Filesystem formatting fails with empty filesystem format arguments

[vroad]

If fileSystemFormatArguments is empty, formating always fails.

etcd3-bootstrap/ebs.go

Line 122 in 80311f3

cmd := exec.Command("sudo", "/usr/sbin/mkfs."+fileSystemFormatType, blockDevice, fileSystemFormatArguments)

However, if I change this line to

// omit fileSystemFormatArguments
cmd := exec.Command("sudo", "/usr/sbin/mkfs."+fileSystemFormatType, blockDevice)

then formatting works. So, passing empty arguments to exec.Command is causing the issue in some way.

A better solution is building args dynamically with arrays?
https://stackoverflow.com/questions/22781788/how-could-i-pass-a-dynamic-set-of-arguments-to-gos-command-exec-command/22781927#22781927

Full log from journald:

-- Logs begin at Sun 2019-08-18 15:40:54 UTC, end at Sun 2019-08-18 15:55:32 UTC. --
Aug 18 15:41:16 ip-10-200-94-194 systemd[1]: Starting etcd-bootstrap.service...
Aug 18 15:41:16 ip-10-200-94-194 curl[1414]:   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
Aug 18 15:41:16 ip-10-200-94-194 curl[1414]:                                  Dload  Upload   Total   Spent    Left  Speed
Aug 18 15:41:17 ip-10-200-94-194 curl[1414]: [237B blob data]
Aug 18 15:41:17 ip-10-200-94-194 curl[1414]: [79B blob data]
Aug 18 15:41:17 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:17 Resolved volume peer-1-ssd.etcd3-test.ap-northeast-1.i.staging.example.com to vol-05d9bb859e4814f4f
Aug 18 15:41:17 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:17 Will attach volume vol-05d9bb859e4814f4f to instance id i-03d54bd5d297ab722
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:18 Waiting for attachment to complete. Current state: attaching
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:18 Waiting for attachment to complete. Current state: attaching
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:18 Waiting for attachment to complete. Current state: attaching
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:18 Attached volume vol-05d9bb859e4814f4f to instance i-03d54bd5d297ab722 as device /dev/xvdf
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:18 Checking for existing filesystem on device: /dev/xvdf
Aug 18 15:41:18 ip-10-200-94-194 sudo[1429]:     root : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/usr/sbin/blkid /dev/xvdf
Aug 18 15:41:18 ip-10-200-94-194 sudo[1429]: pam_unix(sudo:session): session opened for user root by (uid=0)
Aug 18 15:41:18 ip-10-200-94-194 sudo[1429]: pam_unix(sudo:session): session closed for user root
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: 2019/08/18 15:41:18 Filesystem not present
Aug 18 15:41:18 ip-10-200-94-194 sudo[1440]:     root : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/usr/sbin/mkfs.ext4 /dev/xvdf
Aug 18 15:41:18 ip-10-200-94-194 sudo[1440]: pam_unix(sudo:session): session opened for user root by (uid=0)
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: mke2fs 1.44.5 (15-Dec-2018)
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: mkfs.ext4: invalid blocks '' on device '/dev/xvdf'
Aug 18 15:41:18 ip-10-200-94-194 sudo[1440]: pam_unix(sudo:session): session closed for user root
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: panic: mkfs.ext4 failed: exit status 1
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: goroutine 1 [running]:
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]: main.main()
Aug 18 15:41:18 ip-10-200-94-194 etcd3-bootstrap[1420]:         /home/ubuntu/go/src/github.com/monzo/etcd3-bootstrap/main.go:65 +0x4d0
Aug 18 15:41:18 ip-10-200-94-194 systemd[1]: etcd-bootstrap.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
Aug 18 15:41:18 ip-10-200-94-194 systemd[1]: etcd-bootstrap.service: Failed with result 'exit-code'.
Aug 18 15:41:18 ip-10-200-94-194 systemd[1]: Failed to start etcd-bootstrap.service.

mkfs.ext4: invalid blocks '' on device '/dev/xvdf'

It looks like mkfs command tried to parse empty argument and failed.