Properly Loading Packages

[timchisamore]

Hello,

I am a drake user coming over to targets now that it is on CRAN and am loving it!

One question I had is regarding properly loading packages into the workflow. I know in the documentation you had mentioned using the packages argument in the tar_option_set function in the _targets.R file. However, with drake I use a requirements.R script to load packages, resolve package conflicts, set environment variables, and set the project path using the i_am function from the here package. I then would source this file in the _drake.R file before using walk from purrr to source all functions in my R directory, and finally define the drake plan. I learned this approach from @MilesMcBain here and I believe you featured it in the drake documentation as well. I can provide further details regarding what these files look like, should that be required.

Is there a better way to do this in targets using some of the arguments to the tar_option_set function (since I'm including more than just packages)?

All the best,

TC

[wlandau]

If you do not set the packages option in tar_option_set(), then the packages will default to whatever you load in _targets.R, which is equivalent to how you were using drake. However, if you have a lot of packages, then utilities like tar_outdated() and tar_visnetwork() will spend time loading packages they do not use. So I usually recommend tar_option_set(packages = ...) for whatever packages the targets need when they run.

Environment variables, packages with conflicts to manage, and here settings do not carry over to parallel workers created by tar_make_clustermq() and tar_make_future(). So rather than using _targets.R to configure all that, I recommend using .Renviron and .Rprofile files local to the project. (.Renviron and .Rprofile outside the project are ignored by callr and thus the tar_make*() functions.)

[timchisamore]

Thanks for taking the time to respond, I am going to explore this further tonight and over the next few days. I am very excited to adopt them within my workflow!