When a manifest is deleted by digest, look up the referenced tags in the tag
store and remove all associations.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
Add a generic Manifest interface to represent manifests in the registry and
remove references to schema specific manifests.
Add a ManifestBuilder to construct Manifest objects. Concrete manifest builders
will exist for each manifest type and implementations will contain manifest
specific data used to build a manifest.
Remove Signatures() from Repository interface.
Signatures are relevant only to schema1 manifests. Move access to the signature
store inside the schema1 manifestStore. Add some API tests to verify
signature roundtripping.
schema1
-------
Change the way data is stored in schema1.Manifest to enable Payload() to be used
to return complete Manifest JSON from the HTTP handler without knowledge of the
schema1 protocol.
tags
----
Move tag functionality to a seperate TagService and update ManifestService
to use the new interfaces. Implement a driver based tagService to be backward
compatible with the current tag service.
Add a proxyTagService to enable the registry to get a digest for remote manifests
from a tag.
manifest store
--------------
Remove revision store and move all signing functionality into the signed manifeststore.
manifest registration
---------------------
Add a mechanism to register manifest media types and to allow different manifest
types to be Unmarshalled correctly.
client
------
Add ManifestServiceOptions to client functions to allow tags to be passed into Put and
Get for building correct registry URLs. Change functional arguments to be an interface type
to allow passing data without mutating shared state.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
Signed-off-by: Richard Scothern <richard.scothern@docker.com>
tarsum is not actually used by the registry. Remove support for it.
Convert numerous uses in unit tests to SHA256.
Update docs to remove mentions of tarsums (which were often inaccurate).
Remove tarsum dependency.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
The current implementation of digest.FromBytes returns an error. This
error can never be non-nil, but its presence in the function signature
means each call site needs error handling code for an error that is
always nil.
I verified that none of the hash.Hash implementations in the standard
library can return an error on Write. Nor can any of the hash.Hash
implementations vendored in distribution.
This commit changes digest.FromBytes not to return an error. If Write
returns an error, it will panic, but as discussed above, this should
never happen.
This commit also avoids using a bytes.Reader to feed data into the hash
function in FromBytes. This makes the hypothetical case that would panic
a bit more explicit, and should also be more performant.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
contains equal length History and FSLayer arrays.
This is required to prevent malformed manifests being put to the registry and
failing external verification checks.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
To ensure that we only unmarshal the verified payload into the contained
manifest, we first copy the entire incoming buffer into Raw and then unmarshal
only the Payload portion of the incoming bytes. If the contents is later
verified, the caller can then be sure that the contents of the Manifest fields
can be trusted.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This allows the administrator to specify an externally-reachable URL for
the registry. It takes precedence over the X-Forwarded-Proto and
X-Forwarded-Host headers, and the hostname in the request.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Add "readonly" under the storage/maintenance section. When this is set
to true, uploads and deletions will return 503 Service Unavailable
errors.
Document the parameter and add some unit testing.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
By adding WithVersion to the context package, we can simplify context setup in
the application. This avoids some odd bugs where instantiation order can lead
to missing instance.id or version from log messages.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
As we begin our march towards multi-arch, we must prepare for the reality of
multiple manifest schemas. This is the beginning of a set of changes to
facilitate this. We are both moving this package into its target position where
it may live peacefully next to other manfiest versions.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Also, add timeout and status code parameters to the HTTP checker, and
remove the threshold parameter for the file checker.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Update docs.
Change health_test.go tests to create their own registries and register
the checks there. The tests now call CheckStatus directly instead of
polling the HTTP handler, which returns results from the default
registry.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Add default storagedriver health check to example configuration files
with parameters matching the previous hardcoded configuration.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Add a section to the config file called "health". Within this section,
"filecheckers" and "httpcheckers" list checks to run. Each check
specifies a file or URI, a time interval for the check, and a threshold
specifying how many times the check must fail to reach an unhealthy
state.
Document the new options in docs/configuration.md.
Add unit testing for both types of checkers. Add an UnregisterAll
function in the health package to support the unit tests, and an
Unregister function for consistency with Register.
Fix a string conversion problem in the health package's HTTP checker.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Clean up calling convention for NewRegistryWithDriver to use functional
arguments.
