+,'-

11. Benefits
• Making
products
with
many
variaEons
• Improving
quality
through
re-­‐use
• Speed:
Eme
to
market

12. OSGi
in
C
• Follows
the
OSGi
SpecificaEon
• A
Service
Registry
for
tracking
services
• Bundle
AcEvators
for
registering
services
• Bundle
Lifecycle
for
tracking
Bundle
state
• Structs
instead
of
Interfaces
• Using
funcEon
pointers
to
forward
calls

13. Services
in
C
• Service
• Struct
with
funcEon
pointers
• AcEvator
• start
/
stop
Activator <struct>
• Celix
create
+ start Service
registerService + stop
• bundleContext create
pointer
• registry Celix Component
• etc.. getService depends

14. Services
in
C
-­‐
BundleAc<vator
Java - BundleActivator
@Override
public void start(BundleContext context) throws Exception {
System.out.println("Hello " + m_word);
}
C - BundleActivator
celix_status_t bundleActivator_start(void * userData, BUNDLE_CONTEXT context) {
struct userData * data = (struct userData *) userData;
printf("Hello %sn", data->word);
return CELIX_SUCCESS;
}

15. Services
in
C
-­‐
Service
registra<on
Java - Register service
context.registerService(
ShellService.class.getName(), new ShellServiceImpl(), null);
C - Register service
SHELL_SERVICE shellService = (SHELL_SERVICE) apr_palloc(pool, (sizeof
(*shellService));
shellService->shell = shell;
shellService->getCommands = shell_getCommands;
shellService->getCommandDescription = shell_getCommandDescription;
shellService->getCommandUsage = shell_getCommandUsage;
shellService->getCommandReference = shell_getCommandReference;
shellService->executeCommand = shell_executeCommand;
SERVICE_REGISTRATION registration = NULL;
status = bundleContext_registerService(
context, SHELL_SERVICE_NAME, shellService, NULL, &registration);

16. Dynamic
Assembly
• Dynamic
Loading
• Library
Depends
• Using
dlfcn.h
• dlopen
/
dlclose
<shared object> <shared object>
Celix Initializes Provider Realizes
• dlsym
<struct>
Uses
Provider
Service
Initializes <shared object>
Consumer
Depends

17. Deployment
• Bundling
• Zip
file
with
Shared
Object
• (.so,
.dll,
.dylib,
...)
• Manifest
• Import
/
Export
• RunEme
• Extracted
to
cache

18. Demo
• Paint
ApplicaEon
• From
OSGi
in
AcEon
• Install
/
Start
/
Stop
bundles

19. Remote
Services
• Remote
Service
Admin
• Enterprise
SpecificaEon
• Interoperability
• Protocol
• SOAP?
• REST/JSON
• Hessian

20. Remote
Services
«service»
Server Server Client
imported = "true"
«service»
Server ServerStub ServerProxy Registry
remote = "true"
«track»
Remote Proxy
Publisher Publisher
«service»
«service»
Discovery
Discovery
Service
Service

21. Remote
Services
«service»
Server Server Client
imported = "true"
«service»
Server ServerStub ServerProxy Registry
remote = "true"
«track»
Remote Proxy
Publisher Publisher
«service»
«service»
Stubs Discovery Proxies
Discovery
Service
Service

22. Remote
Services
in
Celix
• REST/JSON
• Basic
implementaEon
working
• Hessian
• Basic
(de)serializaEon
implementaEon
made
• Todo
• Generate
code
for
endpoints
(stubs/proxies)
• Test/Implement
interoperability
with
Java

23. Demo
-­‐
Remote
Services
• Calculator
Example
Service
struct example_service {
example_t example;
celix_status_t (*add)(example_t example,
double a, double b, double *result);
celix_status_t (*sub)(example_t example,
double a, double b, double *result);
celix_status_t (*sqrt)(example_t example,
double a, double *result);
};
• Calculator
Shell
Commands
• add
/
sub
/
sqrt
• Endpoints
using
REST
/
JSON
• Embedded
Mongoose
webserver

24. Demo
-­‐
Remote
Services
• Calculator
Example
Service
struct example_service {
example_t example;
celix_status_t (*add)(example_t example,
double a, double b, double *result);
celix_status_t (*sub)(example_t example,
double a, double b, double *result);
celix_status_t (*sqrt)(example_t example,
double a, double *result);
};
• Calculator
Shell
Commands
• add
/
sub
/
sqrt
• Endpoints
using
REST
/
JSON
• Embedded
Mongoose
webserver

25. PlaJorm
Support
• Apache
Portable
RunEme
• Linux,
Unix,
Windows,
etc
• Memory
pool
• File
handling
• Threads
• No
RealTime/Embedded
• Reuse
APR
API

26. Building
• CMake
• Cross
pladorm
/
MulE
IDE
• Framework
• Standard
library
• Bundle
macros
• Create
bundle
zip
• Add
library
and
resources

27. Universal
OSGi
• RFP-­‐89
• Proposed
to
the
mailing
list
in
2007
• Since
then
remained
silent
• Ongoing
effort
to
pick
up
again
• Supported
Languages
• C++
/
.NET
language
(C#)
/
ECMAScript
• What
about
C?
• Interest
from
Community?

28. Universal
OSGi
-­‐
Celix
• NaEve
port
in
C
• Status
• Based
on
the
R4
SpecificaEon
• Deployable
bundles
• Bundle
lifecycle
• Service
registry
• Framework
API
• Standards
for
IPC
and
communicaEons
• Remote
Services

29. Status
-­‐
Framework
• Dynamic
Loading
of
Libraries
• Service
Registry
for
Querying
and
Registering
• Bundles
with
Manifest
for
Deployment
• Service
Tracker
for
tracking
Services
• Bundle
State
and
Life
Cycle
• Bundle
Cache
for
Storing
State

30. Status
-­‐
Extras
• Shell
ImplementaEon
for
InspecEng
Bundles
• ps/start/stop/install/update/uninstall
commands
• Dependency
Manager
for
Dependencies
• Simple
ImplementaEon
• StaEc
Linked
• Open
Source
at
Apache
• Currently
in
the
Incubator

31. Apache
Celix
• Roadmap
• ...
• Deployment
Admin
• Remote
Services
• ConfiguraEon
Admin
• Event
Admin
• Looking
for
• Users
/
Testers
/
CommiKers

32. Links
• Original
Proposal:
• hKp://wiki.apache.org/incubator/CelixProposal
• Incubator
Mailing
List
Archive:
• hKp://incubator.markmail.org/search/?q=Celix
• IncubaEon
Status:
• hKp://incubator.apache.org/projects/celix.html
• Project
Page:
• hKp://incubator.apache.org/celix/