What started out as a simple PR to remove the "Readonly" column became an
adventure to add a proper type for a "View" snapshot. The short story here is
that we now get the following output:
```
$ sudo ctr snapshot ls
ID PARENT KIND
sha256:08c2295a7fa5c220b0f60c994362d290429ad92f6e0235509db91582809442f3 Committed
testing4 sha256:08c2295a7fa5c220b0f60c994362d290429ad92f6e0235509db91582809442f3 Active
```
In pursuing this output, it was found that the idea of having "readonly" as an
attribute on all snapshots was redundant. For committed, they are always
readonly, as they are not accessible without an active snapshot. For active
snapshots that were views, we'd have to check the type before interpreting
"readonly". With this PR, this is baked fully into the kind of snapshot. When
`Snapshotter.View` is called, the kind of snapshot is `KindView`, and the
storage system reflects this end to end.
Unfortunately, this will break existing users. There is no migration, so they
will have to wipe `/var/lib/containerd` and recreate everything. However, this
is deemed worthwhile at this point, as we won't have to judge validity of the
"Readonly" field when new snapshot types are added.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Since we now have a common set of error definitions, mapped to existing
error codes, we no longer need the specialized error codes used for
interaction with linux processes. The main issue was that string
matching was being used to map these to useful error codes. With this
change, we use errors defined in the `errdefs` package, which map
cleanly to GRPC error codes and are recoverable on either side of the
request.
The main focus of this PR was in removin these from the shim. We may
need follow ups to ensure error codes are preserved by the `Tasks`
service.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Update list content command to support filters
Add label subcommand to content in dist tool to update labels
Add uncompressed label on unpack
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
e.g. dist pull --snapshotter btrfs ...; ctr run --snapshotter btrfs ...
(empty string defaults for overlayfs)
Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Move content status to list statuses and add single status
to interface.
Updates API to support list statuses and status
Updates snapshot key creation to be generic
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
The primary feature we get with this PR is support for filters and
labels on the image metadata store. In the process of doing this, the
conventions for the API have been converged between containers and
images, providing a model for other services.
With images, `Put` (renamed to `Update` briefly) has been split into a
`Create` and `Update`, allowing one to control the behavior around these
operations. `Update` now includes support for masking fields at the
datastore-level across both the containers and image service. Filters
are now just string values to interpreted directly within the data
store. This should allow for some interesting future use cases in which
the datastore might use the syntax for more efficient query paths.
The containers service has been updated to follow these conventions as
closely as possible.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Allow plugins to be mapped and returned by their ID.
Add skip plugin to allow plugins to decide whether they should
be loaded.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
Now that we have most of the services required for use with containerd,
it was found that common patterns were used throughout services. By
defining a central `errdefs` package, we ensure that services will map
errors to and from grpc consistently and cleanly. One can decorate an
error with as much context as necessary, using `pkg/errors` and still
have the error mapped correctly via grpc.
We make a few sacrifices. At this point, the common errors we use across
the repository all map directly to grpc error codes. While this seems
positively crazy, it actually works out quite well. The error conditions
that were specific weren't super necessary and the ones that were
necessary now simply have better context information. We lose the
ability to add new codes, but this constraint may not be a bad thing.
Effectively, as long as one uses the errors defined in `errdefs`, the
error class will be mapped correctly across the grpc boundary and
everything will be good. If you don't use those definitions, the error
maps to "unknown" and the error message is preserved.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
These rpcs only return pids []uint32 so should be named that way in
order to have other rpcs that list Processes such as Exec'd processes.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
A few days ago, we added validation for namespaces. We've decided to
expand these naming rules to include containers. To facilitate this, a
common package `identifiers` now provides a common validation area.
These rules will be extended to apply to task identifiers, snapshot keys
and other areas where user-provided identifiers may be used.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This moves the shim's API and protos out of the containerd services
package and into the linux runtime package. This is because the shim is
an implementation detail of the linux runtime that we have and it is not
a containerd user facing api.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
To simplify use of types, we have consolidate the packages for the mount
and descriptor protobuf types into a single Go package. We also drop the
versioning from the type packages, as these types will remain the same
between versions.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
When using events, it was found to be fairly unwieldy with a number of
extra packages. For the most part, when interacting with the events
service, we want types of the same version of the service. This has been
accomplished by moving all events types into the events package.
