The top-level `docker deploy` command (using the "Docker Application Bundle"
(`.dab`) file format was introduced as an experimental feature in Docker 1.13 /
17.03, but superseded by support for Docker Compose files.
With no development being done on this feature, and no active use of the file
format, support for the DAB file format and the top-level `docker deploy` command
(hidden by default in 19.03), is removed in this patch, in favour of `docker stack deploy`
using compose files.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Signed-off-by: Anca Iordache <anca.iordache@docker.com>
Possible approach for client info
- split ClientInfo() into ClientInfo() and loadClientInfo()
- split ConfigFile() into ConfigFile() and loadConfigFile()
- ConfigFile() and ClientInfo() call their corresponding loadXX function
if it has not yet been loaded; this allows them to be used before
Initialize() was called.
- Initialize() *always* (re-)loads the configuration; this makes sure
that the correct configuration is used when actually calling commands.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/stack/kubernetes/convert_test.go:199:35: Using the variable on range scope `c` in function literal (scopelint)
conv, err := NewStackConverter(c.version)
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/container/create_test.go:120:20: Using the variable on range scope `c` in function literal (scopelint)
defer func() { c.ResponseCounter++ }()
^
cli/command/container/create_test.go:121:12: Using the variable on range scope `c` in function literal (scopelint)
switch c.ResponseCounter {
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/stack/kubernetes/watcher_test.go:44:20: Using a reference for the variable on range scope `obj` (scopelint)
if err := o.Add(&obj); err != nil {
^
cli/command/stack/kubernetes/watcher_test.go:49:20: Using a reference for the variable on range scope `obj` (scopelint)
if err := o.Add(&obj); err != nil {
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/cli_test.go:157:15: Using the variable on range scope `testcase` in function literal (scopelint)
pingFunc: testcase.pingFunc,
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/trust/key_load_test.go:121:27: Using the variable on range scope `keyID` in function literal (scopelint)
testLoadKeyFromPath(t, keyID, keyBytes)
^
cli/command/trust/key_load_test.go:176:32: Using the variable on range scope `keyBytes` in function literal (scopelint)
testLoadKeyTooPermissive(t, keyBytes)
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/context/create_test.go:270:31: Using the variable on range scope `c` in function literal (scopelint)
Name: c.name,
^
cli/command/context/create_test.go:271:31: Using the variable on range scope `c` in function literal (scopelint)
Description: c.description,
^
cli/command/context/create_test.go:272:31: Using the variable on range scope `c` in function literal (scopelint)
DefaultStackOrchestrator: c.orchestrator,
cli/command/context/create_test.go:346:31: Using the variable on range scope `c` in function literal (scopelint)
Name: c.name,
^
cli/command/context/create_test.go:347:31: Using the variable on range scope `c` in function literal (scopelint)
Description: c.description,
^
cli/command/context/create_test.go:348:31: Using the variable on range scope `c` in function literal (scopelint)
DefaultStackOrchestrator: c.orchestrator,
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/formatter/container_test.go:315:17: Error return value of `ContainerWrite` is not checked (errcheck)
ContainerWrite(context.context, containers)
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/cli_test.go:297:11: Error return value of `cli.Apply` is not checked (errcheck)
cli.Apply(
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
cli/command/image/build.go:434:32: SA1006: printf-style function with dynamic format string and no further arguments should use print-style function instead (staticcheck)
fmt.Fprintf(dockerCli.Out(), imageID)
^
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/utils.go:81:20: SA1006: printf-style function with dynamic format string and no further arguments should use print-style function instead (staticcheck)
fmt.Fprintf(outs, message)
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/trust/key_generate.go:91:30: SA1006: printf-style function with dynamic format string and no further arguments should use print-style function instead (staticcheck)
fmt.Fprintf(streams.Out(), err.Error())
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/service/update_test.go:31:16: SA1012: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (staticcheck)
updateService(nil, nil, flags, spec)
^
cli/command/service/update_test.go:535:16: SA1012: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (staticcheck)
updateService(nil, nil, flags, spec)
^
cli/command/service/update_test.go:540:16: SA1012: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (staticcheck)
updateService(nil, nil, flags, spec)
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Running `docker stack services <STACK> --orchestrator swarm would yield
the message "Noting found in stack: asdf" with an exit code 0. The same
command with kubernetes orchestrator would yield "nothing found in
stack: adsf" (note the lower-case "nothing") and a non-zero exit code.
