This document describes how to add a new external package to the Condor build. There are a number of elements to this task which are described below:
Before getting into the specifics, here's the 10,000 foot view of how the Condor build system deals with externals:
Understanding the above overview will help make sense of the specific steps needed for modifying the build system to know about and use a new external.
In general, the process of adding a new version of an existing external is very similar to if you're adding a whole new external. However, in any point in this instructions where something extra is required, that will be made clear...
Regarding the name: it should be descriptive, but not too long/verbose. "z" is not good. "zlib-compression-library" isn't either. usually it's pretty obvious. if you have any questions ASK someone else BEFORE you start adding, since it'll eventually require adding a new directory to our repository, and that's impossible to undo...
Regarding the version: ideally, this should be the official version number of the external package as decided by its authors. If we patch a given external, that doesn't change the official version we're basing the package on, and that's what the version number should be.
However, if you want to add new patches to an existing external, you should change the version number and add a new external! We do NOT want to have multiple things which are different code to be using the same version!!!
Again, if you have any questions or are uncertain, just ask.
Finally, the combination of [name]-[version] is often referred to in the build system (and this document) as the package name, and you'll see it listed as [package-name]
Each external package used to build Condor lives in a unique directory as part of the externals directory tree. The basic directory layout of externals is as follows:
externals/
/build
/install
/triggers
/bundles/
/[name]
/[version]
The build directory is a temporary build sandbox, which we'll talk about more later. The install directory is where each external package installs its build output so it can be used by the Condor build. The triggers directory holds the trigger files (mentioned in the overview) that determine if a given external was successfully built. Want to have your Condor workspace rebuild the zlib external? Just remove the externals/triggers/zlib-[version] file and the src/Imakefile will ensure that a top-level "make" will rebuild zlib...
The bundles directory contains subdirectories for each kind of package, and each package directory has subdirectories for each version of that package. For example, at the time of this writing, we've got 5 different versions of the glibc external, each living in their own subdirectory of externals/bundles/glibc.
externals/
/bundles/
/glibc/
/2.1.1
/2.2.2
/2.2.93
/2.3.2
/2.3.2.27.9.7
Inside each version-specific subdirectory, are 2 main things:
Optionally, there may be patch file(s) which include modifications we had to make to the package to get it to work with Condor.
Each of these things are addressed in the following sections...
Setting up the source tarball
Ideally, there's nothing you should need to do to modify the source
tarball of the external package. We want the original, unmodified
source whenever possible. However, the name of the tarball is
important, since the Condor build system itself makes assumptions
about the name so that the build_externals script can untar
the tarball for you (one less thing for your build-script to worry
about for yourself). So, the source tarball must be
named "[name]-[version].tar.gz" (and, needless to say, it must
be a real gzip'ed tar file). For example, "krb5-1.2.7.tar.gz".
Making the build script
When the Condor build is trying to build your external, first it
will create a temporary sandbox build directory. The
[name]-[version].tar.gz will be untarred into the sandbox. Then, the
build_[name]-[version] script will be invoked with the
current working directory set to the sandbox build directory. This
script is responsible for building the external package in whatever
way makes sense. The calling layer assumes the responsibility of
cleaning up the build sandbox. It will also keep track of whether or
not things need to be rebuilt.
Build script environment variables
In addition to being born with the build sandbox directory as the current working directory, the following environment variables will be set (these are literal... no substitution of package name or anything):
$PACKAGE_NAME # the name of this package $PACKAGE_DEBUG # empty if release, '-g' if debug build $PACKAGE_BUILD_DIR # the sandbox build directory $PACKAGE_INSTALL_DIR # where to put the results $EXTERNALS_INSTALL_DIR # full path to root of externals/install $EXTERNALS_CONFIG # full path to config.sh with config variables
$PACKAGE_NAME is the [name]-[version] identifying string for your package.
$PACKAGE_BUILD_DIR is a subdirectory of externals/build, named with the package-name. This is just a temporary sandbox directory, and build_external will remove this directory and all its contents as soon as your build script exits.
$PACKAGE_INSTALL_DIR is a subdirectory of externals/install, named with the package-name as well. This directory won't necessarily exist when your build script is spawned, so your script is responsible for creating this directory in whatever way is appropriate for your package. Most packages don't have to worry about it, since make install takes care of it for you. Some packages need to copy a whole tree to this location, so we don't want to make you rmdir if you don't want it there in the first place. However, the parent of this directory (the directory path stored in $EXTERNALS_INSTALL_DIR) is guaranteed to exist, so you don't need to worry about mkdir -p.
