[libvirt-users] Help needed in simulating libvirt
Hi All, I'm need to simulate libvirt API's say to mock the libvirt API responses. (Actually I need to simulate qemu API's response). Because of my project needs I need to write this simulated libvirt server in Java. I believe the simulated libvirt can be written as java RPC which should capable to receive the client RPC request calls and by dispatcher we can dispatch to the simulated java functions. I searched for .x file to be used for generating server stubs but unfortunately .x files like "remote_protocol.x", "virnetprotocol.x", "qemu_protocol.x" and "lxc_monitor_protocol.x" are not containing any procedure for libvirt API's that exposed. Please let me know which files will have these exposed procedures and how can I use it in java, Also I'm not sure how to implement the ssl layer support for the libvirt server in java. I need to write a java server in such a way that python client should capable to create a connection with uri "qemu+tls://systemip:port?no_tty=1". Also with the created connection object it should able to call the libvirt API's like getCapabilities, etc. Any help and ideas on this will be really helpful. Thanks in Advance, Arun V
On 09/10/2013 12:03 PM, Arun Viswanath wrote:
Hi All, I'm need to simulate libvirt API's say to mock the libvirt API responses. (Actually I need to simulate qemu API's response). Because of my project needs I need to write this simulated libvirt server in Java. I believe the simulated libvirt can be written as java RPC which should capable to receive the client RPC request calls and by dispatcher we can dispatch to the simulated java functions. I searched for .x file to be used for generating server stubs but unfortunately .x files like "remote_protocol.x", "virnetprotocol.x", "qemu_protocol.x" and "lxc_monitor_protocol.x" are not containing any procedure for libvirt API's that exposed. Please let me know which files will have these exposed procedures and how can I use it in java,
Rather than trying to write your own RPC handler, have you considered using the existing libvirt-java bindings and just targetting the test:/// URI connection? This will give you a fairly reliable exposure to the libvirt APIs, without actually needing a working qemu. The .x files implement the driver API; so also does the test driver. Basically, src/libvirt.c is the public API, which then delegates to the appropriate driver based on what URI you connected to; if the URI is remote (as qemu:/// and all other stateful drivers are), then libvirt.so passes it to src/remote/remote_driver.c to be bundled up into RPC calls which mirror the semantics of the public API. If you want to install your own mock driver, it may be easier to build a new URI and implement the same C interface as the test driver (see src/test/test_driver.c) than it is to implement your own RPC parser.
Also I'm not sure how to implement the ssl layer support for the libvirt server in java. I need to write a java server in such a way that python client should capable to create a connection with uri "qemu+tls://systemip:port?no_tty=1". Also with the created connection object it should able to call the libvirt API's like getCapabilities, etc.
Again, instead of trying to write your own RPC server, I'd instead focus on utilizing the existing test:/// driver as your point of mocked calls. As this is mostly development-related, I've set the reply-to to libvir-list (we can drop libvirt-users from the rest of this thread). -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
Hi Eric, Thanks for your response. I like to know how test driver works. In the libvirt.org for test driver it is mentioned as "It can start with a pre-configured default config, or be given a path to an alternate config". Is the config is an xml file where we mentioned some dummy data so that the test driver will return it as response. If yes then where can I find this dummy file? As mentioned earlier my intention is to mock qemu calls. so it test driver works then I'm planning to remove the qemu driver and register "test" driver as "qemu" driver and take the fake data from the config file. Please let me know which are the files I need to look into to register "test" as "qemu" and make its operations to work. Thanks In Advance, Arun V On Wed, Sep 11, 2013 at 12:14 AM, Eric Blake <eblake@redhat.com> wrote:
On 09/10/2013 12:03 PM, Arun Viswanath wrote:
Hi All, I'm need to simulate libvirt API's say to mock the libvirt API responses. (Actually I need to simulate qemu API's response). Because of my project needs I need to write this simulated libvirt server in Java. I believe the simulated libvirt can be written as java RPC which should capable to receive the client RPC request calls and by dispatcher we can dispatch to the simulated java functions. I searched for .x file to be used for generating server stubs but unfortunately .x files like "remote_protocol.x", "virnetprotocol.x", "qemu_protocol.x" and "lxc_monitor_protocol.x" are not containing any procedure for libvirt API's that exposed. Please let me know which files will have these exposed procedures and how can I use it in java,
Rather than trying to write your own RPC handler, have you considered using the existing libvirt-java bindings and just targetting the test:/// URI connection? This will give you a fairly reliable exposure to the libvirt APIs, without actually needing a working qemu.