This is a first step towards the refactor described in #215. I plan to
add additional options in the process of moving configurable items from
the App structure to the registry structure.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
A change in #763 to address review comments caused problems. Originally,
instrumentedResponseWriter implemented the CloseNotifier interface, and
would panic if it was wrapping something that did not implement that
interface. This was split into a separate instrumentedResponseWriterCN
type that implements CloseNotifier, so there's a fallback if
instrumentedResponseWriter ever needs to wrap something that does not
implement this interface.
instrumentedResponseWriter's Value method would end up upcasting either
type back to instrumentedResponseWriter, which does not implement the
interface. In effect, instrumentedResponseWriterCN was never visible to
the handler.
This fixes the problem by implementing a wrapper Value method for
instrumentedResponseWriterCN.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Change checkResponse to only expect the configured
X-Content-Type-Options header if it doesn't receive a 405 error, which
means the handler isn't registered for that method.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
The example configuration files add X-Content-Type-Options: nosniff.
Add coverage in existing registry/handlers unit tests.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
distribution errors. Fill in missing checks for mutations on a registry pull-through
cache. Add unit tests and update documentation.
Also, give v2.ErrorCodeUnsupported an HTTP status code, previously it was
defaulting to 500, now its 405 Method Not Allowed.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
Several error codes are generally useful but tied to the v2 specification
definitions. This change moves these error code definitions into the common
package for use by the health package, which is not tied to the v2 API.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
To ensure the ensure the web application is properly operating, we've added a
periodic health check for the storage driver. If the health check fails three
times in a row, the registry will serve 503 response status for any request
until the condition is resolved. The condition is reported in the response body
and via the /debug/health endpoint.
To ensure that all drivers will properly operate with this health check, a
function has been added to the driver testsuite.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Instead, provide a variant of instrumentedResponseWriter that does not
implement CloseNotifier, and use that when necessary. In
copyFullPayload, log instead of panicing when we encounter something
that doesn't implement CloseNotifier.
This is more complicated than I'd like, but it's necessary because
instrumentedResponseWriter must not embed CloseNotifier unless there's
really a CloseNotifier to embed.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
with a new `proxy` section in the configuration file.
Create a new registry type which delegates storage to a proxyBlobStore
and proxyManifestStore. These stores will pull through data if not present
locally. proxyBlobStore takes care not to write duplicate data to disk.
Add a scheduler to cleanup expired content. The scheduler runs as a background
goroutine. When a blob or manifest is pulled through from the remote registry,
an entry is added to the scheduler with a TTL. When the TTL expires the
scheduler calls a pre-specified function to remove the fetched resource.
Add token authentication to the registry middleware. Get a token at startup
and preload the credential store with the username and password supplied in the
config file.
Allow resumable digest functionality to be disabled at runtime and disable
it when the registry is a pull through cache.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
The response code isn't actually sent to the client, because the
connection has already closed by this point. But it causes the status
code to appear as 499 in the logs instead of 0.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
When a client disconnects without completing a HTTP request, we were
attempting to process the partial request, which usually leads to a 400
error. These errors can pollute the logs and make it more difficult to
track down real bugs.
This change uses CloseNotifier to detect disconnects. In combination
with checking Content-Length, we can detect a disconnect before sending
the full payload, and avoid logging a 400 error.
This logic is only applied to PUT, POST, and PATCH endpoints, as these
are the places where disconnects during a request are most likely to
happen.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
includes the http response.
When debugging non-successful registry requests this will place
the error details and http status fields in the same log line
giving easier visibility to what error occured in the request.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
Log a warning if the registry generates its own secret.
Update configuration doc, and remove the default secret from the
development config file.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This passed in the #744 before merge, but apparently the test changed
since the PR was created in ways that led to a new failures.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Storage drivers can implement a method called URLFor which can return a direct
url for a given path. The functionality allows the registry to direct clients
to download content directly from the backend storage. This is commonly used
with s3 and cloudfront. Under certain conditions, such as when the registry is
not local to the backend, these redirects can hurt performance and waste
incoming bandwidth on pulls. This feature addition allows one to disable this
feature, if required.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Conflicts:
configuration/configuration.go
registry/handlers/app.go
registry/storage/catalog_test.go
registry/storage/manifeststore_test.go
registry/storage/registry.go
Implement the delete API by implementing soft delete for layers
and blobs by removing link files and updating the blob descriptor
cache. Deletion is configurable - if it is disabled API calls
will return an unsupported error.
