1Module::AutoInstall(3)User Contributed Perl DocumentationModule::AutoInstall(3)
2
6 Module::AutoInstall - Automatic install of dependencies via CPAN
7
9 In Makefile.PL, with Module::Install available on the author's system:
10 use inc::Module::Install;
12 name 'Joe-Hacker';
14 abstract 'Perl Interface to Joe Hacker';
15 author 'Joe Hacker <joe@hacker.org>';
16 include 'Module::AutoInstall';
17 requires 'Module0'; # mandatory modules
19 feature 'Feature1',
21 -default => 0,
22 'Module2' => '0.1';
23 feature 'Feature2',
25 -default => 0,
26 'Module3' => '1.0';
27 auto_install(
29 make_args => '--hello', # option(s) for CPAN::Config
30 force => 1, # pseudo-option to force install
31 do_once => 1, # skip previously failed modules
32 );
33 WriteAll;
35 Invoking the resulting Makefile.PL:
37 % perl Makefile.PL # interactive behaviour
39 % perl Makefile.PL --defaultdeps # accept default value on prompts
40 % perl Makefile.PL --checkdeps # check only, no Makefile produced
41 % perl Makefile.PL --skipdeps # ignores all dependencies
42 % perl Makefile.PL --testonly # don't write installation targets
43 Note that the trailing 'deps' of arguments may be omitted, too.
45 Using "--defaultdeps" will make Makefile.PL behave similarly to a
47 regular Makefile.PL file with "PREREQ_PM" dependencies.
48 One can use environment variables (see "ENVIRONMENT") below to set a
50 default behavior instead of specifying it in the command line for every
51 invocation of Makefile.PL.
52 Using make (or nmake):
54 % make [all|test|install] # install dependencies first
56 % make checkdeps # same as the --checkdeps above
57 % make installdeps # install dependencies only
58
60 Module::AutoInstall lets module writers to specify a more sophisticated
61 form of dependency information than the "PREREQ_PM" option offered by
62 ExtUtils::MakeMaker.
63 This module works best with the Module::Install framework, a drop-in
65 replacement for MakeMaker. However, this module also supports
66 Makefile.PL files based on MakeMaker; see "EXAMPLES" for instructions.
67 Prerequisites and Features
69 Prerequisites are grouped into features, and the user could choose
70 yes/no on each one's dependencies; the module writer may also supply a
71 boolean value via "-default" to specify the default choice.
72 The Core Features marked by the name "-core" will double-check with the
74 user, if the user chooses not to install the mandatory modules. This
75 differs from the pre-0.26 'silent install' behaviour.
76 Starting from version 0.27, if "-core" is set to the string "all"
78 (case-insensitive), every feature will be considered mandatory.
79 The dependencies are expressed as pairs of "Module" => "version" inside
81 an array reference. If the order does not matter, and there are no
82 "-default", "-tests" or "-skiptests" directives for that feature, you
83 may also use a hash reference.
84 The Installation Process
86 Once Module::AutoInstall has determined which module(s) are needed, it
87 checks whether it's running under the CPAN shell and should therefore
88 let CPAN handle the dependency.
89 Finally, the "WriteMakefile()" is overridden to perform some additional
91 checks, as well as skips tests associated with disabled features by the
92 "-tests" option.
93 The actual installation happens at the end of the "make config" target;
95 both "make test" and "make install" will trigger the installation of
96 required modules.
97 If it's not running under CPAN, the installer will probe for an active
99 connection by trying to resolve the domain "cpan.org", and check for
100 the user's permission to use CPAN. If all went well, a separate
101 CPAN instance is created to install the required modules.
102 If you have the CPANPLUS package installed in your system, it is
104 preferred by default over CPAN; it also accepts some extra options
105 (e.g. "-target => 'skiptest', -skiptest => 1" to skip testing).
106 All modules scheduled to be installed will be deleted from %INC first,
108 so ExtUtils::MakeMaker will check the newly installed modules.
109 Additionally, you could use the "make installdeps" target to install
111 the modules, and the "make checkdeps" target to check dependencies
112 without actually installing them; the "perl Makefile.PL --checkdeps"
113 command has an equivalent effect.
114 If the Makefile.PL itself needs to use an independent module (e.g.
116 Acme::KillarApp, v1.21 or greater), then use something like below:
117 BEGIN {
119 require Module::AutoInstall;
120 # the first argument is an arrayref of the -config flags
121 Module::AutoInstall->install([], 'Acme::KillerApp' => 1.21);
122 }
123 use Acme::KillerApp 1.21;
124 Module::AutoInstall->import(
126 # ... arguments as usual ...