The .x files implement the driver API; so also does the test driver. Basically, src/libvirt.c is the public API, which then delegates to the appropriate driver based on what URI you connected to; if the URI is remote (as qemu:/// and all other stateful drivers are), then libvirt.so passes it to src/remote/remote_driver.c to be bundled up into RPC calls which mirror the semantics of the public API. If you want to install your own mock driver, it may be easier to build a new URI and implement the same C interface as the test driver (see src/test/test_driver.c) than it is to implement your own RPC parser.
Also I'm not sure how to implement the ssl layer support for the libvirt server in java. I need to write a java server in such a way that python client should capable to create a connection with uri "qemu+tls://systemip:port?no_tty=1". Also with the created connection object it should able to call the libvirt API's like getCapabilities,
etc.
Again, instead of trying to write your own RPC server, I'd instead focus on utilizing the existing test:/// driver as your point of mocked calls.
As this is mostly development-related, I've set the reply-to to libvir-list (we can drop libvirt-users from the rest of this thread).
-- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On Wed, Sep 11, 2013 at 12:50:37PM +0530, Arun Viswanath wrote:
Hi Eric,
Thanks for your response. I like to know how test driver works.
In the libvirt.org for test driver it is mentioned as "It can start with a pre-configured default config, or be given a path to an alternate config". Is the config is an xml file where we mentioned some dummy data so that the test driver will return it as response. If yes then where can I find this dummy file?
As mentioned earlier my intention is to mock qemu calls. so it test driver works then I'm planning to remove the qemu driver and register "test" driver as "qemu" driver and take the fake data from the config file. Please let me know which are the files I need to look into to register "test" as "qemu" and make its operations to work.
The XML file is provided via the URI. For example test:///default uses a built-in config, but you can supply a real path eg test:///home/berrange/testnode.xml Take a look at examples/xml/test/testnode.xml in the libvirt source tree for an example. FYI, the test driver is used very successfully in virt-install and virt-manager for testing their functionality in an automated way, so I can strongly recommend its use, over trying to mock the APIs or wire protocol yourself. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
Hi, Thanks for the response. I've used the URI: "test+ssh://<ipaddress>/default" and the connection is successful and with that connection I issued getCapabilities and its result is attached. I'm not sure how is result xml generated by the files in the /examples folder. Will you please explain how is this xml generated. Also my client is not going to modified. My client is going to connect with the URI "qemu+tls://<host>/system?no_tty=1", so I can't directly use the test driver here so I need to replace the qemu driver with the test driver and give my dummy response. So I need to know how to replace the driver say qemu with test driver and generating my desired output. If the test driver is not going to support me too much then I might want to write new driver. Is there is any reference how to write new driver. Regards, Arun V On Wed, Sep 11, 2013 at 2:23 PM, Daniel P. Berrange <berrange@redhat.com>wrote:
Hi Eric,
Thanks for your response. I like to know how test driver works.
In the libvirt.org for test driver it is mentioned as "It can start with a pre-configured default config, or be given a path to an alternate config". Is the config is an xml file where we mentioned some dummy data so that
On Wed, Sep 11, 2013 at 12:50:37PM +0530, Arun Viswanath wrote: the
test driver will return it as response. If yes then where can I find this dummy file?
As mentioned earlier my intention is to mock qemu calls. so it test driver works then I'm planning to remove the qemu driver and register "test" driver as "qemu" driver and take the fake data from the config file. Please let me know which are the files I need to look into to register "test" as "qemu" and make its operations to work.
