Prevent users from using "{}" in template names

[jonboulle]

I was experimenting with unit file templating and built a small tool to generate templates and then start services using {1,2,3} syntax. But accidentally somehow my shell escaped the {} making fleetctl to submit an actual unit named @{1,2,3}.service.

This made me have to go through all sorts of hidden keys and places to clean it up. In some places it actually fleet took it as 1,2 and 3 but in some places not. Maybe there should be some checks for this?

[bcwaldon]

So I tried to reproduce this using master and saw the following behavior:

$ cat examples/foo\@.service
[Service]
ExecStartPre=/usr/bin/echo "instance=%i"
ExecStart=/usr/bin/sleep 1000
core@core-01 ~/fleet $ fleetctl start "examples/foo@{1,2,3}.service"
$ fleetctl list-unit-files
UNIT                    HASH    DSTATE          STATE           TMACHINE
foo@{1,2,3}.service     5f4c1d1 launched        inactive        9559d65f.../172.17.8.103

On the node to-which the unit was scheduled, I see this:

Sep 04 00:14:05 core-03 fleetd[1066]: ERROR generator.go:40: Failed fetching current unit states: Unit name foo@{1,2,3}.service is not valid.

The behavior that I suspect you're seeing was fixed in #793. I totally agree fleet should not accept fleet units with invalid names in the first place, but this is difficult to enforce until all requests are going through the API. I've filed that bug here: #867.

[jonboulle]

This is intentionally not exhaustive; the correct place for that is the unit tests covering these functions. This is just a simple functional test of the common cases we've seen to ensure that fleetctl does the validation.

[bcwaldon]

@jonboulle LGTM