README.dev

   1 ====================================
   2 Setup PVE Development Environment
   3 ====================================
   4
   5 1.  Install Debian 'jessie'
   6 2.  Install prerequisites for development environment:
   7
   8 # new jessie depends
   9 apt-get -y install build-essential git-core debhelper autotools-dev \
  10 doxygen check pkg-config groff quilt dpatch automake autoconf libtool  \
  11 lintian libdevel-cycle-perl libjson-perl libcommon-sense-perl     \
  12 liblinux-inotify2-perl libio-stringy-perl libstring-shellquote-perl  \
  13 dh-systemd rpm2cpio libsqlite3-dev sqlite3 libglib2.0-dev librrd-dev \
  14 librrds-perl rrdcached libdigest-hmac-perl libxml-parser-perl \
  15 gdb libcrypt-openssl-random-perl libcrypt-openssl-rsa-perl \
  16 libnet-ldap-perl libauthen-pam-perl libjson-xs-perl libterm-readline-gnu-perl oathtool libmime-base32-perl liboath0 libpci-dev texi2html libsdl1.2-dev \
  17 libgnutls28-dev libspice-protocol-dev xfslibs-dev libnuma-dev libaio-dev \
  18 libspice-server-dev libusbredirparser-dev glusterfs-common libusb-1.0-0-dev \
  19 librbd-dev libpopt-dev iproute bridge-utils numactl glusterfs-common \
  20 ceph-common python-ceph libgoogle-perftools4 libfile-chdir-perl lvm2 \
  21 glusterfs-client liblockfile-simple-perl libsystemd-daemon-dev \
  22 libreadline-gplv2-dev libio-multiplex-perl libnetfilter-log-dev \
  23 libipset3 ipset socat libsasl2-dev
  24
  25 # old wheezy depends
  26 apt-get -y install build-essential git-core debhelper autotools-dev \
  27 doxygen check pkg-config libnss3-dev groff quilt dpatch libxml2-dev \
  28 libncurses5-dev libslang2-dev libldap2-dev xsltproc python-pexpect \
  29 python-pycurl libdbus-1-dev openipmi sg3-utils libnet-snmp-perl \
  30 libnet-telnet-perl snmp python-openssl libxml2-utils automake autoconf \
  31 libsqlite3-dev sqlite3 libfuse-dev libglib2.0-dev librrd-dev \
  32 librrds-perl rrdcached lintian libdevel-cycle-perl libjson-perl \
  33 liblinux-inotify2-perl libio-stringy-perl unzip fuse-utils \
  34 libcrypt-openssl-random-perl libcrypt-openssl-rsa-perl \
  35 libauthen-pam-perl libterm-readline-gnu-perl libssl-dev open-iscsi \
  36 libapache2-mod-perl2 libfilesys-df-perl libfile-readbackwards-perl \
  37 libpci-dev texi2html libgnutls-dev libsdl1.2-dev bridge-utils \
  38 libvncserver0 rpm2cpio  apache2-mpm-prefork libintl-perl \
  39 libapache2-request-perl libnet-dns-perl vlan libio-socket-ssl-perl \
  40 libfile-sync-perl ifenslave-2.6 libnet-ldap-perl console-data \
  41 libtool dietlibc-dev liblocale-po-perl libstring-shellquote-perl \
  42 libio-multiplex-perl liblockfile-simple-perl
  43
  44 3.  Download and install the following git modules in order from top to bottom:
  45
  46 # git clone git://git.proxmox.com/git/<PACKAGE.git>
  47
  48 You currently need the following packages:
  49
  50 libqb.git
  51 corosync-pve.git
  52 openais-pve.git
  53 pve-common.git
  54 pve-cluster.git
  55 redhat-cluster-pve.git
  56 lvm.git
  57 pve-access-control.git
  58 pve-storage.git
  59 pve-qemu-kvm.git
  60 qemu-server.git
  61 vncterm.git
  62 vzquota.git
  63 vzctl.git
  64 fence-agents-pve.git
  65 resource-agents-pve.git
  66 pve-manager.git
  67 pve-kernel-2.6.32.git
  68 libiscsi.git
  69 gfs2-utils.git
  70 ksm-control-daemon.git
  71
  72 Most packages can be installed with 'make dinstall' command.
  73
  74 4.  Reboot the system.
  75 5.  Learn to use the quilt patch scripts.
  76 6.  Happy coding.
