Conda recipe generator for the LSST Software Stack

Overview

This repository contains conda-lsst, a utility that generates Conda recipes for LSST stack packages. The recipes are generated using the information stored in EUPS, the package manager that LSST uses internally.

conda-lsst also provides a convenient mechanism to build the generated recipes in proper order, and to upload the resulting binaries to a remote web server from where they will be installable using conda install.

You only need this code if you wish to create and distribute your own build of the LSST stack; conda-lsst is not needed to just use the LSST codes. If all you want is to install the LSST stack, skip to the Installing section.

This code is beta quality; it is expected to work on OS X and Linux.

Prerequisites

You need at least Miniconda with conda-build, jinja2, requests, and sqlalchemy packages installed, as well as the requests_file python module (install with pip install requests_file). You will also need to build and install the git-lfs and lsst-git-lfs-config conda packages using the recipes found in etc/recipes directory. For your convenience, there's a script, ./bin/bootstrap.sh, that when run:

bash ./bin/bootstrap.sh

will install all of these for you. Miniconda will be installed into a subdirectory named miniconda.

Docker containerized builds (Linux)

If you have docker, and want conda package builds to happein within a CentOS 5 docker container (recommended, for maximum binary compatibility), run:

cd docker
make

to create the necessary docker image.

Once make is run, it will print out the instructions on how to set the REBUILD_RECIPES_IN_CONTAINER environmental variable and make the new container known to rebuild.sh.

The rebuild.sh script that conda lsst make-recipes checks for the contents of $REBUILD_RECIPES_IN_CONTAINED variable and uses it as a driver for conda build (if present). It's best to export this variable from your .bashrc.

Generating Conda recipes, and building the packages

To generate all packages and upload them to a remote service, run someting like the following:

# Add conda-lsst to PATH. This will allow you to call it as `conda lsst`
export PATH="$PWD/bin:$PATH"

# Tell conda where the channel we'll be uploading to is
conda config --add channels http://eupsforge.net/conda/dev

# Build conda packages for LSST codes (the recipes will be stored in the `recipes` subdirectory)
conda lsst make-recipes build:b1852 lsst_distrib lsst_sims --build

# Upload to the 'dev' channel
conda lsst upload

Note: conda-lsst is smart about not rebuilding packages that have already been built.

Build logs are stored in recipes/<packagename>/_build.log. Failed builds can be debugged by changing into the source directory (usually .../conda-bld/work) and running ./_build.sh <eupspkg_verb> where the verb is typically build.

The first parameter passed to conda lsst make-recipes is an lsst-build generated manifest. You may be familar with these as manifest.txt files that lsstsw generates in its build directory. For "official" builds, they're also stored in the canonical versiondb by the lsstsw's rebuild script when run on lsst-dev as lsstsw.

To find out which build manifests (as stored in the canonical versiondb contain a particular product, use the what-builds utility. For example:

$ what-builds lsst_apps | tail
lsst_apps b2005
lsst_apps b2007
lsst_apps b2010
lsst_apps b2012
lsst_apps b2014
lsst_apps b2015
lsst_apps b2017
lsst_apps b2018
lsst_apps b2020
lsst_apps b2021

Installing and Running Conda-delivered LSST softwre

See this gist or the video tutorial.

The binaries are currently being built for 64 bit Linux (any variant newer than RHEL 6) and OS X (10.9 or later). See here for more on binary compatibility.

Technical Details

Package Management: EUPS and Conda

LSST code base consists of more than a hundred packages (largely written in C++ and Python) that depend on each other at build and run time. LSST natively uses EUPS as the package manager (EUPS preferst the term product). EUPS provides a way to record dependencies (through so-called "table files", stored in the ups/ subdirectory of each package), as well as a uniform mechanism to build code that the packages contain irrespective of their internal build system. The latter is known as eupspkg and is described in some detail in the docstring of the eupspkg.py EUPS module. EUPS also provides a facility to distribute code in source form, but it does not have a facility do distribute binaries.

Conda is a package manager written for the Anaconda Python distribution. It has support for building and distribution of binaries: given a recipe -- a shell script that contains commands needed to build the binary, plus some metadata -- the conda-build utility will build the source and tarball it into a "conda package" (physically, a .tar.bz2 file). When uploaded to a specially formatted web-accessible directory (or a hosted service such as anaconda.org), these binary packages can then be installed by the user using the conda install command.

