[Fuego] [PATCH 02/16] Mount fuego-rw/ro/core into the fuego-under-test container

[Guilherme Campos Camargo]

This patch implements the necessary logic for mounting fuego-rw,
fuego-ro and fuego-core into fuego.

Given that the dockerd socket is shared between the host and the fuego
container, the mountpoints that are passed to the `docker create` call
need to be provided as full paths relative to the *host* (and not
relative to fuego, as would be expected if the docker daemons were
independent)

Signed-off-by: Guilherme Campos Camargo <guicc at profusion.mobi>
---
 engine/tests/Functional.fuegotest/test_run.py | 63 +++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/engine/tests/Functional.fuegotest/test_run.py b/engine/tests/Functional.fuegotest/test_run.py
index 96fcfb7..7eae056 100755
--- a/engine/tests/Functional.fuegotest/test_run.py
+++ b/engine/tests/Functional.fuegotest/test_run.py
@@ -173,12 +173,43 @@ class FuegoContainer:
         self.container = None
 
     def setup_docker(self):
+        def this_container_id():
+            with open('/proc/self/cgroup', 'rt') as f:
+                f_text = f.read()
+
+                if 'docker' not in f_text:
+                    return None
+
+                for c in self.docker_client.containers(quiet=True):
+                    if c['Id'] in f_text:
+                        return c['Id']
+
+                return None
+
+        def map_to_host(mounts, container_id):
+            host_mounts = self.docker_client.\
+                inspect_container(container_id)['Mounts']
+
+            for mount in mounts:
+                LOGGER.debug('  Trying to find %s mountpoint in the host', mount['source'])
+                for host_mount in host_mounts:
+                    if mount['source'].startswith(host_mount['Destination']):
+                        mount['source'] = mount['source'].\
+                            replace(host_mount['Destination'],
+                                    host_mount['Source'], 1)
+                        LOGGER.debug('    Found: %s', mount['source'])
+                        break
+                else:
+                    LOGGER.debug('    Not Found')
+                    mount['source'] = None
+
         cmd = './{} {}'.format(self.install_script, self.image_name)
         LOGGER.debug('Running \'%s\' to install the docker image. '
                      'This may take a while....', cmd)
         status = subprocess.call(cmd, shell=True)
         if status != 0:
             return None
+
         docker_client = docker.from_env()
         containers = docker_client.containers.list(
             all=True, filters={'name': self.container_name})
@@ -188,10 +219,42 @@ class FuegoContainer:
                 self.container_name)
             containers[0].remove(force=True)
 
+        mounts = [
+            {'source': os.path.abspath('./fuego-rw'),
+             'destination':  '/fuego-rw',
+             'readonly': False,
+             },
+            {'source': os.path.abspath('./fuego-ro'),
+             'destination':  '/fuego-ro',
+             'readonly': True,
+             },
+            {'source': os.path.abspath('../fuego-core'),
+             'destination':  '/fuego-core',
+             'readonly': True,
+             },
+        ]
+
+        our_id = this_container_id()
+
+        if our_id:
+            LOGGER.debug('Running inside the Docker container %s', our_id)
+            map_to_host(mounts, our_id)
+        else:
+            LOGGER.debug('Not running inside a Docker container')
+
+        LOGGER.debug('Creating container with the following mountpoints:')
+        LOGGER.debug('  %s', mounts)
+
         container = docker_client.containers.create(
             self.image_name,
             stdin_open=True, tty=True, network_mode='bridge',
+            mounts=[docker.types.Mount(m['destination'],
+                                       m['source'],
+                                       type='bind',
+                                       read_only=m['readonly'])
+                    for m in mounts],
             name=self.container_name, command='/bin/bash')
+
         LOGGER.debug('Container \'%s\' created', self.container_name)
         return container
 
-- 
2.16.2