R Sendmail Tricks
One of the most useful things I’ve found to do with R is to make periodic checks of various things in my data environment. This is particularly useful in places where 2 systems store the same data that in theory should be kept in sync, but in practice exhibit drift for whatever reason. It’s easy to create a script that compares both systems and flags any discrepancies that are found. The trick then is what to do with those results? What I show here is a way to email the results, either as a simple message, or as a message with an attachment, to several users.
Simple Email Example
1 # message text
2 token_status_msg <- sprintf("WARNING! - API token expires in %s days",
3 days_to_expire)
4
5 # mail info
6 from <- "<REPORT_TOOL@fubar.com>" # optional value
7 to <- "<Royer@domain.com>"
8 subject <- "API token about to expire!"
9 body <- token_status_msg
10 cc <- "<SpecialCC@domain.com>"
11
12 # mail command
13 sendmail(from,
14 to,
15 subject,
16 body,
17 cc,
18 control=list(smtpServer= "mail.domain.com")
19 )
Email with Attachment
1 # attachment
2 write.xlsx(bad_data, "bad_data.xlsx", overwrite = TRUE)
3
4 # message text
5 mail_message <- paste("The attached records are bad.",
6 "This is an automated check, do not reply.",
7 sep="\n\n")
8
9 # mail info
10 from <- sprintf("<REPORT_TOOL@fubar.com>")
11 to <- sprintf("<Royer@domain.com>")
12 cc <- sprintf("<SpecialCC@domain.com>")
13 subject <- "Bad Data Found"
14 attachment <- sendmailR::mime_part(x = "bad_data.xlsx")
16 body <- list(mail_message, attachment)
17
18 # mail command
19 sendmail(from,
20 to,
21 subject,
22 body,
23 cc,
24 control=list(smtpServer="mail.domain.com")
25 )
Final Thoughts
While extremely useful, there are some limitations to this approach. The main one being that you need a sendmail server available that can actually send the message. An additional one is that you can only specify one recipient for each of the to: or cc: types.
UPDATE: The preceeding comment regarding the limit of a sigle email recipient per to: and cc: is incorrect. To specify more than one user, simply place their email addresses in a list.
to <- list("<email1@domain.com>", "<email2@domain.com>")
```
R_Hacks