8.9. dev:wait-for-service, wait-for-service

Abstract

wait for the specified OSGi service

Synopsis

dev:wait-for-service [ --help ] [[ -t ] | [ --timeout ]timeout] [[ -e ] | [ --exception ]] { serviceClassOrFilter }

Description

This command is useful when you are developing a console script and you want to wait for a specific OSGi service to start up, before proceeding with the execution of the script.
For example, the various command sets installed in the console (shell:*, admin:*, features:*, and so on) are represented by OSGi services of type, org.apache.karaf.shell.console.SubShell. If you want to check that a sub-shell service is available, you could enter the following console command:
karaf@root> dev:wait-for-service -t 1000 org.apache.karaf.shell.console.SubShell
true
This form of the command is not very useful in this case, because there are many different instances of the SubShell service installed in the container. To be more specific, you can define an LDAP filter, which specifies one or more service property values. For example, you can wait specifically for the osgi sub-shell service by entering a command like the following:
karaf@root> dev:wait-for-service -t 1000 &(objectClass=org.apache.karaf.shell.console.SubShell)(name=osgi)
true

Arguments

Table 8.9, “dev:wait-for-service Arguments” describes the commands arguments.

Table 8.9. dev:wait-for-service Arguments

ArgumentInterpretation
--helpDisplays the online help for this command
-t, --timeoutTimeout (specified in milliseconds: negative to not wait at all, zero to wait forever). Default is forever.
-e, --exceptionThrow an exception if the wait command times out (the service is not found). Default is false.
serviceClassOrFilterSpecifies the OSGi service either by the service's class name or by an LDAP-style filter (which is applied to the OSGi service's properties).