In addition, several fixes to the way events are marshaled have been
included. Specifically, we defer to the protobuf type registration
system to assemble events and type urls, with a little bit sheen on top
of add a containerd.io oriented namespace.
This has resulted in much cleaner event consumption and has removed the
reliance on error prone type urls, in favor of concrete types.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This allow returning a more meaningful message when a request context
doesn't hold a namespace.
Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: update events package to include emitter and use envelope proto
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: add events service
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: enable events service and update ctr events to use events service
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
event listeners
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: helper func for emitting in services
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: improved cli for containers and tasks
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
create event envelope with poster
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: introspect event data to use for type url
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: use pb encoding; add event types
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: instrument content and snapshot services with events
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: instrument image service with events
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: instrument namespace service with events
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: add namespace support
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: only send events from namespace requested from client
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
events: switch to go-events for broadcasting
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
These interfaces allow us to preserve both the checking of error "cause"
as well as messages returned from the gRPC API so that the client gets
full error reason instead of a default "metadata: not found" in the case
of a missing image.
Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
We need a separate API for handing the exit status and deletion of
Exec'd processes to make sure they are properly cleaned up within the
shim and daemon.
Fixes#973
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Updates content service to handle lock errors and return
them to the client. The client remote handler has been
updated to retry when a resource is locked until the
resource is unlocked or the expected resource exists.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
To support multi-tenancy, containerd allows the collection of metadata
and runtime objects within a heirarchical storage primitive known as
namespaces. Data cannot be shared across these namespaces, unless
allowed by the service. This allows multiple sets of containers to
managed without interaction between the clients that management. This
means that different users, such as SwarmKit, K8s, Docker and others can
use containerd without coordination. Through labels, one may use
namespaces as a tool for cleanly organizing the use of containerd
containers, including the metadata storage for higher level features,
such as ACLs.
Namespaces
Namespaces cross-cut all containerd operations and are communicated via
context, either within the Go context or via GRPC headers. As a general
rule, no features are tied to namespace, other than organization. This
will be maintained into the future. They are created as a side-effect of
operating on them or may be created manually. Namespaces can be labeled
for organization. They cannot be deleted unless the namespace is empty,
although we may want to make it so one can clean up the entirety of
containerd by deleting a namespace.
Most users will interface with namespaces by setting in the
context or via the `CONTAINERD_NAMESPACE` environment variable, but the
experience is mostly left to the client. For `ctr` and `dist`, we have
defined a "default" namespace that will be created up on use, but there
is nothing special about it. As part of this PR we have plumbed this
behavior through all commands, cleaning up context management along the
way.
Namespaces in Action
Namespaces can be managed with the `ctr namespaces` subcommand. They
can be created, labeled and destroyed.
A few commands can demonstrate the power of namespaces for use with
images. First, lets create a namespace:
```
$ ctr namespaces create foo mylabel=bar
$ ctr namespaces ls
NAME LABELS
foo mylabel=bar
```
We can see that we have a namespace `foo` and it has a label. Let's pull
an image:
```
$ dist pull docker.io/library/redis:latest