The XML file is provided via the URI. For example
test:///default
uses a built-in config, but you can supply a real path eg
test:///home/berrange/testnode.xml
Take a look at examples/xml/test/testnode.xml in the libvirt source tree for an example.
FYI, the test driver is used very successfully in virt-install and virt-manager for testing their functionality in an automated way, so I can strongly recommend its use, over trying to mock the APIs or wire protocol yourself.
Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/:| |: http://libvirt.org -o- http://virt-manager.org:| |: http://autobuild.org -o- http://search.cpan.org/~danberr/:| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc:|
On Wed, Sep 11, 2013 at 04:30:13PM +0530, Arun Viswanath wrote:
Hi,
Thanks for the response.
I've used the URI: "test+ssh://<ipaddress>/default" and the connection is successful and with that connection I issued getCapabilities and its result is attached. I'm not sure how is result xml generated by the files in the /examples folder. Will you please explain how is this xml generated.
You write the XML yourself to describe the initiall characteristics of the host scenario you are trying to simulate. eg the XML file describes what guests you want to pre-create, the capabilities of the host, the storage pools, storage volumes, etc, etc. The examples/xml/test directory shows some illustrations of how todo this.
Also my client is not going to modified. My client is going to connect with the URI "qemu+tls://<host>/system?no_tty=1", so I can't directly use the test driver here so I need to replace the qemu driver with the test driver and give my dummy response. So I need to know how to replace the driver say qemu with test driver and generating my desired output.
Why can't you modify your client. It is pretty reasonable to have the URI be configurable for any libvirt based app, so I don't see why this should be a blocker.
If the test driver is not going to support me too much then I might want to write new driver. Is there is any reference how to write new driver.
I don't see any compelling reason to create a new driver for the scenario you are describing, and would likely reject any patches aiming to do so based in the info you have provided so far. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
Hi Daniel, We are writing a scale test scenario for our client. So for the purpose of scale test with the real code we can't request them to change the URI's, so not too much scope on changing the client. Also we are having some simulated java object of Domain, hypervisor(kvm), etc for which we have to populate the API Call response. Our aim it to simulate one libvirt for more than one KVM hosts so that by some way we will identify to which host particular call come and from that java model we will populate the response. So what I'm trying is to do is to create the initial xml from our java object and then we will start the libvirt test driver. So on the driver I'll try to find the host request and populate the response from the particular xmls. Any good reference or document about how to populate the test response will be really helpful. This is my entire scenario. Any idea or new approach is also really appreciable. Thanks In Advance, Arun V On Wed, Sep 11, 2013 at 4:39 PM, Daniel P. Berrange <berrange@redhat.com>wrote:
On Wed, Sep 11, 2013 at 04:30:13PM +0530, Arun Viswanath wrote:
Hi,
Thanks for the response.
I've used the URI: "test+ssh://<ipaddress>/default" and the connection is successful and with that connection I issued getCapabilities and its result is attached. I'm not sure how is result xml generated by the files in the /examples folder. Will you please explain how is this xml generated.
You write the XML yourself to describe the initiall characteristics of the host scenario you are trying to simulate. eg the XML file describes what guests you want to pre-create, the capabilities of the host, the storage pools, storage volumes, etc, etc. The examples/xml/test directory shows some illustrations of how todo this.
Also my client is not going to modified. My client is going to connect with the URI "qemu+tls://<host>/system?no_tty=1", so I can't directly use the test driver here so I need to replace the qemu driver with the test driver and give my dummy response. So I need to know how to replace the driver say qemu with test driver and generating my desired output.
Why can't you modify your client. It is pretty reasonable to have the URI be configurable for any libvirt based app, so I don't see why this should be a blocker.
If the test driver is not going to support me too much then I might want to write new driver. Is there is any reference how to write new driver.
I don't see any compelling reason to create a new driver for the scenario you are describing, and would likely reject any patches aiming to do so based in the info you have provided so far.
Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/:| |: http://libvirt.org -o- http://virt-manager.org:| |: http://autobuild.org -o- http://search.cpan.org/~danberr/:| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc:|
participants (3)
-
Arun Viswanath -
Daniel P. Berrange -
Eric Blake