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< html xmlns = "http://www.w3.org/1999/xhtml" > < head > < meta http-equiv = "Content-Type" content = "text/html; charset=ISO-8859-1" / > < link rel = "stylesheet" type = "text/css" href = "libvirt.css" / > < link rel = "SHORTCUT ICON" href = "/32favicon.png" / > < title > Bindings for other languages< / title > < / head > < body > < div id = "container" > < div id = "intro" > < div id = "adjustments" > < / div > < div id = "pageHeader" > < / div > < div id = "content2" > < h1 class = "style1" > Bindings for other languages< / h1 > < p > Libvirt comes with bindings to support other languages than
pure C. First the headers embeds the necessary declarations to
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allow direct acces from C++ code, but also we have bindings for
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higher level kind of languages:< / p > < ul > < li > Python: Libvirt comes with direct support for the Python language
(just make sure you installed the libvirt-python package if not
compiling from sources). See below for more informations about
using libvirt with python< / li >
< li > Perl: Daniel Berrange provides < a href = "http://search.cpan.org/~danberr/Sys-Virt-0.1.0/" > bindings for
Perl< / a > .< / li >
< li > OCaml: Richard Jones supplies < a href = "http://libvirt.org/ocaml/" > bindings for OCaml< / a > .< / li >
< li > Ruby: David Lutterkork provides < a href = "http://libvirt.org/ruby/" > bindings for Ruby< / a > .< / li >
< / ul > < p > Support, requests or help for libvirt bindings are welcome on
the < a href = "https://www.redhat.com/mailman/listinfo/libvir-list/" > mailing
list< / a > , as usual try to provide enough background informations
and make sure you use recent version, see the < a href = "bugs.html" > help
page< / a > .< / p > < p > The remaining of this page focuses on the Python bindings.< / p > < p > The Python binding should be complete and are mostly automatically
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generated from the formal description of the API in xml. The bindings are
articulated around 2 classes < code > virConnect< / code > and virDomain mapping to
the C types. Functions in the C API taking either type as argument then
becomes methods for the classes, their name is just stripped from the
virConnect or virDomain(Get) prefix and the first letter gets converted to
lower case, for example the C functions:< / p > < p > < code > int < a href = "html/libvirt-libvirt.html#virConnectNumOfDomains" > virConnectNumOfDomains< / a >
(virConnectPtr conn);< / code > < / p > < p > < code > int < a href = "html/libvirt-libvirt.html#virDomainSetMaxMemory" > virDomainSetMaxMemory< / a >
(virDomainPtr domain, unsigned long memory);< / code > < / p > < p > become< / p > < p > < code > virConn::numOfDomains(self)< / code > < / p > < p > < code > virDomain::setMaxMemory(self, memory)< / code > < / p > < p > This process is fully automated, you can get a summary of the conversion
in the file libvirtclass.txt present in the python dir or in the docs.There
is a couple of function who don't map directly to their C counterparts due to
specificities in their argument conversions:< / p > < ul > < li > < code > < a href = "html/libvirt-libvirt.html#virConnectListDomains" > virConnectListDomains< / a > < / code >
is replaced by < code > virDomain::listDomainsID(self)< / code > which returns
a list of the integer ID for the currently running domains< / li >
< li > < code > < a href = "html/libvirt-libvirt.html#virDomainGetInfo" > virDomainGetInfo< / a > < / code >
is replaced by < code > virDomain::info()< / code > which returns a list of
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< ol > < li > state: one of the state values (virDomainState)< / li >
< li > maxMemory: the maximum memory used by the domain< / li >
< li > memory: the current amount of memory used by the domain< / li >
< li > nbVirtCPU: the number of virtual CPU< / li >
< li > cpuTime: the time used by the domain in nanoseconds< / li >
< / ol > < / li >
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< / ul > < p > So let's look at a simple example inspired from the < code > basic.py< / code >
test found in < code > python/tests/< / code > in the source tree:< / p > < pre > import < span style = "color: #0071FF; background-color: #FFFFFF" > libvirt< / span >
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import sys
conn = < span style = "color: #0071FF; background-color: #FFFFFF" > libvirt< / span > .openReadOnly(None)
if conn == None:
print 'Failed to open connection to the hypervisor'
sys.exit(1)