This change makes the `stack services` command uniform for both
orchestrators. The logic of getting and printing services is split to
reuse the same formatting code.
Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
API v1.41 adds a new option to get the number of desired
and running tasks when listing services. This patch enables
this functionality, and provides a fallback mechanism when
the ServiceStatus is not available, which would be when
using an older API version.
Now that the swarm.Service struct captures this information,
the `ListInfo` type is no longer needed, so it is removed,
and the related list- and formatting functions have been
modified accordingly.
To reduce repetition, sorting the services has been moved
to the formatter. This is a slight change in behavior, but
all calls to the formatter performed this sort first, so
the change will not lead to user-facing changes.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This patch:
- Adds new GlobalService and ServiceStatus options
- Makes the NodeList() function functional
- Minor improvment to the `newService()` function to allow passing options
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/container/opts.go:700:37: Using a reference for the variable on range scope `n` (scopelint)
if err := applyContainerOptions(&n, copts); err != nil {
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
```
cli/command/service/update.go:1007:43: Using a reference for the variable on range scope `entry` (scopelint)
if _, ok := portSet[portConfigToString(&entry)]; !ok {
^
cli/command/service/update.go:1008:32: Using a reference for the variable on range scope `entry` (scopelint)
portSet[portConfigToString(&entry)] = entry
^
cli/command/service/update.go:1034:44: Using a reference for the variable on range scope `port` (scopelint)
if _, ok := portSet[portConfigToString(&port)]; ok {
^
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This case was in a test in the engine repository, where
it is being removed, so add it to the list of existing
tests here.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Before this patch:
```
Usage: docker build [OPTIONS] PATH | URL | -
Build an image from a Dockerfile
Options:
--add-host list Add a custom host-to-IP mapping (host:ip)
--build-arg list Set build-time variables
--cache-from strings Images to consider as cache sources
--cgroup-parent string Optional parent cgroup for the container
--cpu-period int Limit the CPU CFS (Completely Fair Scheduler) period
--cpu-quota int Limit the CPU CFS (Completely Fair Scheduler) quota
-c, --cpu-shares int CPU shares (relative weight)
--cpuset-cpus string CPUs in which to allow execution (0-3, 0,1)
--cpuset-mems string MEMs in which to allow execution (0-3, 0,1)
--disable-content-trust Skip image verification (default true)
-f, --file string Name of the Dockerfile (Default is 'PATH/Dockerfile')
--force-rm Always remove intermediate containers
--iidfile string Write the image ID to the file
--isolation string Container isolation technology
--label list Set metadata for an image
-m, --memory bytes Memory limit
--memory-swap bytes Swap limit equal to memory plus swap: '-1' to enable unlimited swap
--network string Set the networking mode for the RUN instructions during build (default "default")
--no-cache Do not use cache when building the image
-o, --output stringArray Output destination (format: type=local,dest=path)
--platform string Set platform if server is multi-platform capable
--progress string Set type of progress output (auto, plain, tty). Use plain to show container output (default "auto")
--pull Always attempt to pull a newer version of the image
-q, --quiet Suppress the build output and print image ID on success
--rm Remove intermediate containers after a successful build (default true)
--secret stringArray Secret file to expose to the build (only if BuildKit enabled): id=mysecret,src=/local/secret
--security-opt strings Security options
--shm-size bytes Size of /dev/shm
--squash Squash newly built layers into a single new layer
--ssh stringArray SSH agent socket or keys to expose to the build (only if BuildKit enabled) (format: default|<id>[=<socket>|<key>[,<key>]])
-t, --tag list Name and optionally a tag in the 'name:tag' format
--target string Set the target build stage to build.