The way we "marry" EUPS and Conda is by a) building EUPS itself as a Conda package, and b) distributing pre-built EUPS products as Conda packages themselves. We therefore primarily utilize Conda as a convenient binary packaging and distribution mechanism; the products themselves still need to be setup-ed using the usual EUPS commands, but the eups distrib install step (which would've built them from source) is now replaced by a simple conda install (which simply unpacks the binary). We also make EUPS itself a dependency of all products: running conda install lsst-distrib will now install both the LSST stack and EUPS itself (thus obviating the need for a separate newinstall.sh script).

The code: conda-lsst utility

The conda-lsst script uses the package dependency information extracted from EUPS, and the eupspkg build system, to generate conda recipes that build LSST codes for a specific release. It also generates a script to build those recipes (in dependency-sorted order), as well as provies a convenient upload utility to upload the built binaries to a package repository.

This section describes technical details and design consideration that went into the code. The basic instructions on how to run it are above.

Overview: what happens when you run conda lsst build

• conda lsst make-recipes reads the list of all products, their versions, and their dependencies from the manifest file (the first argument). The remaining arguments list the EUPS names of the products to be turned into conda packages. Only "top level" products needs to be specified -- conda-lsst will traverse the dependency tree and process all dependencies as necessary.

• The list of products will be topologically sorted and a recipe will be created in recipes subdirectory for each one that needs to be built.

• Of all channels known to conda build, those matching our_channel_regex in config.yaml will be searched for packages with an identical recipe. If one is found, that means the package has already been built and doesn't need to be rebuilt once again (in which case a '.done' file will be placed into the particular product's recipe directory). N.b.: the actual lookup is sped up by hashing and using a database (see below).

• If --build is given on the command line, conda lsst make-recipes will run conda build on each recipe, to build the packages. The results are stored in $CONDA_ROOT/conda-bld/<platform>/ directory (where platform is typically osx-64 or linux-64, depending on your machine).

• The resulting packages can be uploaded to a remote repository using the conda lsst upload command. It uses either scp or rsync to upload the results to the destination server.

Inputs

We don't use EUPS directly to extract the dependency information (though we could!), but instead use the manifest.txt files generated by lsstsw (the backend machinery for LSST's CI system).

A manifest.txt file lists all products, EUPS versions, dependencies, and git SHA1s for all products in a "build" (one run of buildbot). Using a manifest.txt file as input allows us to generate binary Conda packages for any given build.

Subsets of the build can also be generated by providing a list of top-level packages on the command line (e.g., very useful when debugging, as one doesn't need to repeat a whole build for a quick test).

For convenience, given a build tag, one can pull the manifest.txt directly from versiondb directory where they are kept. That lets you do things such as:

conda lsst make-recipes build:b1497 wcslib

Tuning the recipe generation: config.yaml and ~/.condalsstrc

Recipe generation is controlled by entries in config.yaml file. They control virtually all aspects of recipe generation, from injecting missing system dependencies, to defining the output directories and default destination servers to upload to. Refer to comments in config.yaml for more.

Local overrides: ~/.condalsstrc

The settings from condig.yaml can be overridden by keys in ~/condalsstrc. For example, here's what I (mjuric) have in my ~/condalsstrc:

$ cat ~/.condalsstrc
our_channel_regex: '^(?:https?://conda.lsst.mjuric.org/)(.+?)/?$'

upload:
  server:    'centos@conda.lsst.mjuric.org'
  dir_base:  '/var/www/html'
  conda:     'conda'

Conda-packaged EUPS

Conda-packaged EUPS, when unpacked by conda install, is placed into:

$ROOT/opt/eups/

and is configured to store its database (ups_db) information in $ROOT/var/opt/eups/. $ROOT above refers to the root of the Conda environment you're installing into.

We've chosen not to install the EUPS binary (eups) into the global $ROOT/bin/ directory (that is on the users' path). This is because EUPS needs to be correctly initialized before use, and it's likely users would forget to do this. Instead, we install a dummy eups and setup scripts there that remind the users of the need to initialize EUPS before continuing.

The initialization is typically done by source-ing the setups.sh script from its bin/ directory (this is the majority of what loadLSST.sh does). The conda package links those scripts into the global $ROOT/bin/ directory, but prefixed with eups-. Therefore, to initialize EUPS, you need to run:

source eups-setups.sh

(or .csh, .zsh, etc., depending on your shell). Note that it's not necessary to specify the full path to eups-setups.sh -- scripts to be sourced are looked up on $PATH.