If your build script wants to know things that the Condor build
system determines at run-time (for example, what globus flavor we're
trying to build), it can source the file specified in
$EXTERNALS_CONFIG (details on sourcing this file below).
This is a simple bourne shell syntax file that defines a bunch of
shell variables that hold information that the configure
script discovers. If your external needs to know something that the
configure script figures out but that isn't yet in
config/config.sh, all you have to do is add a new line to
config/config.sh.in to define the variable you need. Also,
note that if you want to pass any of these variables onto the
configure script or build system of your package, you either
have to pass them in as arguments or manually export them yourself as
environment varialbes (by default, you just get shell variables in
your script, not environment variables).
Build script syntax
YOUR BUILD SCRIPT MUST BE PLAIN OLD BOURNE SHELL!!!. Do NOT use any bash syntax, since it won't work on all 15+ Condor platforms. For example, source is not portable across all versions of bourne shell. The correct way to include this file in your build script is to use:
. $EXTERNALS_CONFIG
Similarly, to set an environment variable, you can NOT do this:
export FOO=barYou MUST use:
FOO=bar export FOO
Another shell idiom that does NOT work is using this:
if( ! make ); then blah blah; fiYou MUST use:
make
if [ $? -ne 0 ]
then
blah blah
fi
If your script encounters an error during the build, exit with status 1.
After building, you should run any tests that are available.
If any tests do not pass or any other error occurs, exit with status 2.
After passing tests, you script should install the package into the directory $PACKAGE_INSTALL_DIR in whatever format is customary for that package.
If there is a problem during installation, exit with status 3.
If there is any problem specific to your package, exit with status 10 or
higher. Status 4-9 is reserved for future use. You can only exit with
status 0 if everything is fully installed and working (to the best of your
knowledge).
Build script example
Here is an example build_generic_package, which would build most things that follow the common tar and 'configure / make / make test / make install' convention:
#!/bin/sh
############# build_generic_package
cd $PACKAGE_NAME/src
./configure --prefix=$PACKAGE_INSTALL_DIR --with-ccopts=$PACKAGE_DEBUG
make
if [ $? -ne 0 ]
then
echo "make failed"
exit 1
fi
make test
if [ $? -ne 0 ]
then
echo "test failed"
exit 2
fi
make install
if [ $? -ne 0 ]
then
echo "install failed"
exit 3
fi
exit 0
############# end of build_generic_package
If your external needs to be patched, the preferred method for dealing with it is to create patch files, and put those patches into the version-specific subdirectory. Then, the build-script for the package can invoke patch as needed. An example to look at would be the krb5-1.2.5 external (externals/bundles/krb5/1.2.5/)
Again, if you want to add additional patches to an existing external, you MUST make an entirely new external package with a different version number (e.g. something like krb5-1.2.5.pl1) so that we can tell the difference between the two versions. This is a little wasteful of space, unfortunately, but there's no way around that at this time.
Once your package is setup in the externals tree and the build
script ready, you've got to tell the Condor build system about the new
package. There are a few separate places that this needs to happen.
Changing autoconf-related stuff
The first step in integrating a new external with the build system is to modify src/configure.ac, the input file for autoconf. Near the bottom of this file, there's a section of tests that determine what version of each external we want to use. The section begins with the following code block:
############################################################ # What versions of what externals do we need ############################################################ AC_MSG_NOTICE([determining versions of external packages])
Some of the "tests" are trivial, they just define a version to use directly. Other tests do something more fancy, like choose a version depending on the platform we're on. Ultimately, autoconf is just a fancy way of using M4 macros to make a giant bourne shell script. If you following the existing syntax and examples already in this section, you should be in good shape. If you have trouble, either check out the autoconf documentation (for example autoconf 2.57). The important thing is that once you know what version of the external you need, that you call our special autoconf macro, CHECK_EXTERNAL(), which handles everything else for you. For example, here's a simple case, zlib:
CHECK_EXTERNAL([zlib],[1.1.3], [soft])This handles the following tasks for you:
If you're just changing the version of an existing external, that's probably all you'll have to do to the autoconf stuff, and you can skip right to the discussion of CVS changes. However, if you're adding a whole new external package, there are a few more steps (both for autoconf and imake, so read on...