--ulimit ulimit Ulimit options (default [])
```
With this patch applied:
```
DOCKER_BUILDKIT=1 docker build --help
Usage: docker build [OPTIONS] PATH | URL | -
Build an image from a Dockerfile
Options:
--add-host list Add a custom host-to-IP mapping (host:ip)
--build-arg list Set build-time variables
--cache-from strings Images to consider as cache sources
--disable-content-trust Skip image verification (default true)
-f, --file string Name of the Dockerfile (Default is 'PATH/Dockerfile')
--iidfile string Write the image ID to the file
--isolation string Container isolation technology
--label list Set metadata for an image
--network string Set the networking mode for the RUN instructions during build (default "default")
--no-cache Do not use cache when building the image
-o, --output stringArray Output destination (format: type=local,dest=path)
--platform string Set platform if server is multi-platform capable
--progress string Set type of progress output (auto, plain, tty). Use plain to show container output (default "auto")
--pull Always attempt to pull a newer version of the image
-q, --quiet Suppress the build output and print image ID on success
--secret stringArray Secret file to expose to the build (only if BuildKit enabled): id=mysecret,src=/local/secret
--squash Squash newly built layers into a single new layer
--ssh stringArray SSH agent socket or keys to expose to the build (only if BuildKit enabled) (format: default|<id>[=<socket>|<key>[,<key>]])
-t, --tag list Name and optionally a tag in the 'name:tag' format
--target string Set the target build stage to build.
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
--stream was always experimental and this patch removes the functionality.
Users should enable BuildKit with DOCKER_BUILDKIT=1
Signed-off-by: Tibor Vass <tibor@docker.com>
The State field allows printing the container state without
additional information about uptime, healthcheck, etc.
With this patch, the container's state can be printed independently:
```bash
docker ps -a --format '{{.State}}'
running
paused
exited
created
```
```bash
docker ps -a --format 'table {{.Names}}\t{{.State}}\t{{.Status}}'
NAMES STATE STATUS
elastic_burnell running Up About a minute
pausie paused Up 5 minutes (Paused)
peaceful_stonebraker exited Exited (0) 10 hours ago
vigilant_shaw created Created
```
```bash
docker ps -a --format 'raw'
container_id: 0445f73f3a71
image: docker-cli-dev
command: "ash"
created_at: 2019-07-12 11:16:11 +0000 UTC
state: running
status: Up 2 minutes
names: elastic_burnell
labels:
ports:
container_id: 1aff69a3912c
image: nginx:alpine
command: "nginx -g 'daemon of ..."
created_at: 2019-07-12 11:12:10 +0000 UTC
state: paused
status: Up 6 minutes (Paused)
names: pausie
labels: maintainer=NGINX Docker Maintainers <docker-maint@nginx.com>
ports: 80/tcp
container_id: d48acf66c318
image: alpine:3.9.3
command: "id -u"
created_at: 2019-07-12 00:52:17 +0000 UTC
state: exited
status: Exited (0) 10 hours ago
names: peaceful_stonebraker
labels:
ports:
container_id: a0733fe0dace
image: b7b28af77ffe
command: "/bin/sh -c '#(nop) ..."
created_at: 2019-07-12 00:51:29 +0000 UTC
state: created
status: Created
names: vigilant_shaw
labels:
ports:
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This partially reverts e0b59ab52b,
and does not automatically disable proxying signals in TTY-mode
Before this change:
------------------------------------
Start a container with a TTY in one shell:
```
docker run -it --init --name repro-28872 busybox sleep 30
```
then, in another shell, kill the docker cli:
```
kill `pgrep -f repro-28872`
```
Notice that the CLI was killed, but the signal not forwarded to the container;
the container continues running
```
docker container inspect --format '{{ .State.Status }}' repro-28872
running
docker container rm -f repro-28872
```
After this change:
------------------------------------
Start a container with a TTY in one shell:
```
docker run -it --init --name repro-28872 busybox sleep 30
```
then, in another shell, kill the docker cli:
```
kill `pgrep -f repro-28872`
```
Verify that the signal was forwarded to the container, and the container exited
```
docker container inspect --format '{{ .State.Status }}' repro-28872
exited
docker container rm -f repro-28872
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This code was attempting to check Linux file permissions
to determine if the key was accessible by other users, which
doesn't work, and therefore prevented users on Windows
to load keys.
Skipping this check on Windows (correspinding tests
were already skipped).
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
For backward compatibility: if no custom options are provided for the network,
and only a single network is specified, omit the endpoint-configuration
on the client (the daemon will still create it when creating the container)
This fixes an issue on older versions of legacy Swarm, which did not support
`NetworkingConfig.EndpointConfig`.
This was introduced in 5bc09639cc (#1767)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Adds capabilities to import a .zip file with importZip.
