The Container.State struct holds the container's state, and most of
its fields are expected to change dynamically. Some o these state-changes
are explicit, for example, setting the container to be "stopped". Other
state changes can be more explicit, for example due to the containers'
process exiting or being "OOM" killed by the kernel.
The distinction between explicit ("desired") state changes and "state"
("actual state") is sometimes vague; for some properties, we clearly
separated them, for example if a user requested the container to be
stopped or restarted, we store state in the Container object itself;
HasBeenManuallyStopped bool // used for unless-stopped restart policy
HasBeenManuallyRestarted bool `json:"-"` // used to distinguish restart caused by restart policy from the manual one
Other properties are more ambiguous. such as "HasBeenStartedBefore" and
"RestartCount", which are stored on the Container (and persisted to
disk), but may be more related to "actual" state, and likely should
not be persisted;
RestartCount int
HasBeenStartedBefore bool
Given that (per the above) concurrency must be taken into account, most
changes to the `container.State` struct should be protected; here's where
things get blurry. While the `State` type provides various accessor methods,
only some of them take concurrency into account; for example, [State.IsRunning]
and [State.GetPID] acquire a lock, whereas [State.ExitCodeValue] does not.
Even the (commonly used) [State.StateString] has no locking at all.
The way to handle this is error-prone; [container.State] contains a mutex,
and it's exported. Given that its embedded in the [container.Container]
struct, it's also exposed as an exported mutex for the container. The
assumption here is that by "merging" the two, the caller to acquire a lock
when either the container _or_ its state must be mutated. However, because
some methods on `container.State` handle their own locking, consumers must
be deeply familiar with the internals; if both changes to the `Container`
AND `Container.State` must be made. This gets amplified more as some
(exported!) methods, such as [container.SetRunning] mutate multiple fields,
but don't acquire a lock (so expect the caller to hold one), but their
(also exported) counterpart (e.g. [State.IsRunning]) do.
It should be clear from the above, that this needs some architectural
changes; a clearer separation between "desired" and "actual" state (opening
the potential to update the container's config without manually touching
its `State`), possibly a method to obtain a read-only copy of the current
state (for those querying state), and reviewing which fields belong where
(and should be persisted to disk, or only remain in memory).
This PR preserves the status quo; it makes no structural changes, other
than exposing where we access the container's state. Where previously the
State fields and methods were referred to as "part of the container"
(e.g. `ctr.IsRunning()` or `ctr.Running`), we now explicitly reference
the embedded `State` (`ctr.State.IsRunning`, `ctr.State.Running`).
The exception (for now) is the mutex, which is still referenced through
the embedded struct (`ctr.Lock()` instead of `ctr.State.Lock()`), as this
is (mostly) by design to protect the container, and what's in it (including
its `State`).
[State.IsRunning]: c4afa77157/daemon/container/state.go (L205-L209)
[State.GetPID]: c4afa77157/daemon/container/state.go (L211-L216)
[State.ExitCodeValue]: c4afa77157/daemon/container/state.go (L218-L228)
[State.StateString]: c4afa77157/daemon/container/state.go (L102-L131)
[container.State]: c4afa77157/daemon/container/state.go (L15-L23)
[container.Container]: c4afa77157/daemon/container/container.go (L67-L75)
[container.SetRunning]: c4afa77157/daemon/container/state.go (L230-L277)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
These comments were added to enforce using the correct import path for
our packages ("github.com/docker/docker", not "github.com/moby/moby").
However, when working in go module mode (not GOPATH / vendor), they have
no effect, so their impact is limited.
Remove these imports in preparation of migrating our code to become an
actual go module.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Close archive when context is done - this makes the cancellation
actually stop the export instead of continuing it regardless if the
client still expects the data.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
With `RWLayer` it's no longer necessary to define it for each image
service as it became a wrapper for the RWLayer's Mount and Unmount.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Change the persistent container metadata to store the whole platform
(as defined by OCI) instead of only the operating system.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Define consts for the Actions we use for events, instead of "ad-hoc" strings.
Having these consts makes it easier to find where specific events are triggered,
makes the events less error-prone, and allows documenting each Action (if needed).
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Now that the type of Container.BaseFS has been reverted to a string,
values can never implement the extractor or archiver interfaces. Rip out
the dead code to support archiving and unarchiving through those
interfcaes.
Signed-off-by: Cory Snider <csnider@mirantis.com>
Finish the refactor which was partially completed with commit
34536c498d, passing around IdentityMapping structs instead of pairs of
[]IDMap slices.
Existing code which uses []IDMap relies on zero-valued fields to be
valid, empty mappings. So in order to successfully finish the
refactoring without introducing bugs, their replacement therefore also
needs to have a useful zero value which represents an empty mapping.
Change IdentityMapping to be a pass-by-value type so that there are no
nil pointers to worry about.
