1 This file documents things you should know to write a new debhelper program.
2 Any program with a name that begins with dh_ should conform to these
3 guidelines (with the historical exception of dh_make).
8 There are lots of debhelper commands. To make the learning curve shallower,
9 I want them all to behave in a standard manner:
11 All debhelper programs have names beginning with "dh_". This is so we don't
12 pollute the name space too much.
14 Debhelper programs should never output anything to standard output except
15 error messages, important warnings, and the actual commands they run that
16 modify files under debian/ (this last only if they are passed -v, and if you
17 output the commands, you should indent them with 1 tab). This is so we don't
18 have a lot of noise output when all the debhelper commands in a debian/rules
19 are run, so the important stuff is clearly visible.
21 Debhelper programs should accept all options listed in the "SHARED
22 DEBHELPER OPTIONS" section of debhelper(7), including any long forms of
23 these options, like --verbose . If necessary, the options may be ignored.
25 If debhelper commands need config files, they should use
26 debian/package.filename as the name of the config file (replace filename
27 with whatever your command wants), and debian/filename should also be
28 checked for config information for the first binary package in
29 debian/control. Also, debhelper commands should accept the same sort of
30 information that appears in the config files, on their command lines, if
31 possible, and apply that information to the first package they act on.
32 The config file format should be as simple as possible, generally just a
33 list of files to act on.
35 Debhelper programs should never modify the debian/postinst, debian/prerm,
36 etc scripts. Instead, they can add lines to debian/postinst.debhelper, etc.
37 The autoscript() function (see below) is one easy way to do this.
38 dh_installdeb is an exception, it will run after the other commands and
39 merge these modifications into the actual postinst scripts.
41 In general, files named debian/*.debhelper are internal to debhelper, and
42 their existence or use should not be relied on by external programs such as
43 the build process of a package. These files will be deleted by dh_clean.
45 Debhelper programs should default to doing exactly what policy says to do.
47 There are always exceptions. Just ask me.
52 Dh_Lib is the library used by all debhelper programs to parse their
53 arguments and set some useful variables. It's not mandatory that your
54 program use Dh_Lib.pm, but it will make it a lot easier to keep it in sync
55 with the rest of debhelper if it does, so this is highly encouraged.
59 use Debian::Debhelper::Dh_Lib
62 The init() function causes Dh_lib to parse the command line and do some other
68 All debhelper programs should respond to certain arguments, such as -v, -i,
69 -a, and -p. To help you make this work right, Dh_Lib.pm handles argument
70 processing. Just call init().
72 You can add support for additional options to your command by passing an
73 options hash to init(). The hash is then passed on the Getopt::Long to
74 parse the command line options. For example, to add a --foo option, which
77 init(options => { foo => \$dh{FOO} });
79 After argument processing, some global variables are used to hold the
80 results; programs can use them later. These variables are elements of the
83 switch variable description
84 -v VERBOSE should the program verbosely output what it is
86 --no-act NO_ACT should the program not actually do anything?
87 -i,-a,-p,-N DOPACKAGES a space delimited list of the binary packages
88 to act on (in Dh_Lib.pm, this is an array)
89 -i DOINDEP set if we're acting on binary independent
91 -a DOARCH set if we're acting on binary dependent
93 -n NOSCRIPTS if set, do not make any modifications to the
94 package's postinst, postrm, etc scripts.
95 -o ONLYSCRIPTS if set, only make modifications to the
96 package's scripts, but don't look for or
97 install associated files.
98 -X EXCLUDE exclude a something from processing (you
99 decide what this means for your program)
101 -X EXCLUDE_FIND same as EXCLUDE, except all items are put
102 into a string in a way that they will make
103 find find them. (Use ! in front to negate
104 that, of course) Note that this should
105 only be used inside complex_doit(), not in
107 -d D_FLAG you decide what this means to your program
108 -k K_FLAG used to turn on keeping of something
109 -P TMPDIR package build directory (implies only one
110 package is being acted on)
111 -u U_PARAMS will be set to a string, that is typically
112 parameters your program passes on to some
113 other program. (This is an array)
114 -V V_FLAG will be set to a string, you decide what it
115 means to your program
116 -V V_FLAG_SET will be 1 if -V was specified, even if no
117 parameters were passed along with the -V
118 -A PARAMS_ALL generally means that additional command line
119 parameters passed to the program (other than
120 those processed here), will apply to all
121 binary packages the program acts on, not just
123 --sourcedir SOURCEDIR will be set to a string
124 --destdir DESTDIR will be set to a string
125 --priority PRIORITY will be set to a number
126 --mainpackage MAINPACKAGE controls which package is treated as the
127 main package to act on
128 --name NAME a name to use for installed files, instead of
130 --error-handler ERROR_HANDLER a function to call on error
132 Any additional command line parameters that do not start with "-" will be
133 ignored, and you can access them later just as you normally would.
138 The following keys are also set in the %dh hash when you call init():
140 MAINPACKAGE the name of the first binary package listed in
142 FIRSTPACKAGE the first package we were instructed to act on. This package
143 typically gets special treatment; additional arguments
144 specified on the command line may effect it.
