pkgcache and Posit Package Manager on Linux
Gábor Csárdi
2024-11-07
Source:vignettes/ppm.Rmd
ppm.Rmd
PPM and P3M
Posit Package Manager (PPM) is a Posit product to help organizations organize R and Python packages.
Posit Public Package Manager (P3M) is a free instance of PPM.
pkgcache deals with all PPM instances the same way currently, including the P3M instance.
In the following, by PPM we mean any PPM instance.
Why PPM?
- Fast installation. PPM has binary packages on Linux, for many distributions, for the last 5 R releases.
- New packages on older R versions. On Windows, new package versions are available as binary packages, on older R versions as well.
- Time traveling. Use an older state of the repository, as it was on a specific date.
pkgcache and PPM on Linux
For a better user experience pkgcache handles PPM repositories specially on Linux.
Call pkgcache::ppm_has_binaries()
to decide if PPM
builds binaries for your platform:
pkgcache::ppm_has_binaries()
## [1] TRUE
You can use pkgcache::current_r_platform()
to see if
pkgcache detects your platform correctly:
pkgcache::current_r_platform()
## [1] "x86_64-pc-linux-gnu-ubuntu-22.04"
Setting up PPM
Set the repos
option to a PPM URL, as suggested by the
PPM setup web page. E.g. see https://packagemanager.posit.co/client/#/repos/2/overview
for P3M.
You can also set the PKGCACHE_PPM_URL
environment
variable to the base URL of a PPM instance (e.g. https://packagemanager.posit.co for P3M), and the
PKGCACHE_PPM_REPO
environment variable to the default PPM
repository. The pkgcache::repo_resolve()
and
pkgcache::repo_add()
functions use these environment
variables (if they are set) to construct PPM URLs. See
?ppm_repo_url
for details.
PPM repository URLs
A PPM repository URL for Linux binary packages has the following form:
{base}/{repo}/__linux__/{binary_url}/{id}
where {base}
is the base URL of the PPM instance,
{repo}
is a PPM repository, {binary_url}
is
the code name of a release of a Linux distribution
(e.g. rhel9
), and {id}
is the identifier (or
date) of a PPM snapshot or latest
for the latest
snapshot.
ppm_platforms()
lists platforms supported by a PPM
instance:
pkgcache::ppm_platforms()
## # A data frame: 30 × 6
## name os binary_url distribution release binaries
## <chr> <chr> <chr> <chr> <chr> <lgl>
## 1 centos7 linux centos7 centos 7 TRUE
## 2 centos8 linux centos8 centos 8 TRUE
## 3 rhel9 linux rhel9 rockylinux 9 TRUE
## 4 opensuse15 linux opensuse15 opensuse 15 TRUE
## 5 opensuse152 linux opensuse152 opensuse 15.2 TRUE
## 6 opensuse153 linux opensuse153 opensuse 15.3 TRUE
## 7 opensuse154 linux opensuse154 opensuse 15.4 TRUE
## 8 opensuse155 linux opensuse155 opensuse 15.5 TRUE
## 9 opensuse156 linux opensuse156 opensuse 15.6 TRUE
## 10 opensuse42 linux opensuse42 opensuse 42.3 TRUE
## # ℹ 20 more rows
The binary_url
column contains the code name that you
need to use in the repository URL.
ppm_snapshots()
lists all PPM snapshot dates and
ids:
pkgcache::ppm_snapshots()
## # A data frame: 2,585 × 2
## date id
## <date> <chr>
## 1 2017-10-10 2017-10-10
## 2 2017-10-11 2017-10-11
## 3 2017-10-12 2017-10-12
## 4 2017-10-13 2017-10-13
## 5 2017-10-14 2017-10-14
## 6 2017-10-15 2017-10-15
## 7 2017-10-16 2017-10-16
## 8 2017-10-17 2017-10-17
## 9 2017-10-18 2017-10-18
## 10 2017-10-19 2017-10-19
## # ℹ 2,575 more rows
You can use the snapshot ids or dates in the PPM repository URL to select a particular snapshot. E.g. these two repository URLs are equivalent:
https://packagemanager.posit.co/cran/__linux__/centos7/5
https://packagemanager.posit.co/cran/__linux__/centos7/2017-10-10
Linux platforms
pkgcache generalizes R’s “machine-vendor-OS” platform triplet on Linux to include the distribution and release as well. E.g. the platform of the machine building this document is:
pkgcache::current_r_platform()
## [1] "x86_64-pc-linux-gnu-ubuntu-22.04"
PPM Linux binary packages
R does not have built-in support for binary Linux repositories, so PPM offers binary Linux packages as source packages. This is possible because R recognizes binary packages at installation time, and handles them appropriately.
pkgcache detects binary PPM repositories, and constructs their platform string:
print(
pkgcache::meta_cache_list(package = c("ggplot2", "pkgcache"))[, c("package", "mirror", "platform")],
width = Inf
)
## # A data frame: 4 × 3
## package mirror
## * <chr> <chr>
## 1 ggplot2 https://packagemanager.posit.co/cran/__linux__/jammy/latest
## 2 pkgcache https://packagemanager.posit.co/cran/__linux__/jammy/latest
## 3 ggplot2 https://cran.rstudio.com
## 4 pkgcache https://cran.rstudio.com
## platform
## * <chr>
## 1 x86_64-pc-linux-gnu-ubuntu-22.04
## 2 x86_64-pc-linux-gnu-ubuntu-22.04
## 3 source
## 4 source
Metadata discrepancies
Occasionally, the PPM metadata can be outdated, and pkgcache will wrongly think that PPM has a binary for a package, whereas it does not, or the opposite might also be true.
When pkgcache downloads a package as an update to the package cache, it detects from the PPM response headers whether the downloaded package is indeed of the expected type. If not, then pkgcache updates its knowledge about the package.
Supported R versions
Different PPM instances may support different R versions. The public
P3M instance supports the last five R releases. pkgcache will
automatically check if your configured PPM instance supports your R
version, and ppm_has_binaries()
, repo_set()
will act accordingly. You can use the
pkgcache::ppm_r_versions()
function to list the R versions
supported by your instance:
pkgcache::ppm_r_versions()
## # A data frame: 6 × 1
## r_version
## <chr>
## 1 4.4
## 2 4.3
## 3 4.2
## 4 4.1
## 5 4.0
## 6 3.6
Note that these version numbers do not include the patch version.
E.g. 4.2
means that all 4.2.x
R versions are
supported.
pkgcache and PPM on Windows
A PPM instance can have support for Windows binaries, the public P3M instance does support them.
The R package system supports Windows binaries out of the box, so
setting up PPM on Windows simply means setting the repos
option to a PPM repository. E.g. for the public P3M this would be
something like:
options(repos = c(
RSPM = "https://packagemanager.posit.co/cran/latest",
CRAN = getOption("repos")[["CRAN"]]
))
Instead of latest
you can use a different snapshot, of
course, and you can also use repo_resolve()
to construct
the URL for your preferred snapshot.