Create multiple config files from templates

[lorenz]

I want to run tinc with confd, tinc requires you to have a configuration file for every host. These can all be built from the same config. I'd like to have the host list and the host-specific configuration stored in etcd and afterwards turned into files by confd. Any chance that this is getting added?

[kelseyhightower]

@lorenz What would that look like? What data would each template receive?

[lorenz]

@kelseyhightower Basically there would be a go template which is the same for every file. The data would be equal (structure-wise, not data-wise) but grouped up in directories, one for every file. Does that make sense?

[mborho]

+1

The possibility to generate config files programmatically would be very handy.

[kelseyhightower]

@mborho Can you give me an idea of what an example resource template and template file would look like?

[mborho]

@kelseyhightower Good question :)
Let me start with the use case first. Having some keys in the following way:

/auth/foo/user1
/auth/foo/user2
/auth/bla/user1

Which should result in multiple files after processing:

foo.htpasswd
bla.htpasswd

Currently I'm using an intermediate file, which gets cut by some awk magic added to the restart_cmd.

But perhaps a custom tag is possible in the templates, something like this:

{{configfile "filename" "fileprefix" "content"}}

And in the template resource something like:

dest_dir_multiple = /path/for/configfiles/

So the config-files would be saved as /path/for/configfiles/[filename].[fileprefix]

Makes this any sense for you?

[crunchywelch]

FWIW, this maybe addresses this issue: #332

[kelseyhightower]

After thinking about this for a while, I'm going to reject this feature in order to keep confd simple. confd is really designed to map one template resource to a single output file. This keeps confd simple, but as you pointed out it does limit the types of problems confd can solve.

I'm willing to make this trade off though in order to keep confd simple.

[openxxs]

Hi, @bacongobbler I need to confd a nginx.conf file and a ./conf.d/upstream.conf file, which nginx.conf includes ./conf.d/upstream.conf. Because these two files are determined by different etcd clusters, I have to start a confd process for each.
toml file for nginx.conf:

[template]
prefix = "/domeos/loadbalancer/nginx/nginx03"
src = "nginx.conf.tmpl"
dest = "/etc/nginx/nginx.conf"
keys = [
    "/conf",
]
check_cmd = "/usr/sbin/nginx -t -c {{.src}}"
reload_cmd = "/usr/sbin/nginx -s reload"

toml file for ./conf.d/upstream.conf:

[template]
src = "upstream.conf.tmpl"
dest = "/etc/nginx/conf.d/upstream.conf"
keys = [
    "/registry/pods/default",
]
check_cmd = "/usr/sbin/nginx -t -c /etc/nginx/nginx.conf"
reload_cmd = "/usr/sbin/nginx -s reload"

When I change the /registry/pods/default value and generate a fault ./conf.d/upstream.conf, confd tells me:

INFO /etc/nginx/conf.d/servers.conf has md5sum 457c221119f29b5eeaa0a45ddae63d52 should be 46d8305693d13c7fbaf8d509bb284c94
2016-06-28T02:40:19Z 26c17fae16ff ./confd[426]: INFO Target config /etc/nginx/conf.d/upstream.conf out of sync
2016-06-28T02:40:19Z 26c17fae16ff ./confd[426]: ERROR "2016/06/28 02:40:19 [emerg] 436#436: "upstream" directive is not allowed here in /etc/nginx/conf.d/upstream.conf:4\nnginx: [emerg] "upstream" directive is not allowed here in /etc/nginx/conf.d/upstream.conf:4\n"
2016-06-28T02:40:19Z 26c17fae16ff ./confd[426]: ERROR exit status 1

It means check_cmd works. But the ./conf.d/upstream.conf has been updated, which makes nginx product ERROR.
Dose check_cmd have to be /usr/sbin/nginx -t -c {{ .src }}? What if check_cmd = "bash myCmd.sh"?

[bacongobbler]

check_cmd can be whatever you want it to be. It could literally be /bin/true if you don't care about validating your templates.

[waszi]

I am using confd to configure nginx on multiple containeres, domain config/maps etc it is easy to split config without multiple destination but there is small exception. SSL Certificates requires separate files with name based on domain name. Any ideas how to solve this ?

Hi @kelseyhightower , do we support multiple destinations for config files now?