149 Dh_Lib.pm also contains a number of functions you may find useful.
152 Pass this function an array that is a
153 shell command. It will run the command (unless $dh{NO_ACT} is set), and
154 if $dh{VERBOSE} is set, it will also output the command to stdout. You
155 should use this function for almost all commands your program performs
156 that manipulate files in the package build directories.
157 complex_doit($command)
158 Pass this function a string that is a shell command, it will run it
159 similarly to how doit() does. You can pass more complicated commands
160 to this (ie, commands involving piping redirection), however, you
161 have to worry about things like escaping shell metacharacters.
162 verbose_print($message)
163 Pass this command a string, and it will echo it if $dh{VERBOSE} is set.
165 Pass this command a string, it will output it to standard error and
168 Pass this command a string, and it will output it to standard error
169 as a warning message.
171 Pass this command the name of a binary package, it will return the
172 name of the tmp directory that will be used as this package's
173 package build directory. Typically, this will be "debian/package".
175 Pass this command a number, and if the current compatibility level
176 is less than or equal to that number, it will return true.
177 Looks at DH_COMPAT to get the compatibility level.
178 pkgfile($package, $basename)
179 Pass this command the name of a binary package, and the base name of a
180 file, and it will return the actual filename to use. This is used
181 for allowing debhelper programs to have configuration files in the
182 debian/ directory, so there can be one config file per binary
183 package. The convention is that the files are named
184 debian/package.filename, and debian/filename is also allowable for
185 the $dh{MAINPACKAGE}. If the file does not exist, nothing is returned.
187 Pass this command the name of a binary package, and it will return
188 the name to prefix to files in debian/ for this package. For the
189 $dh{MAINPACKAGE}, it returns nothing (there is no prefix), for the other
190 packages, it returns "package.".
192 Pass this command the name of a package, it returns 1 if the package
193 is a native debian package.
194 As a side effect, $dh{VERSION} is set to the version number of the
196 autoscript($package, $scriptname, $snippetname, $sedcommands)
198 - binary package to be affected
200 - filename of snippet
201 - sed commands to run on the snippet. Ie, s/#PACKAGE#/$PACKAGE/
203 This command automatically adds shell script snippets to a debian
204 maintainer script (like the postinst or prerm).
205 Note that in v6 mode and up, the snippets are added in reverse
206 order for the removal scripts.
208 Return directory part of pathname.
210 Return base of pathname,
211 addsubstvar($package, $substvar, $deppackage, $verinfo, $remove)
212 This function adds a dependency on some package to the specified
213 substvar in a package's substvar's file. It needs all these
215 - binary package that gets the item
216 - name of the substvar to add the item to
217 - the package that will be depended on
218 - version info for the package (optional) (ie: ">= 1.1")
219 - if this last parameter is passed, the thing that would be added
220 is removed instead. This can be useful to ensure that a debhelper
221 command is idempotent. Note that without this parameter, if you
222 call the function twice with the same values it will only add one
223 item to the substvars file.
224 delsubstvar($package, $substvar)
225 This function removes the entire line for the substvar from the
226 package's shlibs file.
227 excludefile($filename)
228 This function returns true if -X has been used to ask for the file
231 Returns true if the package is marked as a udeb in the control
233 udeb_filename($package)
234 Returns the filename of the udeb package.
236 Returns a list of packages in the control file.
237 Must pass "arch" or "indep" or "same" to specify arch-dependent or
238 -independent or same arch packages. If nothing is specified, returns all
240 As a side effect, populates %package_arches and %package_types with
241 the types of all packages (not only those returned).
243 Prevent logging the program's successful finish to
244 debian/*debhelper.log
245 load_log($package, $hashref)
246 Loads the log file for the given package and returns a list of
248 (Passing a hashref also causes it to populate the hash.)
249 write_log($cmd, $package ...)
250 Writes the log files for the specified package(s), adding
256 The dh(1) command has a --with <addon> parameter that ca be used to load
257 a sequence addon module named Debian::Debhelper::Sequence::<addon>.
258 These modules can add/remove commands to the dh command sequences, by
259 calling some functions from Dh_Lib:
261 insert_before($existing_command, $new_command)
262 Insert $new_command in sequences before $existing_command
264 insert_after($existing_command, $new_command)
265 Insert $new_command in sequences after $existing_command
267 remove_command($existing_command)
268 Remove $existing_command from the list of commands to run.
273 The dh_auto_* commands are frontends that use debhelper buildsystem
274 classes. These classes have names like Debian::Debhelper::Buildsystem::foo,
275 and are derived from Debian::Debhelper::Buildsystem, or other, related
278 A buildsystem class needs to inherit or define these methods: DESCRIPTION,
279 check_auto_buildable, build, test, install, clean. See the comments
280 inside Debian::Debhelper::Buildsystem for details.
282 Note that third-party buildsystems will not automatically be used by default,
283 but can be forced to be used via the --buildsystem parameter.
285 -- Joey Hess <joeyh@debian.org>