From d2978caea72572263829df6ce6297df3b97aaaa0 Mon Sep 17 00:00:00 2001 From: Pavel Hrdina Date: Thu, 25 Mar 2021 16:58:44 +0100 Subject: [PATCH] docs: convert 'python' page to rst Signed-off-by: Pavel Hrdina Signed-off-by: Peter Krempa Reviewed-by: Pavel Hrdina --- docs/meson.build | 2 +- docs/python.html.in | 72 ----------------------------------------- docs/python.rst | 79 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 80 insertions(+), 73 deletions(-) delete mode 100644 docs/python.html.in create mode 100644 docs/python.rst diff --git a/docs/meson.build b/docs/meson.build index e73cb3c6cd..9022e761ca 100644 --- a/docs/meson.build +++ b/docs/meson.build @@ -29,7 +29,6 @@ docs_html_in_files = [ 'formatstoragecaps', 'index', 'internals', - 'python', 'remote', 'storage', 'tlscerts', @@ -102,6 +101,7 @@ docs_rst_files = [ 'php', 'platforms', 'programming-languages', + 'python', 'securityprocess', 'strategy', 'styleguide', diff --git a/docs/python.html.in b/docs/python.html.in deleted file mode 100644 index 0f804da8c3..0000000000 --- a/docs/python.html.in +++ /dev/null @@ -1,72 +0,0 @@ - - - - -

Python API bindings

- -

The Python binding should be complete and are mostly automatically -generated from the formal description of the API in xml. The bindings are -articulated around 2 classes virConnect 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:

-

- int virConnectNumOfDomains -(virConnectPtr conn); -

-

- int virDomainSetMaxMemory -(virDomainPtr domain, unsigned long memory); -

-

become

-

- virConnect::numOfDomains(self) -

-

- virDomain::setMaxMemory(self, memory) -

-

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:

-
    -
  • virConnectListDomains - is replaced by virDomain::listDomainsID(self) which returns - a list of the integer ID for the currently running domains
    • -
  • virDomainGetInfo - is replaced by virDomain::info() which returns a list of -
    1. state: one of the state values (virDomainState)
    2. maxMemory: the maximum memory used by the domain
    3. memory: the current amount of memory used by the domain
    4. nbVirtCPU: the number of virtual CPU
    5. cpuTime: the time used by the domain in nanoseconds
    • -
-

So let's look at a simple example:

- 
import libvirt
-import sys
-
-try:
-    conn = libvirt.openReadOnly(None)
-except libvirt.libvirtError:
-    print('Failed to open connection to the hypervisor')
-    sys.exit(1)
-
-try:
-    dom0 = conn.lookupByName("Domain-0")
-except libvirt.libvirtError:
-    print('Failed to find the main domain')
-    sys.exit(1)
-
-print("Domain 0: id %d running %s" % (dom0.ID(), dom0.OSType()))
-print(dom0.info())
-

There is not much to comment about it, it really is a straight mapping -from the C API, the only points to notice are:

-
    -
  • the import of the module called libvirt
    • -
  • getting a connection to the hypervisor, in that case using the - openReadOnly function allows the code to execute as a normal user.
    • -
  • getting an object representing the Domain 0 using lookupByName
    • -
  • if the domain is not found a libvirtError exception will be raised
    • -
  • extracting and printing some information about the domain using - various methods - associated to the virDomain class.
    • -
- - diff --git a/docs/python.rst b/docs/python.rst new file mode 100644 index 0000000000..aa1bddc4e1 --- /dev/null +++ b/docs/python.rst @@ -0,0 +1,79 @@ +=================== +Python API bindings +=================== + +The Python binding should be complete and are mostly automatically generated +from the formal description of the API in xml. The bindings are articulated +around 2 classes ``virConnect`` 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: + +``int virConnectNumOfDomains (virConnectPtr conn);`` + +``int virDomainSetMaxMemory (virDomainPtr domain, unsigned long memory);`` + +become + +``virConnect::numOfDomains(self)`` + +``virDomain::setMaxMemory(self, memory)`` + +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: + +- ``virConnectListDomains`` is replaced by ``virDomain::listDomainsID(self)`` + which returns a list of the integer ID for the currently running domains + +- ``virDomainGetInfo`` is replaced by ``virDomain::info()`` which returns a + list of + + #. state: one of the state values (virDomainState) + + #. maxMemory: the maximum memory used by the domain + + #. memory: the current amount of memory used by the domain + + #. nbVirtCPU: the number of virtual CPU + + #. cpuTime: the time used by the domain in nanoseconds + +So let's look at a simple example: + +:: + + import libvirt + import sys + + try: + conn = libvirt.openReadOnly(None) + except libvirt.libvirtError: + print('Failed to open connection to the hypervisor') + sys.exit(1) + + try: + dom0 = conn.lookupByName("Domain-0") + except libvirt.libvirtError: + print('Failed to find the main domain') + sys.exit(1) + + print("Domain 0: id %d running %s" % (dom0.ID(), dom0.OSType())) + print(dom0.info()) + +There is not much to comment about it, it really is a straight mapping from the +C API, the only points to notice are: + +- the import of the module called ``libvirt`` + +- getting a connection to the hypervisor, in that case using the openReadOnly + function allows the code to execute as a normal user. + +- getting an object representing the Domain 0 using lookupByName + +- if the domain is not found a libvirtError exception will be raised + +- extracting and printing some information about the domain using various + methods associated to the virDomain class.