map has no entry for key

[hmoffatt]

No matter what I use for a template I always get an error saying that the template variables are undefined;

Example template

ID {{ .ID }}

Test invocation:

env ID=blah go/cmd/bin/docker_entrypoint -template foo.template /bin/true
foo.template
error rendering template foo.template: template: foo.template:2:6: executing "foo.template" at <.ID>: map has no entry for key "ID"

[bejelith]

The environment variable needs to reflect the template name, this is to support multiple templates in a run.

So in your specific case the correct way is
env foo_template_ID=blah go/cmd/bin/docker_entrypoint -template foo.template /bin/true

[hmoffatt]

This didn't work;

$ env foo_template_ID=blah go/cmd/bin/docker_entrypoint -template foo.template /bin/true
foo.template
error rendering template foo.template: template: foo.template:2:6: executing "foo.template" at <.ID>: map has no entry for key "ID"

but this did, with foo_ID instead of foo_template_ID:

$ env foo_ID=blah go/cmd/bin/docker_entrypoint -template foo.template /bin/true
foo.template
Template foo.template rendered

Is that correct?

[hmoffatt]

I think there is some sort of case sensitivity issue too - if the template is server.properties.template, the environment variables also have to have lowercase prefixes. The example in the README doesn't work because of this.

$ env SERVER_PROPERTIES_LISTEN_ADDRESS="localhost" SERVER_PROPERTIES_LISTEN_PORT=8080 SERVER_PROPERTIES_ID=1 go/cmd/bin/docker_entrypoint -template server.properties.template /bin/true
server.properties.template
error rendering template server.properties.template: template: server.properties.template:1:18: executing "server.properties.template" at <.LISTEN_ADDRESS>: map has no entry for key "LISTEN_ADDRESS"

[bejelith]

yes, it is case sensitive and the .template is ignored, i added some more documentation in the readme

[hmoffatt]

Ok thanks it looks better now with the lowercase environment variables.