Crontab won't run go / golang program

I have setup crontab to run a compiled golang script. The script is responsable for copying a folder to a ftp. Nothing special in this.

I can run the program in the commandline by just typing "/backup/main" And it all works.

Now I want to run this program every night. I have setup the cronjob to run every 5 minutes to test if it works. And it dont!

If I check the syslog I can see the program is beeing called, but nothing happens.

The file "/backup/main" is chmod a+x
The crontab is set in "sudo" (sudo crontab -e). So alle permissions should be ok.

The line in crontab:

*/5 * * * * /backup/main

Hops someone can help.

Hoping to help others who couldn't find the solution as me:

The issue can be resolved by adding path and gopath variables to the crontab -e file.

you can find them by running echo $PATH echo $GOPATH

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/usr/local/go/bin:/root/bin
GOPATH=/var/projects/src

# +---------------- minute (0 - 59)
# |  +------------- hour (0 - 23)
# |  |  +---------- day of month (1 - 31)
# |  |  |  +------- month (1 - 12)
# |  |  |  |  +---- day of week (0 - 6) (Sunday=0)
# |  |  |  |  |
  */5 * * * * /backup/main

Your code may not be running due error that go was not able to find packages

i.e. the third packages that you installed by running go get example

go get gopkg.in/gomail.v2

The problem is that you may have go get from your working directory!
In my case which is GOPATH=/var/projects/src

you can see the package inside

/your/working_directory/src/pkg/linux_amd64

Maybe something wrong, and the program print some log, but the log will be redirected to the /dev/null, and you can't check the error log.
you can add this to print the log to some log file.

*/5 * * * * /backup/main 1>> /path/to/log/file 2>>/path/to/error_log/file

The conventional wisdom about cron silent failures is that it's probably the environment. By wrapping your golang program in a shell script, you can control the environment (and get your profiles to run). You can also put in useful debug bits like "env".

To simulate cron with it's empty env run:

env -i ./myscript.sh

where myscript.sh is chmod +x and just runs "env". Then put your golang command in there and see if it still works without the environment. Then when you've proved it's the environment (hopefully), use a shell script in cron.

I stumbled onto this post as this was exactly the problem that I encountered.
crontab not running my compiled golang binary.
For me, the problem was the incorrect configuration of the crontab line.
I followed the following format in the configuration and that did the trick for me:

* * * * * cd folder_containing_exe && ./exe_name

note! This runs the binary every minute
source: https://stackoverflow.com/questions/3474280/how-to-set-up-a-cron-job-to-run-an-executable-every-hour
Hope this can perhaps help someone with a similar issue.

Since my code was package based, with a go.mod file, the error I was getting after viewing crontab logs was that the script could not find the imports (since they were local referenced from the location of the script instead of globally referenced in go.mod). To mitigate this and get it working:

1. Create a shell script scriptrunner.sh

#!/bin/bash
cd /full/path/mygocode/ # the place where your go code is
/snap/bin/go run script.go # (for Ubuntu 22+, or /usr/bin/go)

2. chmod +x scriptrunner.sh
3. Update path in crontab to point to new filename like */5 * * * * ./path/scriptrunner.sh

Note this works the same if this has been a compiled binary. It is helpful to wrap the executable as a bash script to ensure you are controlling what you are executing and from where.