The -m/--mount option makes it possible to bind-mount volumes at runtime. The
volumes are declared in a local/docker-compose.tmp.yml file. The problem with
this approach is when we want to bind-mount a volume to a service which is
specific to the dev context. For instance: the "learning" service when the MFE
plugin is enabled.
In such a case, starting the service triggers a call to `docker-compose stop`
in the local context. This call fails because the "learning" service does not
exist in the local context. Note that this issue only seems to occur with
docker-compose v1.
To resolve this issue, we create two additional filters for
the dev context, which emulate the behaviour of the local context. With this approach, we convert the -m/--mount arguments right after they are parsed. Because they are parsed just once, we can get rid of the de-duplication logic initially introduced with the COMPOSE_CLI_MOUNTS context.
Close #711. Close also https://github.com/overhangio/tutor-mfe/issues/57.
In certain code paths, such as in `tutor local quickstart`,
`process_mount_points` is called more than once in the same process,
causing mounts to be added to `COMPOSE_LOCAL[_JOBS]_TMP` redundantly.
As a result, docker-compose[.jobs].tmp.yml was occasionally being
rendered with duplicate volume specifiers. Some versions of Docker
Compose ignored this; other versions warned or threw an error.
In order to make `process_mount_points` tolerant to being called
multiple times, we wrap its volume-adding callbacks within a new
hooks context. This allows us to clear said hooks context every
time `process_mount_points` is called, essentially making the
function idempotent.
Co-authored-by: Régis Behmo <regis@behmo.com>
`copyfrom` copies data from a container to the local filesystem. It's similar
to bindmount, but less clunky, and more intuitive. Also, it plays along great
with `--mount`. Eventually we'll just get rid of the `bindmount` command and
the `--volume` option.
The `--mount` option is available both with `tutor local`
and `tutor dev` commands. It allows users to easily bind-mount containers from
the host to containers. Yes, I know, we already provide that possibility with
the `bindmount` command and the `--volume=/path/` option. But these suffer from
the following drawbacks:
- They are difficult to understand.
- The "bindmount" command name does not make much sense.
- It's not convenient to mount an arbitrary folder from the host to multiple
containers, such as the many lms/cms containers (web apps, celery workers and
job runners).
To address this situation, we now recommend to make use of --mount:
1. `--mount=service1[,service2,...]:/host/path:/container/path`: manually mount
`/host/path` to `/container/path` in container "service1" (and "service2").
2. `--mount=/host/path`: use the new v1 plugin API to discover plugins that
will detect this option and select the right containers in which to bind-mount
volumes. This is really nifty...
Close https://github.com/overhangio/2u-tutor-adoption/issues/43