To add a whole new kind of external, you've got to understand a bit about that [soft] argument (the requirement level), modify config/externals.cf.in and config/config.sh.in to hold the results of the new test you added in src/configure.ac. Again, if you just edit the files and follow the existing examples, you'll probably be in fine shape. But, for the sake of complete docs, I'll explain in a little more detail here:
There are three requirement levels, and they determine how dependent Condor is on an external. The levels are soft, hard, and optional. The soft level is the most common and is likely what you need to specify. It means that Condor can compile and operate just fine without the external. When configure is run it will look for soft requirements, but will only give a warning if they are not available. This is in contrast to hard requirements, which are always required. Condor either will not compile or run without them. They MUST be present. Not being present will cause configure to fail. You want to avoid adding hard externals to Condor. The third level, optional, is just as uncommon as hard, if not more. It operates almost exactly as soft with one exception: there is a --with-soft-is-hard option that can be given to configure to treat all soft requirements as if they were hard requirements. This option does not change how optional externals are treated. So, you really want your external to be a soft, unless you have a really good reason for it not to be.
The most important thing is to define a new make variable to hold the version of the external you added. For example, here's what happens for zlib:
EXT_ZLIB_VERSION = @ext_zlib_version@
The rest of the build system that needs to know how to find zlib can now use this variable. Almost always, what we really care about is the installed output of the external build. This is a common way to deal with that:
ZLIB_DIR = $(EXT_INSTALL)/$(EXT_ZLIB_VERSION) ZLIB_LIB = $(ZLIB_DIR)/lib ZLIB_INC = $(ZLIB_DIR)/includeObviously, the details depend on the specifics of a given package, but in general, something like the above is what you want to do. This way, we have the full path to the lib and include directories for the external, and each of those make variables can be used in regular Condor imake input files so that the Condor build can use the external.
... GLOBUS_FLAVOR=... EXT_GLOBUS_VERSION=... HAS_STATIC=... ...Inside build_gahp-1.0.10, we use the following code:
. $EXTERNALS_CONFIG FLAVOR="--with-flavor=$GLOBUS_FLAVOR" GLOBUS="--with-globus=$EXTERNALS_INSTALL_DIR/$EXT_GLOBUS_VERSION" STATIC_BUILD="--with-static=$HAS_STATIC" cd $PACKAGE_BUILD_DIR/$PACKAGE_NAME/ ./configure --prefix=$PACKAGE_INSTALL_DIR $GLOBUS $FLAVOR $STATIC_BUILD
NOTE: if you're just changing the version of an existing external, you probably don't have to mess with any imake stuff at all.
Once autoconf knows all about your new external, and the various make variables have been set in the files in config, there are a few minor changes to the imake input files themselves that need to be made so the Condor build knows about the external. In particular, the src/Imakefile needs to know about your external.
To do this, all you have to do is add a new ext_target to the file. This magic imake rule handles all the details of ensuring the Condor build depends on your external, and that externals/build_external is invoked to build your external at the appropriate time. This target takes two arguments, the package name (which should be held in the make variable EXT_[NAME]_VERSION), and any externals your package depends on.
Here's the boring zlib example. There, nothing to it, since we always want this external built, and it doesn't depend on anything else:
ext_target(EXT_ZLIB_VERSION,$(NULL))
Here's the complicated globus example. It depends on the GPT external, and we only want to build it if the HAVE_EXT_GLOBUS imake #define is set, which happens when configure finds the globus external:
#if HAVE_EXT_GLOBUS ext_target(EXT_GLOBUS_VERSION,$(EXT_TRIGGER)/$(EXT_GPT_VERSION)) ... #endifNote the use of $(EXT_TRIGGER). That's how imake (and therefore, make) know a given external was successfully built. $(EXT_TRIGGER) holds the full path to the triggers directory (described above). Each trigger file is just named with the package name. So, by making the globus external depend on $(EXT_TRIGGER)/$(EXT_GPT_VERSION), we ensure that GPT is built before Globus.
