====== Packages ======
{{:software:valet:valet-icon.png?128 |}}In VALET, a //package// is a software component, where "component" can mean an application, a code library, a set of man pages, or a combination of all these pieces. For example, Mathematica would be an application: all the end user needs is for the appropriate directory to be on his/her ''PATH'' so that typing ''mathematica'' starts the program((The ''mathematica'' startup script itself alters the environment further so that its own shared libraries are found properly, etc.)). On the other hand, a program using OpenMPI for parallelism might need both the ''PATH'' and ''LD_LIBRARY_PATH'' configured in order to function.
As newer versions of software are released, the older versions are usually not removed immediately when the new are installed on a system. Users need time to adapt their workflow to changes in the software; occasionally the changes may be radical enough (e.g. Python 2 versus 3) that the workflow simply cannot be adapted to the new version. A VALET //package// can have multiple //versions// associated with it. Using the same examples as above, the system may have Mathematica 6, 7 and 8 available to users. Likewise, OpenMPI 1.3.3 and 1.4.2 may be available, in each case in standard TCP and Myricom-enabled flavors.
VALET uses a //versioned package id// similar to those used in "modules". The //versioned package id// is a string containing two pieces, the package and the version, separated by a "/" character:
mathematica/6
mathematica/7
mathematica/8
openmpi/1.3.3
openmpi/1.3.3-mx
openmpi/1.4.2
openmpi/1.4.2-mx
A special form of //versioned package id// references whatever version of a package is indicated to be the default version:
mathematica/default
openmpi/default
The "/" and version information can also be omitted to indicate the default version of a package:
mathematica
openmpi
The default version is specified in each package's configuration file -- more on that later.
===== What Packages Are Available? =====
A list of available packages is displayed using the ''vpkg_list'' command:
[user@host ~]$ vpkg_list
Available packages:
openmpi
pgi
matlab
For individual packages, a list of versions is displayed using ''vpkg_versions'':
[user@host ~]$ vpkg_versions openmpi
Available versions in package (* = default version):
[/opt/shared/valet/2.0/etc/openmpi.vpkg_json]
openmpi Open MPI: Message-Passing Interface
gcc alias to openmpi/1.8.2
intel64 alias to openmpi/1.8.2-intel64
1.8.2-intel64 Version 1.8.2, with Intel64(2015) compilers
1.8.2-gcc-4.8.3 Version 1.8.2, with GCC(4.8.3) compilers
1.8 alias to openmpi/1.8.2
* 1.8.2 Version 1.8.2, with GCC(system) compilers
The "*" indicates which version is currently the default.
A verbose description of a package or package version can be displayed using the ''vpkg_info'' command with a non-versioned package id (e.g. ''mathematica'') or a versioned package id (e.g. ''mathematica/6''):
[user@host ~]$ vpkg_info openmpi/default
[openmpi/1.8.2] {
Version 1.8.2, with GCC(system) compilers
prefix: /opt/shared/openmpi/1.8.2
affect dev env:
add std paths:
}
===== Applying Environment Changes from Package(s) =====
One or more packages are setup in the environment using the ''vpkg_require'' command:
[user@host ~]$ vpkg_require openmpi/default
Any problems encountered will result in no changes being made to the environment. For example, trying to configure two versions of OpenMPI simultaneously yields:
[user@host ~]$ vpkg_require openmpi/default openmpi/pgi-1.3.3
ERROR: unable to add versioned package: openmpi/pgi-1.3.3 conflicts with version: openmpi/pgi10-1.4.2-mx
Problems may occur due to dependencies or incompatibilities that a version of a package has w.r.t. another package:
[user@host ~]$ vpkg_require openmpi/pgi10-1.4.2 pgi/8
ERROR: unable to add versioned package: pgi/8 conflicts with version: pgi/10
[user@host ~]$ vpkg_require dummy gaussian
ERROR: incompatibility detected between a previously added package and gaussian/g03.c02
[user@host ~]$ vpkg_require gaussian dummy
ERROR: incompatibility detected between dummy/standard and gaussian/g03.c02
===== Undoing Environment Changes =====
VALET attempts to make a snapshot of your environment prior to each invocation of ''vpkg_require''. To remove the changes made by your last use of ''vpkg_require'', use the ''vpkg_rollback'' command:
[user@host ~]$ vpkg_rollback
WARNING: no snapshots defined
The above message is displayed because ''vpkg_require'' has not yet been called! If you have called ''vpkg_require'' more than once, you can also rollback through more than just the last call to ''vpkg_require'' by supplying the number of rollbacks to attempt. For example,
[user@host ~]$ vpkg_rollback 2
would perform two rollbacks. To remove all changes made to your environment since the first use of ''vpkg_require'', use the ''all'' argument:
[user@host ~]$ vpkg_rollback all
===== What If I Forget These Commands? =====
No problem! Just type ''vpkg_help'' on the cluster for a summary of the commands.
[user@host ~]$ vpkg_help
Package ids:
A package is identified by an identifier and an optional version identifer separated
by a forward slash:
matlab Default version of matlab
matlab/default Default version of matlab
matlab/R2007a R2007a version of matlab
Commands are:
vpkg_cli Invoke the UDSEC command-line utility
vpkg_list List the packages defined for UDSEC management
vpkg_versions List the versions available for a given package
vpkg_info Show information for a package (or a specific
version of a package)
vpkg_require {} Add configuration for the given packages
to the environment
vpkg_devrequire {} Add configuration for the given packages
to the environment; includes setup of the LDFLAGS
and CPPFLAGS variables with library/header paths
for the packages
vpkg_rollback {#|all} Attempt to restore the environment state that
existed before the last vpkg_require. A numerical
argument does multiple rollback operations, e.g.
"vpkg_rollback 2" will revert the last two calls
of "vpkg_require". The argument "all" reverts
every call to "vpkg_require" made in the shell.
vpkg_history Display a list of all versioned packages that
have been added to the environment.
===== Can I Add My Own Packages? =====
Sure! Version 1 of VALET exclusively used XML for specification of package files, and is documented in the next section. For VALET 2, both XML and JSON formats are available.
To augment the system-wide package files, create a ''.valet'' directory in your home directory and add your own package definition files inside it. VALET automatically looks in ''~/.valet'' for package files. VALET will also check any directories present in the ''VALET_PATH'' environment variable((In VALET 1 the ''VALET_SYSCONFDIR'' variable must be used, not ''VALET_PATH'')). The ''VALET_PATH'' behaves like the ''PATH'' envrionment variable:
export VALET_PATH="${HOME}/valet/etc:${WORKDIR}/sw/valet"
The paths in ''VALET_PATH'' will be consulted in the order they are specified, and VALET's default configuration directory is implicitly added to the end of the list of paths. This means you can "override" packages that are defined elsewhere. For example, if I add ''openmpi.vpkg'' to my ''~/.valet'' directory, then ''vpkg_require openmpi'' will use the definitions in ''~/.valet/openmpi.vpkg'' in preference to the ones defined by the system administrator in VALET's default configuration directory.
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