Detects the content type of source by checking bytes & DetectContentType.
Adds LimitedReader reader, a fork of io.LimitedReader,
was needed for better error messaging instead of just getting back EOF.
We are using limited reader to avoid very big files causing memory issues.
Adds a new file size limit for context imports,
this limit is used for the main file for .zip & .tar and individual compressed
files for .zip.
Added TestImportZip that will check the import content type
Then will assert no err on Importing .zip file
Signed-off-by: Goksu Toprak <goksu.toprak@docker.com>
This is less of a layering violation and removes some ugly hardcoded
`"kubernetes"` strings which were needed to avoid an import loop.
Signed-off-by: Ian Campbell <ijc@docker.com>
This removes the need for the core context code to import
`github.com/docker/cli/cli/context/kubernetes` which in turn reduces the
transitive import tree in this file to not pull in all of Kubernetes.
Note that this means that any calling code which is interested in the
kubernetes endpoint must import `github.com/docker/cli/cli/context/kubernetes`
itself somewhere in order to trigger the dynamic registration. In practice
anything which is interested in Kubernetes must import that package (e.g.
`./cli/command/context.list` does for the `EndpointFromContext` function) to do
anything useful, so this restriction is not too onerous.
As a special case a small amount of Kubernetes related logic remains in
`ResolveDefaultContext` to handle error handling when the stack orchestrator
includes Kubernetes. In order to avoid a circular import loop this hardcodes
the kube endpoint name.
Similarly to avoid an import loop the existing `TestDefaultContextInitializer`
cannot continue to unit test for the Kubernetes case, so that aspect of the
test is carved off into a very similar test in the kubernetes context package.
Lastly, note that the kubernetes endpoint is now modifiable via
`WithContextEndpointType`.
Signed-off-by: Ian Campbell <ijc@docker.com>
These are needed by any dynamically registered (via
`RegisterDefaultStoreEndpoints`) endpoint type to write a useful/sensible unit
test.
Signed-off-by: Ian Campbell <ijc@docker.com>
Previously an endpoint registered using `RegisterDefaultStoreEndpoints` would
not be taken into consideration by `resolveDefaultContext` and so could not
provide any details.
Resolve this by passing a `store.Config` to `resolveDefaultContext` and using
it to iterate over all registered endpoints. Any endpoint can ensure that their
type implements the new `EndpointDefaultResolver` in order to provide a default.
The Docker and Kubernetes endpoints are special cased, shortly the Kubernetes
one will be refactored to be dynamically registered.
Signed-off-by: Ian Campbell <ijc@docker.com>
The comment on `github.com/docker/cli/kubernetes.NewKubernetesConfig` said:
// Deprecated: Use github.com/docker/compose-on-kubernetes/api.NewKubernetesConfig instead
By making this switch in `github.com/docker/cli/context/kubernetes/load.go` we
break a vendoring chain:
`github.com/docker/cli/cli/command`
→ `vendor/github.com/docker/cli/cli/context/kubernetes/load.go`
→ `vendor/github.com/docker/cli/kubernetes`
→ `github.com/docker/compose-on-kubernetes/api/compose/...`
This means that projects which just want `github.com/docker/cli/cli/command`
(which is itself pulled in transitively by
`github.com/docker/cli/cli-plugins/plugin`) which do not themselves need the
compose-on-kubernetes API avoid a huge pile of transitive dependencies.
On one of my private projects the diff on the vendor dir is:
280 files changed, 21 insertions(+), 211346 deletions(-)
and includes dropping:
* `github.com/docker/compose-on-kubernetes/api/compose/{clone,impersonation}`
* `github.com/docker/compose-on-kubernetes/api/compose/{v1alpha3,v1beta1,v1beta2,v1beta3}`
* `github.com/google/btree`
* `github.com/googleapis/gnostic`
* `github.com/gregjones/httpcache`
* `github.com/peterbourgon/diskv`
* `k8s.io/api/*` (_lots_ of subpackages)
* `k8s.io/client-go/{discovery,kubernetes/scheme}`
and I've gone from:
$ du -sh vendor/k8s.io/
8.1M vendor/k8s.io/
to:
$ du -sh vendor/k8s.io/
2.1M vendor/k8s.io/
(overall I went from 36M → 29M of vendor dir for this particular project)
The change to `cli/command/system/version.go` is just for consistency and
allows us to drop the now unused alias.