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try:
dom0 = conn.< span style = "color: #007F00; background-color: #FFFFFF" > lookupByName< / span > ("Domain-0")
except:
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print 'Failed to find the main domain'
sys.exit(1)
print "Domain 0: id %d running %s" % (dom0.< span style = "color: #FF0080; background-color: #FFFFFF" > ID< / span > (), dom0.< span style = "color: #FF0080; background-color: #FFFFFF" > OSType< / span > ())
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print dom0.< span style = "color: #FF0080; background-color: #FFFFFF" > info< / span > ()< / pre > < p > There is not much to comment about it, it really is a straight mapping
from the C API, the only points to notice are:< / p > < ul > < li > the import of the module called < code > < span style = "color: #0071FF; background-color: #FFFFFF" > libvirt< / span > < / code > < / li >
< li > getting a connection to the hypervisor, in that case using the
openReadOnly function allows the code to execute as a normal user.< / li >
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< li > getting an object representing the Domain 0 using < span style = "color: #007F00; background-color: #FFFFFF" > lookupByName< / span > < / li >
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< li > if the domain is not found a libvirtError exception will be raised< / li >
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< li > extracting and printing some informations about the domain using
various < span style = "color: #E50073; background-color: #FFFFFF" > methods< / span >
associated to the virDomain class.< / li >
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< / ul > < / div > < / div > < div class = "linkList2" > < div class = "llinks2" > < h3 class = "links2" > < span > main menu< / span > < / h3 > < ul > < li > < a href = "index.html" > Home< / a > < / li > < li > < a href = "news.html" > Releases< / a > < / li > < li > < a href = "intro.html" > Introduction< / a > < / li > < li > < a href = "architecture.html" > libvirt architecture< / a > < / li > < li > < a href = "downloads.html" > Downloads< / a > < / li > < li > < a href = "format.html" > XML Format< / a > < / li > < li > < a href = "python.html" > Bindings for other languages< / a > < / li > < li > < a href = "errors.html" > Handling of errors< / a > < / li > < li > < a href = "FAQ.html" > FAQ< / a > < / li > < li > < a href = "bugs.html" > Reporting bugs and getting help< / a > < / li > < li > < a href = "windows.html" > Windows support< / a > < / li > < li > < a href = "remote.html" > Remote support< / a > < / li > < li > < a href = "auth.html" > Access control< / a > < / li > < li > < a href = "uri.html" > Connection URIs< / a > < / li > < li > < a href = "hvsupport.html" > Hypervisor support< / a > < / li > < li > < a href = "storage.html" > Storage Management< / a > < / li > < li > < a href = "html/index.html" > API Menu< / a > < / li > < li > < a href = "examples/index.html" > C code examples< / a > < / li > < li > < a href = "ChangeLog.html" > Recent Changes< / a > < / li > < / ul > < / div > < div class = "llinks2" > < h3 class = "links2" > < span > related links< / span > < / h3 > < ul > < li > < a href = "https://www.redhat.com/archives/libvir-list/" > Mail archive< / a > < / li > < li > < a href = "https://bugzilla.redhat.com/bugzilla/buglist.cgi?product=Fedora+Core&component=libvirt&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&bug_status=MODIFIED&short_desc_type=allwordssubstr&short_desc=&long_desc_type=allwordssubstr" > Open bugs< / a > < / li > < li > < a href = "http://virt-manager.et.redhat.com/" > virt-manager< / a > < / li > < li > < a href = "http://search.cpan.org/~danberr/Sys-Virt-0.1.0/" > Perl bindings< / a > < / li > < li > < a href = "http://libvirt.org/ocaml/" > OCaml bindings< / a > < / li > < li > < a href = "http://libvirt.org/ruby/" > Ruby bindings< / a > < / li > < li > < a href = "http://www.cl.cam.ac.uk/Research/SRG/netos/xen/index.html" > Xen project< / a > < / li > < li > < form action = "search.php" enctype = "application/x-www-form-urlencoded" method = "get" > < input name = "query" type = "text" size = "12" value = "Search..." / > < input name = "submit" type = "submit" value = "Go" / > < / form > < / li > < li > < a href = "http://xmlsoft.org/" > < img src = "Libxml2-Logo-90x34.gif" alt = "Made with Libxml2 Logo" / > < / a > < / li > < / ul > < p class = "credits" > Graphics and design by < a href = "mail:dfong@redhat.com" > Diana Fong< / a > < / p > < / div > < / div > < div id = "bottom" > < p class = "p1" > < / p > < / div > < / div > < / body > < / html >