127 );
128 Note the version test in the use clause; if you are so close to the
130 cutting edge that Acme::KillerApp 1.20 is the latest version on CPAN,
131 this will prevent your module from going awry.
132 User-Defined Hooks
134 User-defined pre-installation and post-installation hooks are available
135 via "MY::preinstall" and "MY::postinstall" subroutines, as shown below:
136 # pre-install handler; takes $module_name and $version
138 sub MY::preinstall { return 1; } # return false to skip install
139 # post-install handler; takes $module_name, $version, $success
141 sub MY::postinstall { return; } # the return value doesn't matter
142 Note that since Module::AutoInstall performs installation at the time
144 of "use" (i.e. before perl parses the remainder of Makefile.PL), you
145 have to declare those two handlers before the "use" statement for them
146 to take effect.
147 If the user did not choose to install a module or it already exists on
149 the system, neither of the handlers is invoked. Both handlers are
150 invoked exactly once for each module when installation is attempted.
151 "MY::preinstall" takes two arguments, $module_name and $version; if it
153 returns a false value, installation for that module will be skipped,
154 and "MY::postinstall" won't be called at all.
155 "MY::postinstall" takes three arguments, $module_name, $version and
157 $success. The last one denotes whether the installation succeeded or
158 not: 1 means installation completed successfully, 0 means failure
159 during install, and "undef" means that the installation was not
160 attempted at all, possibly due to connection problems, or that module
161 does not exist on CPAN at all.
162 Customized "MY::postamble"
164 Starting from version 0.43, Module::AutoInstall supports modules that
165 require a "MY::postamble" subroutine in their Makefile.PL. The user-
166 defined "MY::postamble", if present, is responsible for calling
167 "Module::AutoInstall::postamble" and include the output in its return
168 value.
169 For example, the DBD::* (database driver) modules for the Perl DBI are
171 required to include the postamble generated by the function
172 "dbd_postamble", so their Makefile.PL may contain lines like this:
173 sub MY::postamble {
175 return &Module::AutoInstall::postamble . &dbd_postamble;
176 }
177 Note that the Module::AutoInstall module does not export the
179 "postamble" function, so the name should always be fully qualified.
180
182 Module::AutoInstall will add "UNINST=1" to your make install flags if
183 your effective uid is 0 (root), unless you explicitly disable it by
184 setting CPAN's "make_install_arg" configuration option (or the
185 "makeflags" option of CPANPLUS) to include "UNINST=0". This may cause
186 dependency problems if you are using a fine-tuned directory structure
187 for your site. Please consult "FAQ" in CPAN for an explanation in
188 detail.
189 If either version or Sort::Versions is available, they will be used to
191 compare the required version with the existing module's version and the
192 CPAN module's. Otherwise it silently falls back to use cmp. This may
193 cause inconsistent behaviours in pathetic situations.
194
196 Module::AutoInstall uses a single environment variable,
197 "PERL_AUTOINSTALL". It is taken as the command line argument passed to
198 Makefile.PL; you could set it to "--alldeps", "--defaultdeps" or
199 "--skipdeps" to avoid all interactive behaviour.
200 "--alldeps" will install all features, while "--defaultdeps" will only
202 install features for which the default answer is 'y'.
203 "--skipdeps" will refrain from loading CPAN and not install anything,
205 unless you're running under CPAN or CPANPLUS, in which case required
206 dependencies will be installed.
207 It also read from the "PERL_EXTUTILS_AUTOINSTALL" environment variable
209 if "PERL_AUTOINSTALL" is not defined.
210
212 Module::Install
213 perlmodlib, ExtUtils::MakeMaker, Sort::Versions, CPAN, CPANPLUS
215
217 Audrey Tang <autrijus@autrijus.org>
218 Adam Kennedy <adamk@cpan.org>
220 Matt S Trout <mst@shadowcat.co.u>
222
224 Report a ticket to bugs-Module-Install <at> rt.cpan.org and cc Matt - I
225 appear to have volunteered as primary maintainer for this stuff so if
226 you run into any problems please tell me
227
229 Copyright 2001, 2002, 2003, 2004, 2005, 2006 by Audrey Tang
230 Some parts copyright 2006 Adam Kennedy
232 This program is free software; you can redistribute it and/or modify it
234 under the same terms as Perl itself.
235 See <http://www.perl.com/perl/misc/Artistic.html>
237perl v5.10.1 2009-05-27 Module::AutoInstall(3)