-(** OCaml bindings for libvirt.
- (C) Copyright 2007 Richard W.M. Jones, Red Hat Inc.
- http://libvirt.org/
+(** OCaml bindings for libvirt. *)
+(* (C) Copyright 2007 Richard W.M. Jones, Red Hat Inc.
+ http://libvirt.org/
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*)
+(**
+ {2 Introduction and examples}
+
+ This is a set of bindings for writing OCaml programs to
+ manage virtual machines through {{:http://libvirt.org/}libvirt}.
+
+ {3 Using libvirt interactively}
+
+ Using the interactive toplevel:
+
+{v
+$ ocaml -I +libvirt
+ Objective Caml version 3.10.0
+
+# #load "unix.cma";;
+# #load "mllibvirt.cma";;
+# let name = "test:///default";;
+val name : string = "test:///default"
+# let conn = Libvirt.Connect.connect_readonly ~name () ;;
+val conn : Libvirt.ro Libvirt.Connect.t = <abstr>
+# Libvirt.Connect.get_node_info conn;;
+ : Libvirt.Connect.node_info =
+{Libvirt.Connect.model = "i686"; Libvirt.Connect.memory = 3145728L;
+ Libvirt.Connect.cpus = 16; Libvirt.Connect.mhz = 1400;
+ Libvirt.Connect.nodes = 2; Libvirt.Connect.sockets = 2;
+ Libvirt.Connect.cores = 2; Libvirt.Connect.threads = 2}
+v}
+
+ {3 Compiling libvirt programs}
+
+ This command compiles a program to native code:
+
+{v
+ocamlopt -I +libvirt mllibvirt.cmxa list_domains.ml -o list_domains
+v}
+
+ {3 Example: Connect to the hypervisor}
+
+ The main modules are {!Libvirt.Connect}, {!Libvirt.Domain} and
+ {!Libvirt.Network} corresponding respectively to the
+ {{:http://libvirt.org/html/libvirt-libvirt.html}virConnect*, virDomain* and virNetwork* functions from libvirt}.
+ For brevity I usually rename these modules like this:
+
+{v
+module C = Libvirt.Connect
+module D = Libvirt.Domain
+module N = Libvirt.Network
+v}
+
+ To get a connection handle, assuming a Xen hypervisor:
+
+{v
+let name = "xen:///"
+let conn = C.connect_readonly ~name ()
+v}
+
+ {3 Example: List running domains}
+
+{v
+open Printf
+
+let n = C.num_of_domains conn in
+let ids = C.list_domains conn n in
+let domains = Array.map (D.lookup_by_id conn) ids in
+Array.iter (
+ fun dom ->
+ printf "%8d %s\n%!" (D.get_id dom) (D.get_name dom)
+) domains;
+v}
+
+ {3 Example: List inactive domains}
+
+{v
+let n = C.num_of_defined_domains conn in
+let names = C.list_defined_domains conn n in
+Array.iter (
+ fun name ->
+ printf "inactive %s\n%!" name
+) names;
+v}
+
+ {3 Example: Print node info}
+
+{v
+let node_info = C.get_node_info conn in
+printf "model = %s\n" node_info.C.model;
+printf "memory = %Ld K\n" node_info.C.memory;
+printf "cpus = %d\n" node_info.C.cpus;
+printf "mhz = %d\n" node_info.C.mhz;
+printf "nodes = %d\n" node_info.C.nodes;
+printf "sockets = %d\n" node_info.C.sockets;
+printf "cores = %d\n" node_info.C.cores;
+printf "threads = %d\n%!" node_info.C.threads;
+
+let hostname = C.get_hostname conn in
+printf "hostname = %s\n%!" hostname;
+
+let uri = C.get_uri conn in
+printf "uri = %s\n%!" uri
+v}
+
+*)
+
+
+(** {2 Programming issues}
+
+ {3 General safety issues}
+
+ Memory allocation / automatic garbage collection of all libvirt
+ objects should be completely safe (except in the specific
+ virterror case noted below). If you find any safety issues or if your
+ pure OCaml program ever segfaults, please contact the author.
+
+ You can force a libvirt object to be freed early by calling
+ the [close] function on the object. This shouldn't affect
+ the safety of garbage collection and should only be used when
+ you want to explicitly free memory. Note that explicitly
+ closing a connection object does nothing if there are still
+ unclosed domain or network objects referencing it.