We invalidate the blob descriptor cache by changing the linkedBlobStore's
blobStatter to a blobDescriptorService and naming it blobAccessController.
Delete() is added throughout the relevant API to support this functionality.
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
Because the logger was incorrectly replaced while adding hooks, log output did
not include the version and instance ids. The main issue was the the
logrus.Entry was replaced with the logger, which included no context. Replacing
the logger on the context is not necessary when configuring hooks since we are
configuring the contexts logger directly.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This removes the erroneous http.Handler interface in favor a simple SetHeaders
method that only operattes on the response. Several unnecessary uses of pointer
types were also fixed up.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This change removes the Catalog Service and replaces it with a more
simplistic Repositories() method for obtaining a catalog of all
repositories. The Repositories method takes a pre-allocated slice
and fills it up to the size of the slice and returns the amount
filled. The catalog is returned lexicographically and will start
being filled from the last entry passed to Repositories(). If there
are no more entries to fill, io.EOF will be returned.
Signed-off-by: Patrick Devine <patrick.devine@docker.com>
Conflicts:
registry/client/repository.go
registry/handlers/api_test.go
This change adds a basic catalog endpoint to the API, which returns a list,
or partial list, of all of the repositories contained in the registry. Calls
to this endpoint are somewhat expensive, as every call requires walking a
large part of the registry.
Instead, to maintain a list of repositories, you would first call the catalog
endpoint to get an initial list, and then use the events API to maintain
any future repositories.
Signed-off-by: Patrick Devine <patrick.devine@docker.com>
An error level log is already produced within app.authorized() if an
actual unexpected error occurs during authorization, so this warning
level log remains for auditability purposes, but should not be
considered an error condition.
Addresses #704
Signed-off-by: Brian Bland <brian.bland@docker.com>
This changeset provides a common http handler for serving errcodes. This should
unify http responses across webservices in the face of errors.
Several type assertions have been added, as well, to ensure the error interface
is implemented.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
See: 3ea67df373/registry/handlers/app.go (L498)
Per the comment on line 498, this moves the logic of setting the http
status code into the serveJSON func, leaving the auth.Challenge.ServeHTTP()
func to just set the auth challenge header.
Signed-off-by: Doug Davis <dug@us.ibm.com>
After consideration, the basic authentication implementation has been
simplified to only support bcrypt entries in an htpasswd file. This greatly
increases the security of the implementation by reducing the possibility of
timing attacks and other problems trying to detect the password hash type.
Also, the htpasswd file is only parsed at startup, ensuring that the file can
be edited and not effect ongoing requests. Newly added passwords take effect on
restart. Subsequently, password hash entries are now stored in a map.
Test cases have been modified accordingly.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This PR is for issue of "email after registry webapp panic" #41, improving my
previous design (closed).
It use self setting up hooks, to catch panic in web application.
And, send email in hooks handle directly, to no use new http server and
handler.
Signed-off-by: xiekeyang <keyangxie@126.com>
To make the definition of supported digests more clear, we have refactored the
digest package to have a special Algorithm type. This represents the digest's
prefix and we associated various supported hash implementations through
function calls.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
The change relies on a refactor of the upstream resumable sha256/sha512 package
that opts to register implementations with the standard library. This allows
the resumable support to be detected where it matters, avoiding unnecessary and
complex code. It also ensures that consumers of the digest package don't need
to depend on the forked sha implementations.
We also get an optimization with this change. If the size of data written to a
digester is the same as the file size, we check to see if the digest has been
verified. This works if the blob is written and committed in a single request.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Ensure that clients can use the blob descriptor cache provider without needing
the redis package.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This PR refactors the blob service API to be oriented around blob descriptors.
Identified by digests, blobs become an abstract entity that can be read and
written using a descriptor as a handle. This allows blobs to take many forms,
such as a ReadSeekCloser or a simple byte buffer, allowing blob oriented
operations to better integrate with blob agnostic APIs (such as the `io`
package). The error definitions are now better organized to reflect conditions
that can only be seen when interacting with the blob API.
The main benefit of this is to separate the much smaller metadata from large
file storage. Many benefits also follow from this. Reading and writing has
been separated into discrete services. Backend implementation is also
simplified, by reducing the amount of metadata that needs to be picked up to
simply serve a read. This also improves cacheability.
