The Apache Celix framework is the core of Apache Celix applications and provides supports for deployments of dynamic, extensible modules known as bundles.
An instance of an Apache Celix framework can be created with the celix framework factory or by configuring Apache Celix containers using the add_celix_container
Apache Celix CMake command.
A new instance of an Apache Celix framework can be created using the C/C++ function/method:
celix_frameworkFactory_createFramework
celix::createFramework
When an Apache Celix framework is destroyed it will automatically stop and uninstall all running bundles. For C, an Apache Celix framework needs to be destroyed with the call celix_frameworkFactory_destroyFramework
and for C++ this happens when the framework goes out of scope.
//src/main.c #include <celix_api.h> int main() { //create framework properties celix_properties_t* properties = properties_create(); properties_set(properties, "CELIX_LOGGING_DEFAULT_ACTIVE_LOG_LEVEL", "debug"); //create framework celix_framework_t* fw = celix_frameworkFactory_createFramework(properties); //get framework bundle context and log hello celix_bundle_context_t* fwContext = celix_framework_getFrameworkContext(fw); celix_bundleContext_log(fwContext, CELIX_LOG_LEVEL_INFO, "Hello from framework bundle context"); //destroy framework celix_frameworkFactory_destroyFramework(fw); }
#CMakeLists.txt find_package(Celix REQUIRED) add_executable(create_framework_in_c src/main.c) target_link_libraries(create_framework_in_c PRIVATE Celix::framework)
//src/main.cc #include <celix/FrameworkFactory.h> int main() { //create framework properties celix::Properties properties{}; properties.set("CELIX_LOGGING_DEFAULT_ACTIVE_LOG_LEVEL", "debug"); //create framework std::shared_ptr<celix::Framework> fw = celix::createFramework(properties); //get framework bundle context and log hello std::shared_ptr<celix::BundleContext> ctx = fw->getFrameworkBundleContext(); ctx->logInfo("Hello from framework bundle context"); }
#CMakeLists.txt find_package(Celix REQUIRED) add_executable(create_framework_in_cxx src/main.cc) target_link_libraries(create_framework_in_cxx PRIVATE Celix::framework)
If the Apache Celix framework is the main application, the Apache Celix launcher can be used to create the framework and wait for a framework shutdown.
The Apache Celix launcher also does some additional work:
SIGINT
and SIGTERM
signal.SIGUSR1
and SIGUSR2
signal.curl_global_init
to initialize potential use of curl. Note that the curl_global_init
is not thread safe or protected by something like pthread_once.//src/launcher.c #include <celix_api.h> int main(int argc, char** argv) { return celixLauncher_launchAndWaitForShutdown(argc, argv, NULL); }
#CMakeLists.txt find_package(Celix REQUIRED) add_executable(create_framework_with_celix_launcher src/launcher.c) target_link_libraries(create_framework_with_celix_launcher PRIVATE Celix::framework)
Bundles can be installed and started using the Apache Celix framework bundle context or - when using the Apache Celix launcher - with a “config.properties” file.
Bundles are installed using a path to a zip file. If the path is a relative path, the framework will search for the bundle in the directories configured in the framework property CELIX_BUNDLES_PATH
. The default value of CELIX_BUNDLES_PATH
is “bundles”.
Another option is to use framework properties to configure which bundles to install and start. This can be done by using the CELIX_AUTO_START_0 till CELIX_AUTO_START_6 framework properties. (note that bundles configured in CELIX_AUTO_START_0 are installed and started first). For a more complete overview of possible framework properties see celix_constants.h
If the Apache Celix launcher is used, the framework properties can be provided with a “config.properties” file using the Java Properties File Format.
Framework properties to install and start bundles:
//src/main.c #include <celix_api.h> int main() { //create framework properties celix_properties_t* properties = properties_create(); properties_set(properties, "CELIX_BUNDLES_PATH", "bundles;/opt/alternative/bundles"); //create framework celix_framework_t* fw = celix_frameworkFactory_createFramework(NULL); //get framework bundle context and install a bundle celix_bundle_context_t* fwContext = celix_framework_getFrameworkContext(fw); celix_bundleContext_installBundle(fwContext, "FooBundle.zip", true); //destroy framework celix_frameworkFactory_destroyFramework(fw); }
//src/main.cc #include <celix/FrameworkFactory.h> int main() { //create framework properties celix::Properties properties{}; properties.set("CELIX_BUNDLES_PATH", "bundles;/opt/alternative/bundles"); //create framework std::shared_ptr<celix::Framework> fw = celix::createFramework(properties); //get framework bundle context and install a bundle std::shared_ptr<celix::BundleContext> ctx = fw->getFrameworkBundleContext(); ctx->installBundle("FooBundle.zip"); }
//src/launcher.c #include <celix_api.h> int main(int argc, char** argv) { return celixLauncher_launchAndWaitForShutdown(argc, argv, NULL); }
#CMakeLists.txt find_package(Celix REQUIRED) file(GENERATE OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/config.properties CONTENT " CELIX_BUNDLES_PATH=bundles;/opt/alternative/bundles CELIX_AUTO_START_3=FooBundle.zip ") add_executable(create_framework_with_celix_launcher src/launcher.c) target_link_libraries(create_framework_with_celix_launcher PRIVATE Celix::framework)