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DM
1====================================
2Setup PVE v2 Development Environment
3====================================
4
51. Install Debian 'squeeze'
62. Install prerequisites for development environment:
7
8apt-get -y install build-essential subversion debhelper autotools-dev \
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
243. Download and install the following svn modules in order from top to bottom:
25
26svn://devel.proxmox.com/var/svn/pve/
27
28libqb/trunk
29corosync/trunk
30openais/trunk
31pve-common/trunk
32pve-cluster/trunk
33redhat-cluster/trunk
34pve-access-control/trunk
35pve-storage/pve2
36pve-qemu-kvm/pve2
37qemu-server/pve2
38vncterm/pve2
39pve-manager/pve2
40pve-kernel-2.6.32-rh/pve2
41
42Most source can be installed with 'make dinstall' command.
43
444. Reboot the system.
455. Learn to use the quilt patch scripts.
466. Happy coding.
47
48There is an experimental package containing the API documentation
49as ExtJS application:
50
51pve2-api-doc/trunk
52
53
54REST vs. SOAP
55=============
56
57We decided to change our SOAP API (1.X) and use a REST like API. The
58concept is described in [1] (Resource Oriented Architecture
59(ROA)). The main advantage is that we are able to remove a lot of code
60(the whole SOAP stack) to reduce software complexity.
61
62We also moved away from server side content generation. Instead we use
63the ExtJS Rich Internet Application Framework
64(http://www.sencha.com).
65
66That framework, like any other AJAX toolkit, can talk directly to the
67REST API using JSON. So we were able to remove the server side
68template toolkit completely.
69
70JSON and JSON Schema
71====================
72
73We use JSON as data format, because it is simple and parse-able by any
74web browser.
75
76Additionally, we use JSON Schema [2] to formally describe our API. So
77we can automatically generate the whole API Documentation, and we can
78verify all parameters and return values.
79
80An great side effect was that we are able to use JSON Schema to
81produce command line argument parsers automatically. In fact, the REST
82API and the command line tools use the same code.
83
84Object linkage is done using the JSON Hyper Schema (links property).
85
86A small utility called 'pvesh' exposes the whole REST API on the command
87line.
88
89So here is a summary of the advantage:
90
91 - easy, human readable data format (native web browser format)
92 - automatic parameter verification (we can also verify return values)
93 - automatic generation of API documentation
94 - easy way to create command line tools (using same API).
95
96API Implementation (PVE::RESTHandler)
97=====================================
98
99All classes exposing methods on the API use PVE::RESTHandler as base class.
100
101 use base qw(PVE::RESTHandler);
102
103To expose methods, one needs to call register_method():
104
105 __PACKAGE__->register_method ($schema);
106
107Where $schema is a PVE method schema as described in
108PVE::JSONSchema. It includes a description of parameters and return
109values, and a reference to the actual code
110
111__PACKAGE__->register_method ({
112 name => 'echo',
113 path => 'echo',
114 method => 'GET',
115 description => "simple return value of parameter 'text'",
116 parameters => {
117 additionalProperties => 0,
118 properties => {
119 text => {
120 type => 'string',
121 }
122 },
123 },
124 returns => {
125 type => 'string',
126 },
127 code => sub {
128 my ($conn, $resp, $param) = @_;
129
130 return $param->{text};
131 }
132});
133
134The 'name' property is only used if you want to call the method
135directly from Perl. You can do that using:
136
137 print __PACKAGE__->echo({ text => "a test" });
138
139We use Perl's AUTOLOAD feature to implement this. Note: You need to
140pass parameters a HASH reference.
141
142There is a special helper method called cli_handler(). This is used by
143the CLIHandler Class for command line tools, where you want to pass
144arguments as array of strings. This uses Getopt::Long to parse parameters.
145
146There is a second way to map names to methods - using the 'path'
147property. And you can register subclasses. That way you can set up a
148filesystem like hierarchy to access methods.
149
150Here is an example:
151----------------------------
152package C1;
153
154__PACKAGE__->register_method ({
155 subclass => "C2",
156 path => 'sub2',
157});
158
159
160__PACKAGE__->register_method ({
161 name => 'list1',
162 path => 'index',
163 method => 'GET',
164 ...
165});
166
167package C2;
168
169__PACKAGE__->register_method ({
170 name => 'list2',
171 path => 'index',
172 method => 'GET',
173 ...
174});
175-------------------------------
176
177The utily method find_handler (in PVE::RESTHandler) can be use to do
178'path' related method lookups.
179
180C1->find_handler('GET', "/index") => C1::list1
181C1->find_handler('GET', "/sub2/index") => C2::list2
182
183The HTTP server use the URL (a path) to find the corresponding method.
184
185
186References
187==========
188[1] RESTful Web Services
189Web services for the real world
190
191By
192 Leonard Richardson, Sam Ruby
193Publisher:
194 O'Reilly Media
195Released:
196 May 2007
197
198[2] JSON Schema links: http://json-schema.org/