"Opening" a blob simply consists of an access check (Stat) and a path
calculation. Caching is greatly simplified and we've made the mapping of
provisional to canonical hashes a first-class concept. BlobDescriptorService
and BlobProvider can be combined in different ways to achieve varying effects.
Recommend Review Approach
-------------------------
This is a very large patch. While apologies are in order, we are getting a
considerable amount of refactoring. Most changes follow from the changes to
the root package (distribution), so start there. From there, the main changes
are in storage. Looking at (*repository).Blobs will help to understand the how
the linkedBlobStore is wired. One can explore the internals within and also
branch out into understanding the changes to the caching layer. Following the
descriptions below will also help to guide you.
To reduce the chances for regressions, it was critical that major changes to
unit tests were avoided. Where possible, they are left untouched and where
not, the spirit is hopefully captured. Pay particular attention to where
behavior may have changed.
Storage
-------
The primary changes to the `storage` package, other than the interface
updates, were to merge the layerstore and blobstore. Blob access is now
layered even further. The first layer, blobStore, exposes a global
`BlobStatter` and `BlobProvider`. Operations here provide a fast path for most
read operations that don't take access control into account. The
`linkedBlobStore` layers on top of the `blobStore`, providing repository-
scoped blob link management in the backend. The `linkedBlobStore` implements
the full `BlobStore` suite, providing access-controlled, repository-local blob
writers. The abstraction between the two is slightly broken in that
`linkedBlobStore` is the only channel under which one can write into the global
blob store. The `linkedBlobStore` also provides flexibility in that it can act
over different link sets depending on configuration. This allows us to use the
same code for signature links, manifest links and blob links. Eventually, we
will fully consolidate this storage.
The improved cache flow comes from the `linkedBlobStatter` component
of `linkedBlobStore`. Using a `cachedBlobStatter`, these combine together to
provide a simple cache hierarchy that should streamline access checks on read
and write operations, or at least provide a single path to optimize. The
metrics have been changed in a slightly incompatible way since the former
operations, Fetch and Exists, are no longer relevant.
The fileWriter and fileReader have been slightly modified to support the rest
of the changes. The most interesting is the removal of the `Stat` call from
`newFileReader`. This was the source of unnecessary round trips that were only
present to look up the size of the resulting reader. Now, one must simply pass
in the size, requiring the caller to decide whether or not the `Stat` call is
appropriate. In several cases, it turned out the caller already had the size
already. The `WriterAt` implementation has been removed from `fileWriter`,
since it is no longer required for `BlobWriter`, reducing the number of paths
which writes may take.
Cache
-----
Unfortunately, the `cache` package required a near full rewrite. It was pretty
mechanical in that the cache is oriented around the `BlobDescriptorService`
slightly modified to include the ability to set the values for individual
digests. While the implementation is oriented towards caching, it can act as a
primary store. Provisions are in place to have repository local metadata, in
addition to global metadata. Fallback is implemented as a part of the storage
package to maintain this flexibility.
One unfortunate side-effect is that caching is now repository-scoped, rather
than global. This should have little effect on performance but may increase
memory usage.
Handlers
--------
The `handlers` package has been updated to leverage the new API. For the most
part, the changes are superficial or mechanical based on the API changes. This
did expose a bug in the handling of provisional vs canonical digests that was
fixed in the unit tests.
Configuration
-------------
One user-facing change has been made to the configuration and is updated in
the associated documentation. The `layerinfo` cache parameter has been
deprecated by the `blobdescriptor` cache parameter. Both are equivalent and
configuration files should be backward compatible.
Notifications
-------------
Changes the `notification` package are simply to support the interface
changes.
Context
-------
A small change has been made to the tracing log-level. Traces have been moved
from "info" to "debug" level to reduce output when not needed.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
- Set an Etag header
- Check If-None-Match and respond appropriately
- Set a Cache-Control header with a default of 1 week
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
- Ensures new uploads and resumed upload statuses always return an offset of 0. This allows future clients which support resumable upload to not attempt resumable upload on this version which does not support it.
- Add PATCH support for streaming data on upload.
- Add messaging to specification that PATCH with content range is currently not supported.