For details, see the recipe in etc/recipes/eups.

Conda-packaged EUPS is fully functional. You can use it to install additional EUPS products (for example, with eups distrib install), add tags, etc. We only recommend against using it to remove existing products installed through conda.

Conda-packaged LSST products

The binaries produced by generated recipes unpack into:

$ROOT/opt/lsst/<product>/<version>/

directory, where product is the EUPS product name and the version is the EUPS version (note: these can be different from the Conda names and versions).

Their EUPS information (.version and .chain files) unpacks itself into $ROOT/var/opt/eups/ups_db. Therefore, EUPS becomes aware of the new product as soon as it's installed.

For details, see the section on the build system and the files in the etc/templates subdirectory.

EUPS tags

All packages come tagged with two EUPS tags: current and conda. As Conda doesn't support having more than one version of a package installed in the same environment, having everything tagged as current is the right thing to do.

It should be easy to extend 'conda-lsst' to take arbitrary additional tags -- all they do is generate extra .chain files. The only complication is that all tags EUPS knows about must be declared in $ROOT/var/opt/eups/ups_db/global.tags file; the code already automatically handles that using a pre-link.sh script (see etc/templates/pre-link.sh.template).

Note that once the package is installed, you can use EUPS to declare additional tags, as you wish.

How the generated recipes build the binaries

conda lsst make-recipes generates the build recipes by filling out the missing information in .template files found in the etc/templates directory. The generation is completely automatic.

The build maximally reuses the eupspkg.sh build system that all LSST EUPS packages use; in essence, the generated build.sh script does the following:

source eups-setups.sh

eupspkg prep
eupspkg config
eupspkg build
eupspkg install

python -m compileall ...

eupspkg decl
eups declare -t <tags> <product> <version>

This is essentially the same sequence performed by EUPS when building packages with eups distrib install.

All the added complexity here (compared to what you'd find in eupspkg.py) comes from the need to handle various corner cases, relocateability, and to inject correct build flags so as to make the binaries redistributable across multiple versions of the operating system (e.g. MACOSX_DEPLOYMENT_TARGET). Note: build.sh.template script also needs some more work and cleaning up -- it's likely possible to substantially simplify it!

This build script is executed by conda build to build and tarball the binary package (with the metadata about the package such as the name, version, and dependencies coming from meta.yaml, which is also generated by filling out a template).

Overrides for packages supplied by Anaconda

Some products that are distributed with EUPS (either as full packages or stubs) already exist in default Conda repositories. Examples include numpy, swig, scons, twisted, etc. We don't want to unnecessarily duplicate functionality by building our own versions.

However, we can't just skip these. Because of the way the current sconsUtils build system works, those packages still need to be declared to EUPS and their .cfg files need to be present. Otherwise their dependents won't know how to build themselves.

The solution to this problem is not to perform the full build of packages that Conda can supply to us, but to only copy the contents of their ups/ directories and declare them to EUPS. To make it clear these are packages that only carry the EUPS config files, we name them lsst-PRODUCTNAME-eups-configs. Secondly, whenever a product depends on one of these packages, we inject the dependency on both the conda package, as well as the relevant -eups-configs package. For example, the afw EUPS product depends on numpy and therefore the conda package lsst-afw will depend on lsst-numpy-eups-configs and numpy.

The products to be considered internal (provided by conda) should be listed by hand in the internal_products variable in config.yaml.

Note that this is really a workaround; the long-term solution is not to depend on .cfg files for builds and instead use something more standard, like pkg-config, as well as make it possible to run conda binaries w/o EUPS.

Skipped products

The code currently skips over a few (optional) products, most notably afw-data (that is very large). This is defined in the skip_products variable in config.yaml

Patching

Any conda-specific patches needed to build the products should be placed in etc/patches/<product>/ directory (the location can be changed by setting patchdir in config.yaml), with a .patch extension. They should apply with patch -p0. See the patches currently there for examples.

Hint: if you're generating the patches with git diff (as you probably should), use something like:

git diff --no-prefix master > mypatch.patch

to have the output at the -p0 level.