docker.io/library/redis:latest: resolved |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d45bc46b48e45e8c72c41aedd2a173bcc7f1ea4084a8fcfc5251b1da2a09c0b6: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:5b690bc4eaa6434456ceaccf9b3e42229bd2691869ba439e515b28fe1a66c009: done |++++++++++++++++++++++++++++++++++++++|
config-sha256:a858478874d144f6bfc03ae2d4598e2942fc9994159f2872e39fae88d45bd847: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:4cdd94354d2a873333a205a02dbb853dd763c73600e0cf64f60b4bd7ab694875: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:10a267c67f423630f3afe5e04bbbc93d578861ddcc54283526222f3ad5e895b9: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:c54584150374aa94b9f7c3fbd743adcff5adead7a3cf7207b0e51551ac4a5517: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d1f9221193a65eaf1b0afc4f1d4fbb7f0f209369d2696e1c07671668e150ed2b: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:71c1f30d820f0457df186531dc4478967d075ba449bd3168a3e82137a47daf03: done |++++++++++++++++++++++++++++++++++++++|
elapsed: 0.9 s total: 0.0 B (0.0 B/s)
INFO[0000] unpacking rootfs
INFO[0000] Unpacked chain id: sha256:41719840acf0f89e761f4a97c6074b6e2c6c25e3830fcb39301496b5d36f9b51
```
Now, let's list the image:
```
$ dist images ls
REF TYPE DIGEST SIZE
docker.io/library/redis:latest application/vnd.docker.distribution.manifest.v2+json sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf 72.7 MiB
```
That looks normal. Let's list the images for the `foo` namespace and see
this in action:
```
$ CONTAINERD_NAMESPACE=foo dist images ls
REF TYPE DIGEST SIZE
```
Look at that! Nothing was pulled in the namespace `foo`. Let's do the
same pull:
```
$ CONTAINERD_NAMESPACE=foo dist pull docker.io/library/redis:latest
docker.io/library/redis:latest: resolved |++++++++++++++++++++++++++++++++++++++|
manifest-sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d45bc46b48e45e8c72c41aedd2a173bcc7f1ea4084a8fcfc5251b1da2a09c0b6: done |++++++++++++++++++++++++++++++++++++++|
config-sha256:a858478874d144f6bfc03ae2d4598e2942fc9994159f2872e39fae88d45bd847: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:4cdd94354d2a873333a205a02dbb853dd763c73600e0cf64f60b4bd7ab694875: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:c54584150374aa94b9f7c3fbd743adcff5adead7a3cf7207b0e51551ac4a5517: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:71c1f30d820f0457df186531dc4478967d075ba449bd3168a3e82137a47daf03: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:d1f9221193a65eaf1b0afc4f1d4fbb7f0f209369d2696e1c07671668e150ed2b: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:10a267c67f423630f3afe5e04bbbc93d578861ddcc54283526222f3ad5e895b9: done |++++++++++++++++++++++++++++++++++++++|
layer-sha256:5b690bc4eaa6434456ceaccf9b3e42229bd2691869ba439e515b28fe1a66c009: done |++++++++++++++++++++++++++++++++++++++|
elapsed: 0.8 s total: 0.0 B (0.0 B/s)
INFO[0000] unpacking rootfs
INFO[0000] Unpacked chain id: sha256:41719840acf0f89e761f4a97c6074b6e2c6c25e3830fcb39301496b5d36f9b51
```
Wow, that was very snappy! Looks like we pulled that image into out
namespace but didn't have to download any new data because we are
sharing storage. Let's take a peak at the images we have in `foo`:
```
$ CONTAINERD_NAMESPACE=foo dist images ls
REF TYPE DIGEST SIZE
docker.io/library/redis:latest application/vnd.docker.distribution.manifest.v2+json sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf 72.7 MiB
```
Now, let's remove that image from `foo`:
```
$ CONTAINERD_NAMESPACE=foo dist images rm
docker.io/library/redis:latest
```
Looks like it is gone:
```
$ CONTAINERD_NAMESPACE=foo dist images ls
REF TYPE DIGEST SIZE
```
But, as we can see, it is present in the `default` namespace:
```
$ dist images ls
REF TYPE DIGEST SIZE
docker.io/library/redis:latest application/vnd.docker.distribution.manifest.v2+json sha256:548a75066f3f280eb017a6ccda34c561ccf4f25459ef8e36d6ea582b6af1decf 72.7 MiB
```
What happened here? We can tell by listing the namespaces to get a
better understanding:
```
$ ctr namespaces ls
NAME LABELS
default
foo mylabel=bar
```
From the above, we can see that the `default` namespace was created with
the standard commands without the environment variable set. Isolating
the set of shared images while sharing the data that matters.
Since we removed the images for namespace `foo`, we can remove it now:
```
$ ctr namespaces rm foo
foo
```
However, when we try to remove the `default` namespace, we get an error:
```
$ ctr namespaces rm default
ctr: unable to delete default: rpc error: code = FailedPrecondition desc = namespace default must be empty
```
This is because we require that namespaces be empty when removed.
Caveats
- While most metadata objects are namespaced, containers and tasks may
exhibit some issues. We still need to move runtimes to namespaces and
the container metadata storage may not be fully worked out.
- Still need to migrate content store to metadata storage and namespace
the content store such that some data storage (ie images).
