fixes #1452 set path separator to slash in interpolation and add a test case

[lifubang]

Signed-off-by: Lifubang lifubang@acmcoder.com

- What I did
Please see issue #1452 , Variable type conversion in Compose file breaks if service name contains dot.

- How I did it
set path separator from dot to slash in interpolation and add a test case

- How to verify it
After this patch:

root@dockerdemo:~/testd# cat file2.yaml 
version: "3.0"
services:
  app.test_1:
    image: redis
    ulimits:
      nofile:
        soft: ${APP_NOFILE}
        hard: ${APP_NOFILE}
root@dockerdemo:~/testd#

root@dockerdemo:~/testd# APP_NOFILE=1 ~/gocode/src/github.com/docker/cli/build/docker stack deploy -c file2.yaml stk2
Creating service stk2_app.test_1

- Description for the changelog
set path separator from dot to slash in interpolation

- Addition info
But, but, the daemon said:
failed to create service stk2_app.test_1: Error response from daemon: rpc error: code = InvalidArgument desc = name must be valid as a DNS name component
The daemon's check regexp is ^[a-zA-Z0-9](?:[-_]*[A-Za-z0-9]+)*$, don't contain dot.
But I think this is another issue( see #1470 ).
At least, by this patch, we can get the right response.

[thaJeztah]

Right, if I understand correctly, this only fixes that when parsing the YAML, so that it doesn't interpret foo.bar.baz: test as

foo
  bar
    baz: test

I don't think we should change this, as it would probably break people using the existing syntax

Servicenames are not allowed to contain a ., as they are also used in DNS, which may result in service-names conflicting.

The correct way to pass such a name would be to add quotes;

docker stack deploy -c- foo <<EOF
version: "3.0"
services:
  "app.test_1":
    image: redis
EOF

But of course, that would still return the daemon error (as expected);

Creating network foo_default
Creating service foo_app.test_1
failed to create service foo_app.test_1: Error response from daemon: rpc error: code = InvalidArgument desc = name must be valid as a DNS name component

[lifubang]

The correct way to pass such a name would be to add quotes;

@thaJeztah if there were no ${APP_NOFILE}, everything will be OK. We don't need to add quotes.

But if there is ${APP_NOFILE}, docker cli needs to check the type of ulimits.nofile.soft, it will raise an incorrect error.

APP_NOFILE=1 build/docker stack deploy -c ~/t1.yaml foo
services.app.test_1.ulimits.nofile.soft must be a integer
(but APP_NOFILE is already a integer).

Even we add quotes, it raise the same incorrect error.