We recommend to maintain conda-lsst patches on branches in the package's repository (e.g. a conda-patches branch). To make it easy to create a patch from a brancg in a git repo, use the make-patch utility as:

make-patch patch-name.patch master conda-patches

This creates a file patch-name.patch with a diff between master..conda-patches in the etc/patches/<product>/ directory, where <product> is automatically inferred from the name of the .table file in the git repo's ups/ directory. If you omit the third argument to make-patch, HEAD is assumed. If you omit the second argument, master is assumed. Therefore, assuming you're on conda-patches branch, running:

make-patch patch-name.patch

is equivalent to the invocation above.

Note: there is currently no way to declare a patch should only be applied for certain commits (or commits coming before a certain commit).

PyPI dependencies (and missing/undeclared dependencies)

Some (external, wrapped) EUPS products, most notably sncosmo and pymssql are distutils packaged Python products that transparently use easy_install to install additional dependencies. Conda does not allow this (and rightly so, as it makes it impossible to guarantee offline installs).

For these packages to build, we need to:

• manually create recipes for all of their dependencies, and place them in etc/recipes. The easiest way to do this is by using conda skeleton.
• Declare their depenencies in config.yaml by adding them to the dependencies list, with their name prefixes by recipe/.

Here is an example of the entry for pymssql:

dependencies:
  pymssql:
    run:   [ cython, recipe/setuptools-git ]
    build: [ cython, recipe/setuptools-git ]

Note that some EUPS packages have undeclared dependencies on conda packages as well (e.g., pymssql above depends on cython).

Making packages relocatable

A conda package can be installed into any directory on the end-user's system. It therefore needs to be relocatable.

Conda already has the mechanisms that greatly (and largely transparently) help make this happen (see the entry about relocatable packages in conda documentation).

This mechanism (among other things) ensures that our codes built against libraries suppled by conda (those in $ROOT/lib) will be dynamically linked against them at the end-user's system (this is typically acute for libssl.so, where the system versions vary wildly compared to the Conda ones).

That said, we did have to undertake one additional step. On OS X, we needed to inject the -headerpad_max_install_names option (e.g., see here) to the linker command line for install_name_tool to work reliably.

Note that we don't need (or want) the paths to our libraries to be hardcoded into the libraries they depend on, as EUPS will handle this through LD_LIBRARY_PATH. In fact, hardcoding it (e.g., in a RPATH entry) would make it impossible to mix-and-match EUPS versions of different packages (for those inclined to do so) as the RPATH entry takes precedence over LD_LIBRARY_PATH.

That said, it may be nice to encode the path to other libraries in RUNPATH, to have a default fallback when LD_LIBRARY_PATH is not set.

Binary compatibility

Binary compatibility is largely determined by the presence (or absence) on the end-user's system of system libraries and frameworks that the code has been built against.

On OS X, we build with MACOSX_DEPLOYMENT_TARGET=10.9 set, which should ensure that the built binaries work on OS X 10.9 (Mavericks) and later. Older systems are unsupported because they utilise a different implementation of the C++ standard library (libstdc++ vs libc++).

On Linux, we build on a RHEL5-compatible system. Running on any newer distribution is expected to work.

Naming and Versioning

Conda follows different conventions and imposes additional restrictions on package naming and version format:

• Conda package names must be all lower case. They are allowed to contain the '-' sign, however.

• Conda versions consist of three parts:

  • The version, preferably in PEP-386 format. This is the "real" version of the package. '-' signs are not allowed in version strings. Letters are also undesirable (as they're interpreted -- see the PEP above).

  • The build number. This number should be incremented every time the conda recipe changes and a new binary is rebuilt (while the actual upstream source has not changed).

  • The build string. This is an arbitrary string that isn't used anywhere when comparing versions. It can be used to record some meaningful information about the build itself (e.g., the SHA1 of the source). By convention, the build string is usually of the form <something>_<buildnumber> or (in case there is no prefix), just <buildnumber>

For more details, see here.

By convention, canonical Conda package names are written out as <package_name>-<version>-<buildstring>.

Given those constraints, converting EUPS names+versions to Conda names+versions is done as follows:

• The EUPS product name is transformed to conda package name by replacing all the underscores '_' by dashes, '-'. The dashes as word separators seem to be a generally accepted convention in Conda world.
• We also prepend an lsst- to it, except in cases where it would be silly (e.g., lsst-lsst-distrib).
• Some products are given different names by fiat (see the eups_to_conda_map variable in config.yaml).