- Specifics of snapshot driver's relation to namespace needs to be
worked out in detail.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Clarify logic that extra data is stored when the target
buffer is full. Existing logic allows for extra data to
be stored even when more data will be read into buffer
when the remaining space is less than what was copied
from the last receive.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
This allows attach of existing fifos to be done without any information
stored on the client side.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
The implementations for the storage of metadata have been merged into a
single metadata package where they can share storage primitives and
techniques. The is a requisite for the addition of namespaces, which
will require a coordinated layout for records to be organized by
namespace.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Working from feedback on the existing implementation, we have now
introduced a central metadata object to represent the lifecycle and pin
the resources required to implement what people today know as
containers. This includes the runtime specification and the root
filesystem snapshots. We also allow arbitrary labeling of the container.
Such provisions will bring the containerd definition of container closer
to what is expected by users.
The objects that encompass today's ContainerService, centered around the
runtime, will be known as tasks. These tasks take on the existing
lifecycle behavior of containerd's containers, which means that they are
deleted when they exit. Largely, there are no other changes except for
naming.
The `Container` object will operate purely as a metadata object. No
runtime state will be held on `Container`. It only informs the execution
service on what is required for creating tasks and the resources in use
by that container. The resources referenced by that container will be
deleted when the container is deleted, if not in use. In this sense,
users can create, list, label and delete containers in a similar way as
they do with docker today, without the complexity of runtime locks that
plagues current implementations.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This moves both the Mount type and mountinfo into a single mount
package.
This also opens up the root of the repo to hold the containerd client
implementation.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Update go-runc to 49b2a02ec1ed3e4ae52d30b54a291b75
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Add shim to restore creation
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Keep checkpoint path in service
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Add C/R to non-shim build
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Checkpoint rw and image
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Pause container on bind checkpoints
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Return dump.log in error on checkpoint failure
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Pause container for checkpoint
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Update runc to 639454475cb9c8b861cc599f8bcd5c8c790ae402
For checkpoint into to work you need runc version
639454475cb9c8b861cc599f8bcd5c8c790ae402 + and criu 3.0 as this is what
I have been testing with.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Move restore behind create calls
This remove the restore RPCs in favor of providing the checkpoint
information to the `Create` calls of a container. If provided, the
container will be created/restored from the checkpoint instead of an
existing container.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Regen protos after rebase
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This adds support for signalling a container process by pid.
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
make Ps more extensible
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
ps: windows support
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
Remove rootfs service in place of snapshot service. Adds
diff service for extracting and creating diffs. Diff
creation is not yet implemented. This service allows
pulling or creating images without needing root access to
mount. Additionally in the future this will allow containerd
to ensure extractions happen safely in a chroot if needed.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
The split between provider and ingester was a long standing division
reflecting the client-side use cases. For the most part, we were
differentiating these for the algorithms that operate them, but it made
instantation and use of the types challenging. On the server-side, this
distinction is generally less important. This change unifies these types
and in the process we get a few benefits.
The first is that we now completely access the content store over GRPC.
This was the initial intent and we have now satisfied this goal
completely. There are a few issues around listing content and getting
status, but we resolve these with simple streaming and regexp filters.
More can probably be done to polish this but the result is clean.
Several other content-oriented methods were polished in the process of
unification. We have now properly seperated out the `Abort` method to
cancel ongoing or stalled ingest processes. We have also replaced the
`Active` method with a single status method.
The transition went extremely smoothly. Once the clients were updated to
use the new methods, every thing worked as expected on the first
compile.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This adds pause and unpause to containerd's execution service and the
same commands to the `ctr` client.
Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
This allows one to edit content in the content store with their favorite
editor. It is as simple as this:
```console
$ dist content edit sha256:58e1a1bb75db1b5a24a462dd5e2915277ea06438c3f105138f97eb53149673c4
```
The above will pop up your $EDITOR, where you can make changes to the content.
When you are done, save and the new version will be added to the content store.
The digest of the new content will be printed to stdout:
```console
sha256:247f30ac320db65f3314b63b908a3aeaac5813eade6cabc9198b5883b22807bc
```
We can then retrieve the content quite easily:
```console
$ dist content get sha256:247f30ac320db65f3314b63b908a3aeaac5813eade6cabc9198b5883b22807bc
{
"schemaVersion": 2,
"mediaType": "application/vnd.docker.distribution.manifest.v2+json",
"config": {
"mediaType": "application/vnd.docker.container.image.v1+json",
"size": 1278,
"digest": "sha256:4a415e3663882fbc554ee830889c68a33b3585503892cc718a4698e91ef2a526"
},
"annotations": {},
"layers": [
{
"mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
"size": 1905270,
"digest": "sha256:627beaf3eaaff1c0bc3311d60fb933c17ad04fe377e1043d9593646d8ae3bfe1"
}
]
}
```
In this case, an annotations field was added to the original manifest.