+
+ Note that even though you hold open (eg) a domain object, that
+ doesn't mean that the domain (virtual machine) actually exists.
+ The domain could have been shut down or deleted by another user.
+ Thus domain objects can through odd exceptions at any time.
+ This is just the nature of virtualisation.
+
+ Virterror has a specific design error which means that the
+ objects embedded in a virterror exception message are only
+ valid as long as the connection handle is still open. This
+ is a design flaw in the C code of libvirt and we cannot fix
+ or work around it in the OCaml bindings.
+
+ {3 Backwards and forwards compatibility}
+
+ OCaml-libvirt is backwards and forwards compatible with
+ any libvirt >= 0.2.1. One consequence of this is that
+ your program can dynamically link to a {i newer} version of
+ libvirt than it was compiled with, and it should still
+ work.
+
+ When we link to an older version of libvirt.so, there may
+ be missing functions. If ocaml-libvirt was compiled with
+ gcc, then these are turned into OCaml {!Libvirt.Not_supported}
+ exceptions.
+
+ We don't support libvirt < 0.2.1, and never will so don't ask us.
+
+ {3 Threads}
+
+ You can issue multiple concurrent libvirt requests in
+ different threads. However you must follow this rule:
+ Each thread must have its own separate libvirt connection, {i or}
+ you must implement your own mutex scheme to ensure that no
+ two threads can ever make concurrent calls using the same
+ libvirt connection.
+
+ (Note that multithreaded code is not well tested. If you find
+ bugs please report them.)
+
+ {3 Initialisation}
+
+ Libvirt requires all callers to call virInitialize before
+ using the library. This is done automatically for you by
+ these bindings when the program starts up, and we believe
+ that the way this is done is safe.
+
+ {2 Reference}
+*)
+
type uuid = string
-(** This is a "raw" UUID, ie. a packed string of bytes. *)
+ (** This is a "raw" UUID, ie. a packed string of bytes. *)
type xml = string
-(** Type of XML (an uninterpreted string of bytes). Use PXP, expat,
- xml-light, etc. if you want to do anything useful with the XML.
-*)
+ (** Type of XML (an uninterpreted string of bytes). Use PXP, expat,
+ xml-light, etc. if you want to do anything useful with the XML.
+ *)
type filename = string
-(** A filename. *)
+ (** A filename. *)
val get_version : ?driver:string -> unit -> int * int
(** [get_version ()] returns the library version in the first part
val uuid_string_length : int
(** Length of UUID strings. *)
-(* These phantom types are used to ensure the type-safety of read-only
- * versus read-write connections. For more information see:
- * http://caml.inria.fr/pub/ml-archives/caml-list/2004/07/80683af867cce6bf8fff273973f70c95.en.html
- *)
type rw = [`R|`W]
type ro = [`R]
+ (** These
+ {{:http://caml.inria.fr/pub/ml-archives/caml-list/2004/07/80683af867cce6bf8fff273973f70c95.en.html}phantom types}
+ are used to ensure the type-safety of read-only
+ versus read-write connections.
+
+ All connection/domain/etc. objects are marked with
+ a phantom read-write or read-only type, and trying to
+ pass a read-only object into a function which could
+ mutate the object will cause a compile time error.
+
+ Each module provides a function like {!Libvirt.Connect.const}
+ to demote a read-write object into a read-only object. The
+ opposite operation is, of course, not allowed.
+
+ If you want to handle both read-write and read-only
+ connections at runtime, use a variant similar to this:
+{v
+type conn_t =
+ | No_connection
+ | Read_only of Libvirt.ro Libvirt.Connect.t
+ | Read_write of Libvirt.rw Libvirt.Connect.t
+v}
+ See also the source of [mlvirsh].
+ *)
+
+(** {3 Connections} *)
module Connect :
sig
connection object.
*)
+(** {3 Domains} *)
+
module Domain :
sig
type 'rw t
domain object.
*)
+(** {3 Networks} *)
+
module Network :
sig
type 'rw t
network object.
*)
+(** {3 Error handling and exceptions} *)
+
module Virterror :
sig
type code =
not supported at either compile or run time. This applies to
any libvirt function added after version 0.2.1.
- See also [http://libvirt.org/hvsupport.html]
+ See also {{:http://libvirt.org/hvsupport.html}http://libvirt.org/hvsupport.html}
*)
git.annexia.org / virt-top.git / commitdiff