Lubridate error: ‘/etc/localtime’ is not a symlink

Question

When I run now() in lubridate I get this error.

Warning: Your system is mis-configured: ‘/etc/localtime’ is not a symlink Warning: It is strongly recommended to set environment variable TZ (time zone) to ‘Etc/Universal’ (or equivalent)

Then I get the current time tuned to UTC.

[1] "2019-04-14 15:50:18 UTC"

I've looked around for this on SO and github and I'm not finding much content. I'm running RStudio Server on a Linux box on EC2.

Here is the top of the output from sessionInfo()

R version 3.5.3 (2019-03-11)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Amazon Linux AMI 2018.03

I looked for the timezone options in /usr/share/zoneinfo/ and saw Pacific which matches up with my timezone. I ran Sys.setenv(TZ='Pacific'), but it still serves the wrong time.

[1] "2019-04-14 16:15:04 Pacific"
Warning message:
In with_tz(Sys.time(), tzone) : Unrecognized time zone ''

Answer 1

We need more information to help you -- "on a Linux box" is not all that specific.

Looking at the function in question we see

 R> lubridate::now
 function (tzone = "")
 with_tz(Sys.time(), tzone)
 <bytecode: 0x55fd86dd68a8>
 <environment: namespace:lubridate>
 R> 

so a base R call of Sys.time() coupled with some package-specific code to get to the timezone.

Now, how timezone information, something somewhat specific to the local installation, is provided to R is not standardized. Hence the error message.

I needed it once for another package (of mine) and R (at the time) was not doing enough -- so see

 R> gettz::gettz()
 [1] "America/Chicago"
 R> 

R has since improved and added a very similar heuristic (of looking in other possible places) so it is more robust. So please test some more and tell if R knows the timezone even if lubridate does not.

In either case, you could (should ?) set it to help the system.

And if R finds it, why not just use base R?

R> format(Sys.time(), "%F %T %Z")  
[1] "2019-04-14 11:06:54 CDT" 
R>