While this implementation is very simple, we can add all sorts of validation
and tooling to allow one to edit images inline. Coupled with declaring the
mediatype, we could return specific errors that can allow a user to craft
valid, working modifications to images for testing and profit.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Add functionality for restoring containers after containerd dies and is
restarted with terminated shims.
This ensures that on restore, if a container no longer has a running
shim, containerd will kill and cleanup the container.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
For some reason, when I wrote this, I forgot about the `View` and
`Update` helpers on boltdb. These are now used and makes the code much
easier to follow.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
With this changeset, image store access is now moved to completely
accessible over GRPC. No clients manipulate the image store database
directly and the GRPC client is fully featured. The metadata database is
now managed by the daemon and access coordinated via services.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Server and Client images of the image store are now provided. We have
created an image metadata interface and converted the bolt functions to
implement that interface over an transaction. A remote client
implementation is provided that implements the same interface.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This is a first pass at the metadata required for supporting an image
store. We use a shallow approach to the problem, allowing this
component to centralize the naming. Resources for this image can then be
"snowballed" in for actual implementations. This is better understood
through example.
Let's take pull. One could register the name "docker.io/stevvooe/foo" as
pointing at a particular digest. When instructed to pull or fetch, the
system will notice that no components of that image are present locally.
It can then recursively resolve the resources for that image and fetch
them into the content store. Next time the instruction is issued, the
content will be present so no action will be taken.
Another example is preparing the rootfs. The requirements for a rootfs
can be resolved from a name. These "diff ids" will then be compared with
what is available in the snapshot manager. Any parts of the rootfs, such
as a layer, that isn't available in the snapshotter can be unpacked.
Once this process is satisified, the image will be runnable as a
container.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
The service can use the snapshotter directly to get the rootfs.
Removed debug line for mount response.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
The message was defined but the method was returning empty, plumb through the
result from the shim layer.
Compile tested only.
Signed-off-by: Ian Campbell <ian.campbell@docker.com>
To make restarting after failed pull less racy, we define `Truncate(size
int64) error` on `content.Writer` for the zero offset. Truncating a
writer will dump any existing data and digest state and start from the
beginning. All subsequent writes will start from the zero offset.
For the service, we support this by defining the behavior for a write
that changes the offset. To keep this narrow, we only support writes out
of order at the offset 0, which causes the writer to dump existing data
and reset the local hash.
This makes restarting failed pulls much smoother when there was a
previously encountered error and the source doesn't support arbitrary
seeks or reads at arbitrary offsets. By allowing this to be done while
holding the write lock on a ref, we can restart the full download
without causing a race condition.
Once we implement seeking on the `io.Reader` returned by the fetcher,
this will be less useful, but it is good to ensure that our protocol
properly supports this use case for when streaming is the only option.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Allow deletion of content over the GRPC interface. For now, we are going
with a model that conducts reference management outside of the content
store, in the metadata store but this design is valid either way.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
For clients which only want to know about one container this is simpler than
searching the result of execution.List.
Signed-off-by: Ian Campbell <ian.campbell@docker.com>
After implementing pull, a few changes are required to the content store
interface to make sure that the implementation works smoothly.
Specifically, we work to make sure the predeclaration path for digests
works the same between remote and local writers. Before, we were
hesitent to require the the size and digest up front, but it became
clear that having this provided significant benefit.
There are also several cleanups related to naming. We now call the
expected digest `Expected` consistently across the board and `Total` is
used to mark the expected size.
This whole effort comes together to provide a very smooth status
reporting workflow for image pull and push. This will be more obvious
when the bulk of pull code lands.
There are a few other changes to make `content.WriteBlob` more broadly
useful. In accordance with addition for predeclaring expected size when
getting a `Writer`, `WriteBlob` now supports this fully. It will also
resume downloads if provided an `io.Seeker` or `io.ReaderAt`. Coupled
with the `httpReadSeeker` from `docker/distribution`, we should only be
a lines of code away from resumable downloads.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Add registration for more subsystems via plugins
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
Move content service to separate package
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