The functionality provided by the deprecated NewIDMappingsFromMaps
function is required by unit tests to to construct arbitrary
IdentityMapping values. And the daemon will always need to access the
mappings to pass them to the Linux kernel. Accommodate these use cases
by exporting the struct fields instead. BuildKit currently depends on
the UIDs and GIDs methods so we cannot get rid of them yet.
Signed-off-by: Cory Snider <csnider@mirantis.com>
This removes some of the checks that were added in 0cba7740d4,
but should no longer be needed.
- `Daemon.create()`: fix the error message, which assumed it could only occur on Windows.
- `Daemon.cleanupContainer()`: no need to validate container platform to delete it.
- `Daemon.containerExport`: if a container was created, we should be able to
export it; no need to validate.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Previously only unpack operations were supported with chroot.
This adds chroot support for packing operations.
This prevents potential breakouts when copying data from a container.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
This implements chown support on Windows. Built-in accounts as well
as accounts included in the SAM database of the container are supported.
NOTE: IDPair is now named Identity and IDMappings is now named
IdentityMapping.
The following are valid examples:
ADD --chown=Guest . <some directory>
COPY --chown=Administrator . <some directory>
COPY --chown=Guests . <some directory>
COPY --chown=ContainerUser . <some directory>
On Windows an owner is only granted the permission to read the security
descriptor and read/write the discretionary access control list. This
fix also grants read/write and execute permissions to the owner.
Signed-off-by: Salahuddin Khan <salah@docker.com>
In case ContainerExport() is called for an unmounted container, it leads
to a daemon panic as container.BaseFS, which is dereferenced here, is
nil.
To fix, do not rely on container.BaseFS; use the one returned from
rwlayer.Mount().
Fixes: 7a7357dae1 ("LCOW: Implemented support for docker cp + build")
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Instead of having to create a bunch of custom error types that are doing
nothing but wrapping another error in sub-packages, use a common helper
to create errors of the requested type.
e.g. instead of re-implementing this over and over:
```go
type notFoundError struct {
cause error
}
func(e notFoundError) Error() string {
return e.cause.Error()
}
func(e notFoundError) NotFound() {}
func(e notFoundError) Cause() error {
return e.cause
}
```
Packages can instead just do:
```
errdefs.NotFound(err)
```
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Signed-off-by: John Howard <jhoward@microsoft.com>
This PR has the API changes described in https://github.com/moby/moby/issues/34617.
Specifically, it adds an HTTP header "X-Requested-Platform" which is a JSON-encoded
OCI Image-spec `Platform` structure.
In addition, it renames (almost all) uses of a string variable platform (and associated)
methods/functions to os. This makes it much clearer to disambiguate with the swarm
"platform" which is really os/arch. This is a stepping stone to getting the daemon towards
fully multi-platform/arch-aware, and makes it clear when "operating system" is being
referred to rather than "platform" which is misleadingly used - sometimes in the swarm
meaning, but more often as just the operating system.
Take an extra reference to rwlayer while the container is being
committed or exported to avoid the removal of that layer.
Also add some checks before commit/export.
Signed-off-by: Yuanhong Peng <pengyuanhong@huawei.com>
This enables docker cp and ADD/COPY docker build support for LCOW.
Originally, the graphdriver.Get() interface returned a local path
to the container root filesystem. This does not work for LCOW, so
the Get() method now returns an interface that LCOW implements to
support copying to and from the container.
Signed-off-by: Akash Gupta <akagup@microsoft.com>
The `archive` package defines aliases for `io.ReadCloser` and
`io.Reader`. These don't seem to provide an benefit other than type
decoration. Per this change, several unnecessary type cases were
removed.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Moving all strings to the errors package wasn't a good idea after all.
Our custom implementation of Go errors predates everything that's nice
and good about working with errors in Go. Take as an example what we
have to do to get an error message:
```go
func GetErrorMessage(err error) string {
switch err.(type) {
case errcode.Error:
e, _ := err.(errcode.Error)
return e.Message
case errcode.ErrorCode:
ec, _ := err.(errcode.ErrorCode)
return ec.Message()
default:
return err.Error()
}
}
```
This goes against every good practice for Go development. The language already provides a simple, intuitive and standard way to get error messages, that is calling the `Error()` method from an error. Reinventing the error interface is a mistake.
Our custom implementation also makes very hard to reason about errors, another nice thing about Go. I found several (>10) error declarations that we don't use anywhere. This is a clear sign about how little we know about the errors we return. I also found several error usages where the number of arguments was different than the parameters declared in the error, another clear example of how difficult is to reason about errors.