Converting versions is tough -- for the exact heuristics see the code in eups_to_conda_version() function in the code. That said, here's roughly what happens:

• Any versions of the form X.Y.Z.W.... are left as is.
• Any version that end in xxx.lsstN are converted to xxx.N
• Any versions of the form of xxx-N are converted to xxx.N
• If a version has a SHA1 embedded, it's moved or copied to the build string portion of the Conda version.
• Any version of the form X.Y.Z... where X is between 10 and 20 is guessed to be an LSST package (as opposed to some external code that we distribute, for example gsl), and a 0 is prepended to it. It is highly unusual in the Conda world to have version 10.x of something that's really alpha-quality code; this brings the version number to sometning more consistent with the state of the codebase.
• Finally, the +N suffixes are converted to .000N suffixes (i.e., formatted as %04d).
• The conda build number always starts at zero, and is incremented every time the conda recipe used to build the source changes (see below).

Some examples:

skypix-10.0+235             -->  skypix-0.10.0.0235_1
obs_test-10.1-4-g461b62d+49 -->  obs_test-0.10.1.4.0049-461b62d_1
boost-1.55.0.lsst1-2+3      -->  lsst-boost-1.55.0.1.2.0003-1

Tracking built recipes

conda lsst does its best to tell you which recipes have already been built, so that you don't have to rebuild them (such recipes have a .done file added to their directory, which the generated rebuild.sh script reads and honors).

It does this by comparing the generated recipe to the recipes of already built packages (on channels that match the our_channel_regex pattern from config.yaml), that have the same name and version (but not the build number or build string). If the recipes are the same (modulo build number/string; see below), the builds would result in identical results and therefore no new build is necessary.

A rebuild is when the same source code (i.e., having the same git SHA), including the dependencies and EUPS versions, is rebuilt using a different recipe (e.g., the recipe may have been modified to change a compiler flag, or add a new a conda-specific patch, etc.). This may happen when the recipe templates in etc/templates are changed. A rebuild will keep the same version, but the build number (and therefore the build string -- by convention, build strings are some <prefix>_<buildnum> or just <buildnum>) will increment to reflect this is a rebuild (an example may be lsst-boost-1.55.0.1.2.0003-0 and lsst-boost-1.55.0.1.2.0003-1).

While conceptually simple, this comparison of recipes would be extremely inefficient if implemented naively: conda lsst would need to download every built package, from every channel, extract the recipes, and compare them to the recipe(s) of interest (modulo build number/string) until a match is found. Since built packages are expected to grow to hundreds of GB, the naive implementation is infeasible.

Instead, we cache the hashes of recipes (minus the lines in meta.yaml that define the build number/string) in a local sqlite database (in pkginfo-cache/<platform>/cache-db.sqlite). When a new recipe is generated, it is hashed and compared to the hashes in the database.

conda lsst refreshes this cache every time it is run, unless --no-cache-refresh option is given; if a new package is detected in any of the channels, it's downloaded, the recipe hashed and cached. Similarly, any packages that are removed are purged from the cache.

This is truly a cache -- it is safe to delete; conda lsst will transparently recover if it's not present.

Package repositories

To allow the user to use the binaries, they need to be uploaded to a "channel" of a conda repository. This repository can either be on the anaconda.org hosted service, or a HTTP-accessible directory on a remote server to which you can SCP the files.

conda lsst upload makes it easy to upload to the latter of the two. The defaults in config.yaml are set up so that just running conda lsst upload will upload to a subdirectory of ~mjuric/public_html/conda at lsst-dev.ncsa.illinois.edu.

For example, assuming I have http://eupsforge.net/conda/dev in my ~/.condarc, running:

conda lsst upload

will upload the built packages to lsst-dev.ncsa.illinois.edu:~mjuric/public_html/conda/dev. Note that to do this, you need to have permissions to write to this directory.

This directory is exposed to the web as http://eupsforge.net/conda/dev; for a user to install from this channel, they'd run:

conda config --add channels http://eupsforge.net/conda/dev

after which the usual conda install command will find the packages available there.

More options are available; see conda lsst upload -h for a more complete summary.

Conda repositories follow a simple package repository format. That they have to be initialized before being used; for example:

cd path/to/my/channel
mkdir osx-64 linux-64
conda index osx-64
conda index linux-64

conda index will create the repodata.json (and repodata.json.bz2) files that conda client uses to search for packages in the channel. conda lsst upload automatically runs conda index after every upload.