If your external depends on multiple other externals, all you have to do is include multiple trigger files (separated by spaces) in the second argument to ext_target. For example:
ext_target(EXT_FOO_VERSION,$(EXT_TRIGGER)/$(EXT_BAR_VERSION) $(EXT_TRIGGER)/$(EXT_BAZ_VERSION))
Finally, there's the tricky subject of exactly how the Condor imake system should use your external and integrate it with the rest of the Condor source. Eventually we'll have a better answer for that question here. For now, if it's not totally obvious, just talk to someone else on the staff and try to come up with something good. When in doubt, ask Derek.
Once all this is done, you're in a position to fully test your new external with a Condor build. You'll have to re-run autoconf to generate src/configure and re-run the src/configure script itself. After that, a top-level make inside src should be all you need to see your external package built. Once your external build is working and the Condor source sees and uses the new external, you're ready to commit your changes to CVS...
This is mostly obvious, boring stuff, and I assume you know how to
use CVS. I'm just including this section so that you don't forget any
of these final steps...
Checking it into the externals tree
The externals tree lives on the trunk of the Condor CVS
repository. It is never branched, merged, etc. So, all externals are
in theory visible from all Condor CVS branches. When you add your new
directory into externals/bundles/[name]/[version] you should
ensure that you're committing your new files to the trunk. You should
add the directory, then do a cvs add to the source tarball
(cvs already knows files that end in .gz are binary, so you don't have
to worry about that), the build script, and any patches you've made.
Once that's done, you can cvs commit as normal.
Checking in Condor build system changes
The changes you made to src/configure.ac,
src/Imakefile (if any), and any changes to files in
config must be committed to a specific Condor CVS
branch. Fundamentally, it's the fact that
src/configure.ac is branched and merged with the rest of the
Condor source that enables us to know exactly what versions of each
external were used for a given version of Condor. So, when you're
committing all those changes to the build system (and to the rest of
the Condor source to take advantage of the new external), you must do
so to a real branch. In fact, most of the time, you'll want to
create a new branch off the main development branch at the time to
deal with adding your new external. That way, we can test building
your new external and all related changes on all our platforms,
without breaking the build on the main release branch at the time.
Adding it to the appropriate CVS modules
Finally (and this applies to both a new version of an existing
external and adding a whole new kind of external), you should add your
new external to the appropriate CVS module(s). Even though your new
external lives on the trunk and is therefore visible by all Condor
branches, it doesn't mean we actually want to see your external
everywhere.
To solve this issue, we rely on a number of CVS modules to select the versions of the externals we care about on each main Condor CVS branch. For example, V6_6_EXT holds all the externals we need for building the V6_6-branch of Condor. So, if you added a new external to the V6_7-branch, you'd want to add another line to the V6_7_EXT CVS module.
To modify a CVS module, all you have to do is this:
% cd /tmp % cvs co CVSROOT/modules %As always, if you open up the file and look, the syntax should be pretty obvious. The main thing is that you remember to do this step at all, and that you add your external to the right module(s).CVSROOT/modules % cvs commit CVSROOT/modules
Things might get a little tricky if you're replacing an old version of a given external with a new one. In that case, be sure you don't break any of the version-specific historical modules (e.g. V6_6_2_EXT) when you want to remove the old version. In this case, V6_6_2_EXT is defined relative to V6_6_COMMON_EXT. So, if you want to remove externals/bundles/globus/2.2.4 from the V6_6_3_EXT module, you'll probably have to remove globus/2.2.4 from V6_6_COMMON_EXT and manually add it back to all the version-specific modules that used to include it. An example of this is that we changed the version of the gahp external between V6_6_0 and V6_6_1, so we had to remove the gahp from V6_6_COMMON_EXT since the same version of it was no longer common to all the 6.6.x modules.
To update the externals tree, just do this:
% cd /p/condor/workspaces % cvs co externals/bundles
Once that's been updated, all you have to do is start a build of the Condor source (from the branch where you checked in your build system changes for the new external) on each kind of machine we care about. Basically, any platform with an @sys directory in /p/condor/workspaces/externals/sys is what you'd need to worry about.
Just make sure the build on each platform uses /p/condor/workspaces/externals for the externals. If you do not check out a local copy of externals into either your source or build workspaces, our configure script will use the tree in AFS by default. Otherwise, you can always use this:
% ./configure --with-externals=/p/condor/workspaces/externalsOnce you start the build, the externals will be built first. Assuming everyone else is following these directions, the only external that will need to be built is the one you just added. This will ensure that all the developers using this pre-built tree won't have any problems as a result of your new external.