Moreover, our custom implementation didn't really make easier for people to return custom HTTP status code depending on the errors. Again, it's hard to reason about when to set custom codes and how. Take an example what we have to do to extract the message and status code from an error before returning a response from the API:
```go
switch err.(type) {
case errcode.ErrorCode:
daError, _ := err.(errcode.ErrorCode)
statusCode = daError.Descriptor().HTTPStatusCode
errMsg = daError.Message()
case errcode.Error:
// For reference, if you're looking for a particular error
// then you can do something like :
// import ( derr "github.com/docker/docker/errors" )
// if daError.ErrorCode() == derr.ErrorCodeNoSuchContainer { ... }
daError, _ := err.(errcode.Error)
statusCode = daError.ErrorCode().Descriptor().HTTPStatusCode
errMsg = daError.Message
default:
// This part of will be removed once we've
// converted everything over to use the errcode package
// FIXME: this is brittle and should not be necessary.
// If we need to differentiate between different possible error types,
// we should create appropriate error types with clearly defined meaning
errStr := strings.ToLower(err.Error())
for keyword, status := range map[string]int{
"not found": http.StatusNotFound,
"no such": http.StatusNotFound,
"bad parameter": http.StatusBadRequest,
"conflict": http.StatusConflict,
"impossible": http.StatusNotAcceptable,
"wrong login/password": http.StatusUnauthorized,
"hasn't been activated": http.StatusForbidden,
} {
if strings.Contains(errStr, keyword) {
statusCode = status
break
}
}
}
```
You can notice two things in that code:
1. We have to explain how errors work, because our implementation goes against how easy to use Go errors are.
2. At no moment we arrived to remove that `switch` statement that was the original reason to use our custom implementation.
This change removes all our status errors from the errors package and puts them back in their specific contexts.
IT puts the messages back with their contexts. That way, we know right away when errors used and how to generate their messages.
It uses custom interfaces to reason about errors. Errors that need to response with a custom status code MUST implementent this simple interface:
```go
type errorWithStatus interface {
HTTPErrorStatusCode() int
}
```
This interface is very straightforward to implement. It also preserves Go errors real behavior, getting the message is as simple as using the `Error()` method.
I included helper functions to generate errors that use custom status code in `errors/errors.go`.
By doing this, we remove the hard dependency we have eeverywhere to our custom errors package. Yes, you can use it as a helper to generate error, but it's still very easy to generate errors without it.
Please, read this fantastic blog post about errors in Go: http://dave.cheney.net/2014/12/24/inspecting-errors
Signed-off-by: David Calavera <david.calavera@gmail.com>
So other packages don't need to import the daemon package when they
want to use this struct.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Signed-off-by: Tibor Vass <tibor@docker.com>
Side effects:
- Decouple daemon and container to start containers.
- Decouple daemon and container to copy files.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Although having a request ID available throughout the codebase is very
valuable, the impact of requiring a Context as an argument to every
function in the codepath of an API request, is too significant and was
not properly understood at the time of the review.
Furthermore, mixing API-layer code with non-API-layer code makes the
latter usable only by API-layer code (one that has a notion of Context).
This reverts commit de41640435, reversing
changes made to 7daeecd42d.
Signed-off-by: Tibor Vass <tibor@docker.com>
Conflicts:
api/server/container.go
builder/internals.go
daemon/container_unix.go
daemon/create.go
This PR adds a "request ID" to each event generated, the 'docker events'
stream now looks like this:
```
2015-09-10T15:02:50.000000000-07:00 [reqid: c01e3534ddca] de7c5d4ca927253cf4e978ee9c4545161e406e9b5a14617efb52c658b249174a: (from ubuntu) create
```
Note the `[reqID: c01e3534ddca]` part, that's new.
Each HTTP request will generate its own unique ID. So, if you do a
`docker build` you'll see a series of events all with the same reqID.
This allow for log processing tools to determine which events are all related
to the same http request.
I didn't propigate the context to all possible funcs in the daemon,
I decided to just do the ones that needed it in order to get the reqID
into the events. I'd like to have people review this direction first, and
if we're ok with it then I'll make sure we're consistent about when
we pass around the context - IOW, make sure that all funcs at the same level
have a context passed in even if they don't call the log funcs - this will
ensure we're consistent w/o passing it around for all calls unnecessarily.
ping @icecrime @calavera @crosbymichael
Signed-off-by: Doug Davis <dug@us.ibm.com>
- some method names were changed to have a 'Locking' suffix, as the
downcased versions already existed, and the existing functions simply
had locks around the already downcased version.
- deleting unused functions
- package comment
- magic numbers replaced by golang constants
- comments all over
Signed-off-by: Morgan Bauer <mbauer@us.ibm.com>
Move some calls to container.LogEvent down lower so that there's
less of a chance of them being missed. Also add a few more events
that appear to have been missed.
Added testcases for new events: commit, copy, resize, attach, rename, top
Signed-off-by: Doug Davis <dug@us.ibm.com>