  77
  78 There is an experimental package containing the API documentation
  79 as ExtJS application:
  80
  81 pve2-api-doc.git
  82
  83 You can view the source code at:
  84
  85 https://git.proxmox.com
  86
  87
  88 REST vs. SOAP
  89 =============
  90
  91 We decided to change our SOAP API (1.X) and use a REST like API. The
  92 concept is described in [1] (Resource Oriented Architecture
  93 (ROA)). The main advantage is that we are able to remove a lot of code
  94 (the whole SOAP stack) to reduce software complexity.
  95
  96 We also moved away from server side content generation. Instead we use
  97 the ExtJS Rich Internet Application Framework
  98 (http://www.sencha.com).
  99
 100 That framework, like any other AJAX toolkit, can talk directly to the
 101 REST API using JSON. So we were able to remove the server side
 102 template toolkit completely.
 103
 104 JSON and JSON Schema
 105 ====================
 106
 107 We use JSON as data format, because it is simple and parse-able by any
 108 web browser.
 109
 110 Additionally, we use JSON Schema [2] to formally describe our API. So
 111 we can automatically generate the whole API Documentation, and we can
 112 verify all parameters and return values.
 113
 114 A great side effect was that we are able to use JSON Schema to
 115 produce command line argument parsers automatically. In fact, the REST
 116 API and the command line tools use the same code.
 117
 118 Object linkage is done using the JSON Hyper Schema (links property).
 119
 120 A small utility called 'pvesh' exposes the whole REST API on the command
 121 line.
 122
 123 So here is a summary of the advantage:
 124
 125    - easy, human readable data format (native web browser format)
 126    - automatic parameter verification (we can also verify return values)
 127    - automatic generation of API documentation
 128    - easy way to create command line tools (using same API).
 129
 130 API Implementation (PVE::RESTHandler)
 131 =====================================
 132
 133 All classes exposing methods on the API use PVE::RESTHandler as base class.
 134
 135   use base qw(PVE::RESTHandler);
 136
 137 To expose methods, one needs to call register_method():
 138
 139   __PACKAGE__->register_method ($schema);
 140
 141 Where $schema is a PVE method schema as described in
 142 PVE::JSONSchema. It includes a description of parameters and return
 143 values, and a reference to the actual code
 144
 145 __PACKAGE__->register_method ({
 146     name => 'echo',
 147     path => 'echo',
 148     method => 'GET',
 149     description => "simple return value of parameter 'text'",
 150     parameters => {
 151         additionalProperties => 0,
 152         properties => {
 153             text => {
 154                  type => 'string',
 155             }
 156         },
 157     },
 158     returns => {
 159         type => 'string',
 160     },
 161     code => sub {
 162         my ($conn, $resp, $param) = @_;
 163
 164         return $param->{text};
 165     }
 166 });
 167
 168 The 'name' property is only used if you want to call the method
 169 directly from Perl. You can do that using:
 170
 171   print __PACKAGE__->echo({ text => "a test" });
 172
 173 We use Perl's AUTOLOAD feature to implement this. Note: You need to
 174 pass parameters a HASH reference.
 175
 176 There is a special helper method called cli_handler(). This is used by
 177 the CLIHandler Class for command line tools, where you want to pass
 178 arguments as array of strings. This uses Getopt::Long to parse parameters.
 179
 180 There is a second way to map names to methods - using the 'path'
 181 property.  And you can register subclasses. That way you can set up a
 182 filesystem like hierarchy to access methods.
 183
 184 Here is an example:
 185 ----------------------------
 186 package C1;
 187
 188 __PACKAGE__->register_method ({
 189     subclass => "C2",
 190     path => 'sub2',
 191 });
 192
 193
 194 __PACKAGE__->register_method ({
 195     name => 'list1',
 196     path => 'index',
 197     method => 'GET',
 198     ...
 199 });
 200
 201 package C2;
 202
 203 __PACKAGE__->register_method ({
 204     name => 'list2',
 205     path => 'index',
 206     method => 'GET',
 207     ...
 208 });
 209 -------------------------------
 210
 211 The utily method find_handler (in PVE::RESTHandler) can be use to do
 212 'path' related method lookups.
 213
 214 C1->find_handler('GET', "/index")      => C1::list1
 215 C1->find_handler('GET', "/sub2/index") => C2::list2
 216
 217 The HTTP server use the URL (a path) to find the corresponding method.
 218
 219
 220 References
 221 ==========
 222 [1] RESTful Web Services
 223 Web services for the real world
 224
 225 By
 226     Leonard Richardson, Sam Ruby
 227 Publisher:
 228     O'Reilly Media
 229 Released:
 230     May 2007
 231
 232 [2] JSON Schema links: http://json-schema.org/