Detailed comparison between EJPM and Spack¶
What packet manager to use? The recommendation is: to use EJPM for personal laptops with Linux OS for personal use and development. Use Spack on farms or if you are familiar with Spack or use Spack for other projects.
Precise comparison table:
| EJPM | Spack | |
|---|---|---|
| Design | User friendly CLI build scritps replacement. Laptops and workstations in mind. | Full featured package manager capable to build and install multiple software versions and configurations. Supercomputers and farms in mind but laptops possible. |
| Dependencies | Use system packages (yum, apt) as much as possible | Use few system packages and build ALL dependencies |
| Utilize user packages (ROOT, Geant4) |
Easy to add | Possible via editing configs but cumbersom |
| Packages variety | Only ESCalate and EIC related | All kinds of packages |
| Versions | Limited support of package versions | Spack shines here |
| Updates | No automatic package updates | |
| Development | Very easy to modify/develop code | Possible with develop environments. Cumbersom compared to EJPM |
| Support | EIC community | EIC community for EIC packages. Large science (HEP, Astrophysics, etc.) community for the rest of the packages and Spack itself |
EJPM was designed with user laptops and work stations in mind to be a user friendly CLI alternative to “build scritps” that compiles compiling chains of packages with right flags. Something that users can simply do pip install ejpm; ejpm install package EJPM was made.
Spack is a full featured multi-platform package manager designed for clusters and super computers. Spack is capable to build and install multiple versions and configurations of software and shines here. It is possible to use spack on a laptop or a personal workstation also, but learning curve is steeper than with EJPM.
EJPM uses as much system packages as possible. E.g. EJPM have special command like ejpm dep ubuntu which lists all packages to be installed by your system package manager (yum, apt).
Contrary to this Spack tries to build as much dependent packages as possible. When building something like ROOT, Spack goes as deep as building its own Python, Perl, Mesa and even zip libraries. That is the first major difference between EJPM and Spack. As the result EJPM uses less compilation time and dependencies are much less complicated but is much more dependent on what is installed and configured in the system. On the other hand Spack is much more system independent, but building a lot of libraries takes much more time and more compilation error prone.
To use packages ejpm users have to source an environment file which is re/generated every time EJPM configuration is updated. It is possible to have different versions of packages but users have to control it manually.
Spack utilizes modules which is certainly more versatile and sutable for large distributed systems (while works very well on workstations also). Spack uses rpath to link depencies between each other
Spack has large dependencies trees. Even if one flag is different between some packages it might try to build an alternative tree. Simply saying Spack tends to install many versions of ROOT or Geant4 packages and which takes large disk space and time. It is avoidable but requires additional care and supervision from user.
EJPM also allows to install new versions of a package but it doesn’t check if it might affect downstream dependencies. That is kind of great disadvantage of EJPM compared to Spack.
There is no automatic updates both in Spack and EJPM. Idea of Spack is that you just install a new version (and it installs all needed/updated dependencies).