- Update PUT blob to only support full data or no data, no more last chunk messaging as it was not supported.
closes#470
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
- Change driver interface to take a context as its first argument
- Make newFileReader take a context as its first argument
- Make newFileWriter take a context as its first argument
- Make blobstore exists and delete take a context as a first argument
- Pass the layerreader's context to the storage layer
- Pass the app's context to purgeuploads
- Store the app's context into the blobstore (was previously null)
- Pass the trace'd context to the storage drivers
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
This adds a missing return statement. It is not strictly needed since if the
io.Copy fails, the Finish operation will fail. Currently, the client reports
both errors where this new code will correctly only report the io.Copy error.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
When the registry starts a background timer will periodically
scan the upload directories on the file system every 24 hours
and delete any files older than 1 week. An initial jitter
intends to avoid contention on the filesystem where multiple
registries with the same storage driver are started
simultaneously.
Ensure that the status is logged in the context by instantiating before the
request is routed to handlers. While this requires some level of hacking to
acheive, the result is that the context value of "http.request.status" is as
accurate as possible for each request.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Registry is intended to be used as a repository service than an abstract collection of repositories. Namespace better describes a collection of repositories retrievable by name.
The registry service serves any repository in the global scope.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
This moves the instance id out of the app so that it is associated with an
instantiation of the runtime. The instance id is stored on the background
context. This allows allow contexts using the main background context to
include an instance id for log messages. It also simplifies the application
slightly.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
For consistency with other systems, the redis and caching monitoring data has
been moved under the "registry" section in expvar. This ensures the entire
registry state is kept to a single section.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This allows one to better control the usage of the cache and turn it off
completely. The storage configuration module was modified to allow parameters
to be passed to just the storage implementation, rather than to the driver.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This changeset integrates the layer info cache with the registry webapp and
storage backend. The main benefit is to cache immutable layer meta data,
reducing backend roundtrips. The cache can be configured to use either redis or
an inmemory cache.
This provides massive performance benefits for HEAD http checks on layer blobs
and manifest verification.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Redis has been integrated with the web application for use with various
services. The configuraiton exposes connection details, timeouts and pool
parameters. Documentation has been updated accordingly.
A few convenience methods have been added to the context package to get loggers
with certain fields, exposing some missing functionality from logrus.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Convert middleware in the config to be a map of type->[]Middleware
Add support for registry & repository middleware.
Some naming updates as well.
Signed-off-by: Andy Goldstein <agoldste@redhat.com>
middleware concept.
This also breaks the dependency the storage package had on goamz
Signed-off-by: David Lawrence <david.lawrence@docker.com> (github: endophage)
This changeset implements immutable manifest references via the HTTP API. Most
of the changes follow from modifications to ManifestService. Once updates were
made across the repo to implement these changes, the http handlers were change
accordingly. The new methods on ManifestService will be broken out into a
tagging service in a later PR.
Unfortunately, due to complexities around managing the manifest tag index in an
eventually consistent manner, direct deletes of manifests have been disabled.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This changeset adds support for a header to identify docker upload uuids. This
id can be used as a key to manage local state for resumable uploads. The goal
is remove the necessity for a client to parse the url to get an upload uuid.
The restrictions for clients to use the location header are still strongly in
place.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
The method (Registry).Repository may now return an error. This is too allow
certain implementationt to validate the name or opt to not return a repository
under certain conditions.
In conjunction with this change, error declarations have been moved into a
single file in the distribution package. Several error declarations that had
remained in the storage package have been moved into distribution, as well. The
declarations for Layer and LayerUpload have also been moved into the main
registry file, as a result.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Since the notifications package is now decoupled from storage, we are moving it
to the root package.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
A Layer or LayerUpload should not be coupled with the containing repository.
Remove the Name method and correctly reference from the repository where
appropriate.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
After consideration, it has been decided that the interfaces defined in the
storage package provide a good base for interacting with various registry
instances. Whether interacting with a remote API or a local, on-disk registry,
these types have proved flexible. By moving them here, they can become the
central components of interacting with distribution components.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
After all of the perl refactoring, some import orderings were left asunder.
This commit corrects that.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
This change is slightly more complex than previous package maves in that the
package name changed. To address this, we simply always reference the package
driver as storagedriver to avoid compatbility issues with existing code. While
unfortunate, this can be cleaned up over time.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
The goal is to free up the distribution/registry package to include common
registry types. This moves the webapp definitions out of the way to allow for
this change in the future.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
