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 --priority PRIORITY will be set to a number
124 --mainpackage MAINPACKAGE controls which package is treated as the
125 main package to act on
126 --name NAME a name to use for installed files, instead of
128 --error-handler ERROR_HANDLER a function to call on error
130 Any additional command line parameters that do not start with "-" will be
131 ignored, and you can access them later just as you normally would.
136 The following keys are also set in the %dh hash when you call init():
138 MAINPACKAGE the name of the first binary package listed in
140 FIRSTPACKAGE the first package we were instructed to act on. This package
141 typically gets special treatment; additional arguments
142 specified on the command line may effect it.
147 Dh_Lib.pm also contains a number of functions you may find useful.
150 Pass this function an array that is a
151 shell command. It will run the command (unless $dh{NO_ACT} is set), and
152 if $dh{VERBOSE} is set, it will also output the command to stdout. You
153 should use this function for almost all commands your program performs
154 that manipulate files in the package build directories.
155 complex_doit($command)
156 Pass this function a string that is a shell command, it will run it
157 similarly to how doit() does. You can pass more complicated commands
158 to this (ie, commands involving piping redirection), however, you
159 have to worry about things like escaping shell metacharacters.
160 verbose_print($message)
161 Pass this command a string, and it will echo it if $dh{VERBOSE} is set.
163 Pass this command a string, it will output it to standard error and
166 Pass this command a string, and it will output it to standard error
167 as a warning message.
169 Pass this command the name of a binary package, it will return the
170 name of the tmp directory that will be used as this package's
171 package build directory. Typically, this will be "debian/package".
173 Pass this command a number, and if the current compatibility level
174 is less than or equal to that number, it will return true.
175 Looks at DH_COMPAT to get the compatibility level.
176 pkgfile($package, $basename)
177 Pass this command the name of a binary package, and the base name of a
178 file, and it will return the actual filename to use. This is used
179 for allowing debhelper programs to have configuration files in the
180 debian/ directory, so there can be one config file per binary
181 package. The convention is that the files are named
182 debian/package.filename, and debian/filename is also allowable for
183 the $dh{MAINPACKAGE}. If the file does not exist, nothing is returned.
185 Pass this command the name of a binary package, and it will return
186 the name to prefix to files in debian/ for this package. For the
187 $dh{MAINPACKAGE}, it returns nothing (there is no prefix), for the other
188 packages, it returns "package.".
190 Pass this command the name of a package, it returns 1 if the package
191 is a native debian package.
192 As a side effect, $dh{VERSION} is set to the version number of the
194 autoscript($package, $scriptname, $snippetname, $sedcommands)
196 - binary package to be affected
198 - filename of snippet
199 - sed commands to run on the snippet. Ie, s/#PACKAGE#/$PACKAGE/
200 (optional) Note: Passed to the shell inside double quotes.
201 This command automatically adds shell script snippets to a debian
202 maintainer script (like the postinst or prerm).
203 Note that in v6 mode and up, the snippets are added in reverse
204 order for the removal scripts.
206 Return directory part of pathname.
208 Return base of pathname,
209 addsubstvar($package, $substvar, $deppackage, $verinfo, $remove)
210 This function adds a dependency on some package to the specified
211 substvar in a package's substvar's file. It needs all these
213 - binary package that gets the item
214 - name of the substvar to add the item to
215 - the package that will be depended on
216 - version info for the package (optional) (ie: ">= 1.1")
217 - if this last parameter is passed, the thing that would be added
218 is removed instead. This can be useful to ensure that a debhelper
219 command is idempotent. (However, we generally don't bother,
220 and rely on the user calling dh_prep.) Note that without this
221 parameter, if you call the function twice with the same values it
222 will only add one item to the substvars file.
223 delsubstvar($package, $substvar)
224 This function removes the entire line for the substvar from the
225 package's shlibs file.
226 excludefile($filename)
227 This function returns true if -X has been used to ask for the file
230 Returns true if the package is marked as a udeb in the control
232 udeb_filename($package)
233 Returns the filename of the udeb package.
235 Returns a list of packages in the control file.
236 Pass "arch" or "indep" to specify arch-dependent or
237 -independent. If nothing is specified, returns all
238 packages (including packages that are not built
239 for this architecture). Pass "both" to get the union
240 of "arch" and "indep" packages.
241 As a side effect, populates %package_arches and %package_types with
242 the types of all packages (not only those returned).
244 Prevent logging the program's successful finish to
245 debian/*debhelper.log
246 load_log($package, $hashref)
247 Loads the log file for the given package and returns a list of
249 (Passing a hashref also causes it to populate the hash.)
250 write_log($cmd, $package ...)
251 Writes the log files for the specified package(s), adding
257 The dh(1) command has a --with <addon> parameter that ca be used to load
258 a sequence addon module named Debian::Debhelper::Sequence::<addon>.
259 These modules can add/remove commands to the dh command sequences, by
260 calling some functions from Dh_Lib:
262 insert_before($existing_command, $new_command)
263 Insert $new_command in sequences before $existing_command
265 insert_after($existing_command, $new_command)
266 Insert $new_command in sequences after $existing_command
268 remove_command($existing_command)
269 Remove $existing_command from the list of commands to run
272 add_command($new_command, $sequence)
273 Add $new_command to the beginning of the specified sequence.
274 If the sequence does not exist, it will be created.
276 add_command_options($command, $opt1, $opt2, ...)
277 Append $opt1, $opt2 etc. to the list of additional options which
278 dh passes when running the specified $command. These options are
279 not relayed to debhelper commands called via $command override.
281 remove_command_options($command)
282 Clear all additional $command options previously added with
283 add_command_options().
285 remove_command_options($command, $opt1, $opt2, ...)
286 Remove $opt1, $opt2 etc. from the list of additional options which
287 dh passes when running the specified $command.
292 The dh_auto_* commands are frontends that use debhelper buildsystem
293 classes. These classes have names like Debian::Debhelper::Buildsystem::foo,
294 and are derived from Debian::Debhelper::Buildsystem, or other, related
297 A buildsystem class needs to inherit or define these methods: DESCRIPTION,
298 check_auto_buildable, configure, build, test, install, clean. See the comments
299 inside Debian::Debhelper::Buildsystem for details. Note that this interface
300 is still subject to change.
302 Note that third-party buildsystems will not automatically be used by default,
303 but can be forced to be used via the --buildsystem parameter.
305 -- Joey Hess <joeyh@debian.org>