add .gitignore file, remove svn leftover
[pve-common.git] / README.dev
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1====================================
2Setup PVE v2 Development Environment
3====================================
4
51. Install Debian 'squeeze'
62. Install prerequisites for development environment:
7
7da024b1 8apt-get -y install build-essential git-core debhelper autotools-dev \
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9doxygen check pkg-config libnss3-dev groff quilt dpatch libxml2-dev \
10libncurses5-dev libslang2-dev libldap2-dev xsltproc python-pexpect \
11python-pycurl libdbus-1-dev openipmi sg3-utils libnet-snmp-perl \
12libnet-telnet-perl snmp python-openssl libxml2-utils automake autoconf \
13libsqlite3-dev sqlite3 libfuse-dev libglib2.0-dev librrd-dev \
14librrds-perl rrdcached lintian libdevel-cycle-perl libjson-perl \
15liblinux-inotify2-perl libio-stringy-perl unzip fuse-utils \
16libcrypt-openssl-random-perl libcrypt-openssl-rsa-perl \
17libauthen-pam-perl libterm-readline-gnu-perl libssl-dev open-iscsi \
18libapache2-mod-perl2 libfilesys-df-perl libfile-readbackwards-perl \
19libpci-dev texi2html libgnutls-dev libsdl1.2-dev bridge-utils \
20libvncserver0 rpm2cpio apache2-mpm-prefork libintl-perl \
21libapache2-request-perl libnet-dns-perl vlan libio-socket-ssl-perl \
22libfile-sync-perl ifenslave-2.6 libnet-ldap-perl console-data
23
7da024b1 243. Download and install the following git modules in order from top to bottom:
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7da024b1 26# git clone git://git.proxmox.com/git/<PACKAGE.git>
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28You currently need the following packages:
29
30libqb.git
31corosync-pve.git
32openais-pve.git
33pve-common.git
34pve-cluster.git
35redhat-cluster-pve.git
36pve-access-control.git
37pve-storage.git
38pve-qemu-kvm.git
39qemu-server.git
40vncterm.git
41pve-manager.git
42pve-kernel-2.6.32.git
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43
44Most source can be installed with 'make dinstall' command.
45
464. Reboot the system.
475. Learn to use the quilt patch scripts.
486. Happy coding.
49
50There is an experimental package containing the API documentation
51as ExtJS application:
52
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53pve2-api-doc.git
54
55You can view the source code at:
56
57https://git.proxmox.com
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58
59
60REST vs. SOAP
61=============
62
63We decided to change our SOAP API (1.X) and use a REST like API. The
64concept is described in [1] (Resource Oriented Architecture
65(ROA)). The main advantage is that we are able to remove a lot of code
66(the whole SOAP stack) to reduce software complexity.
67
68We also moved away from server side content generation. Instead we use
69the ExtJS Rich Internet Application Framework
70(http://www.sencha.com).
71
72That framework, like any other AJAX toolkit, can talk directly to the
73REST API using JSON. So we were able to remove the server side
74template toolkit completely.
75
76JSON and JSON Schema
77====================
78
79We use JSON as data format, because it is simple and parse-able by any
80web browser.
81
82Additionally, we use JSON Schema [2] to formally describe our API. So
83we can automatically generate the whole API Documentation, and we can
84verify all parameters and return values.
85
86An great side effect was that we are able to use JSON Schema to
87produce command line argument parsers automatically. In fact, the REST
88API and the command line tools use the same code.
89
90Object linkage is done using the JSON Hyper Schema (links property).
91
92A small utility called 'pvesh' exposes the whole REST API on the command
93line.
94
95So here is a summary of the advantage:
96
97 - easy, human readable data format (native web browser format)
98 - automatic parameter verification (we can also verify return values)
99 - automatic generation of API documentation
100 - easy way to create command line tools (using same API).
101
102API Implementation (PVE::RESTHandler)
103=====================================
104
105All classes exposing methods on the API use PVE::RESTHandler as base class.
106
107 use base qw(PVE::RESTHandler);
108
109To expose methods, one needs to call register_method():
110
111 __PACKAGE__->register_method ($schema);
112
113Where $schema is a PVE method schema as described in
114PVE::JSONSchema. It includes a description of parameters and return
115values, and a reference to the actual code
116
117__PACKAGE__->register_method ({
118 name => 'echo',
119 path => 'echo',
120 method => 'GET',
121 description => "simple return value of parameter 'text'",
122 parameters => {
123 additionalProperties => 0,
124 properties => {
125 text => {
126 type => 'string',
127 }
128 },
129 },
130 returns => {
131 type => 'string',
132 },
133 code => sub {
134 my ($conn, $resp, $param) = @_;
135
136 return $param->{text};
137 }
138});
139
140The 'name' property is only used if you want to call the method
141directly from Perl. You can do that using:
142
143 print __PACKAGE__->echo({ text => "a test" });
144
145We use Perl's AUTOLOAD feature to implement this. Note: You need to
146pass parameters a HASH reference.
147
148There is a special helper method called cli_handler(). This is used by
149the CLIHandler Class for command line tools, where you want to pass
150arguments as array of strings. This uses Getopt::Long to parse parameters.
151
152There is a second way to map names to methods - using the 'path'
153property. And you can register subclasses. That way you can set up a
154filesystem like hierarchy to access methods.
155
156Here is an example:
157----------------------------
158package C1;
159
160__PACKAGE__->register_method ({
161 subclass => "C2",
162 path => 'sub2',
163});
164
165
166__PACKAGE__->register_method ({
167 name => 'list1',
168 path => 'index',
169 method => 'GET',
170 ...
171});
172
173package C2;
174
175__PACKAGE__->register_method ({
176 name => 'list2',
177 path => 'index',
178 method => 'GET',
179 ...
180});
181-------------------------------
182
183The utily method find_handler (in PVE::RESTHandler) can be use to do
184'path' related method lookups.
185
186C1->find_handler('GET', "/index") => C1::list1
187C1->find_handler('GET', "/sub2/index") => C2::list2
188
189The HTTP server use the URL (a path) to find the corresponding method.
190
191
192References
193==========
194[1] RESTful Web Services
195Web services for the real world
196
197By
198 Leonard Richardson, Sam Ruby
199Publisher:
200 O'Reilly Media
201Released:
202 May 2007
203
204[2] JSON Schema links: http://json-schema.org/