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The CONFIGURE script is sourced during a cast, after DETAILS and before DEPENDS and CONFLICTS. It is used to take care of more complex spells for which extra information must be gathered and stored. This can be needed when there are optional ./configure switches that don't require any extra spells, or for doing extra things in the BUILD script. The query can be made in the CONFIGURE and then the flags stored can be used in any of the spell scripts.
Sorcery provides a way to store and later re-store environment variables between different spell scripts. The environment variable you want to persist must be marked by function persistent_add:
persistent_add VAR BLAH SPELL_OPTION
This way you marked the three variables so that they will be persisted.
Moreover Sorcery gives you tools for querying user for information. The functions are provided for your convenience:
config_query_multi.function file found in the root of some grimoires)These functions do have three parameters:
Example:
config_query RMRF "Perform rm -rf / ?" y config_query_string NAME "What is your name ?" $USER config_query_list MTA "Which mta would you like to use ?" qmail sendmail postfix config_query_option SPELL_OPTION "Use X ?" y "--with-x" "--without-x" config_query_multi SOMETHING "What do you want?" all none something1 something2
config_query_option is a bit different, it does not overwrite content of $SPELL_OPTION, rather the result is appended to it.
config_query_multi is different from config_query_list in that it makes available multiple options instead of just one.
To use it one has to add . "$GRIMOIRE/config_query_multi.function" before calling it.
Note a dot at the beginning.
All config_query* functions also mark the variable to be persistent automatically, and if that variable allready exists it won't ask again, just print out the answer from last query. If it isn't apparent then you should know that if you change the config_query* call you'll also want to change the variable name.
For more examples and functions look into /var/lib/sorcery/modules/libapi
In order to make actual use of user specified options via listed above config_query* functions in CONFIGURE file we have to pass the saved values of the variables to a spell BUILD file. This is done by declaring a custom variable in CONFIGURE file and then specifying this variable name in BUILD file.
The following example shows what is required to be done:
Example, "irssi" spell – CONFIGURE file:
config_query_option IRSSI_OPTS "build with irssi-bot" n \
"--with-bot" "--without-bot" &&
config_query_option IRSSI_OPTS \
"build with irssi-proxy (to use irssi as a bouncer)" n \
"--with-proxy" "--without-proxy"IRSSI_OPTS is the custom variable that stores answers a user gives us, e.g. --with-bot or --without-bot. We then need to create a BUILD file and put in there the stored user answers this way:
Example, "irssi" spell – BUILD file:
OPTS="$IRSSI_OPTS $OPTS" && default_build
OPTS="" contains both $IRSSI_OPTS, a custom variable that we declared in CONFIGURE file, and a mandatory $OPTS variable that is always expected to be placed after all of the custom variables. $OPTS is an internal sorcery variable holding some common flags and the ones from the dependencies.
The scenario described above provides a method that lets us ask a user some configuration related questions, obtain and store answers and then be able to apply changes to a spell configuration according to a user's instructions.