Signed-off-by: Ian Campbell <ijc@docker.com>
Refactor `RunCreate` slightly so that all three paths always produce the same
output, namely the name of the new context of `stdout` (for scripting) and the
success log message on `stderr`.
Validate by extending the existing unit tests to always check the output is as
expected.
Signed-off-by: Ian Campbell <ijc@docker.com>
- Follows the proposal on issue [#34394](https://github.com/moby/moby/issues/34394)
- Maintains current behavior as default (Pull image if missing)
- Adds tristate flag allowing modification (PullMissing, PullAlways, PullNever)
Signed-off-by: Zander Mackie <zmackie@gmail.com>
With this patch it is possible to alias an existing allowed command.
At the moment only builder allows an alias.
This also properly puts the build command under builder, instead of image
where it was for historical reasons.
Signed-off-by: Tibor Vass <tibor@docker.com>
This is to make it easier to implement support for exporting contexts in
3rd party code, or to create mocks in tests.
2 exemples where it simplify things:
- docker-app desktop-specific context decorator (which rewrites parts of
the docker context to simplify UX when using on Docker Desktop contexts)
- ucp for including a context in the connection bundle
Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>
This change refines the warning message returned during docker login to
only warn for unencrypted storage when the users password is being stored.
If the remote registry supports identity tokens, omit the warning,
since those tokens can be independently managed and revoked.
Signed-off-by: Daniel Hiltgen <daniel.hiltgen@docker.com>
The github.com/flynn-archive/go-shlex package is a fork of Google/shlex,
and the repository is now archived, so let's switch to the maintained
version.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Adds tests for setting and updating swarm service CredentialSpecs,
especially when using a Config as a credential spec.
Signed-off-by: Drew Erny <drew.erny@docker.com>
Updates the CredentialSpec handling code for services to allow using
swarm Configs.
Additionally, fixes a bug where the `--credential-spec` flag would not
be respected on service updates.
Signed-off-by: Drew Erny <drew.erny@docker.com>
This regroup all Kubernetes extra fields for compose-on-kubernetes
v1alpha3 in a single x-kubernetes object.
Also use the same naming scheme as cap_add etc. for fiels inside this
object.
Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>
On the server v0.4.21 has introduced a better way of dealing with
intra-stack networking: if the user can specify a list of endpoints
exposed internally, we now can setup a ClusterIP for this to avoid the
pitfalls of DNS-based load balancing.
This exposes the feature using the "Expose" compose field, and adds an
extra x-internal-service-type field to explicitly define how intra-stack
networking is handled on a service.
Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>
For clarity, on `docker context use` or `docker context ls`, this adds a
warning if the DOCKER_HOST variable is set because it overrides the
active context.
Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>
This allows setting the ip/ipv6 address as an option in the
advanced `--network` syntax;
```
docker run --network name=mynetwork,ip=172.20.88.22,ip6=2001:db8::8822
```
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This refactors the way networking options are parsed, and makes the
client able to pass options for multiple networks. Currently, the
daemon does not yet accept multiple networks when creating a container,
and will produce an error.
For backward-compatibility, the following global networking-related
options are associated with the first network (in case multiple
networks are set);
- `--ip`
- `--ip6`
- `--link`
- `--link-local-ip`
- `--network-alias`
Not all of these options are supported yet in the advanced notation,
but for options that are supported, setting both the per-network option
and the global option will produce a "conflicting options" error.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
The commit contains cli changes to support driver options for a network in
docker run and docker network connect cli's. The driver-opt, aliases is now
supported in the form of csv as per network option in service commands in
swarm mode since docker/cli#62 . This commit extends this support to docker
run command as well.
For docker connect command `--driver-opt` is added to pass driver specific
options for the network the container is connecting to.
Signed-off-by: Abhinandan Prativadi <abhi@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
--from creates a context from a named context.
By default `context create` will create a context from the current context.
Replaced "from-current=" docker/kubernetes option with "from=" to allow specifying which context to copy the settings from.
Signed-off-by: Nick Adcock <nick.adcock@docker.com>
Old selector was wrong (it watched for the label we applied to child
resources when reconciling the stack, instead of the stack itself)
This should be back-ported to older version of the CLI
Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>
bump required:
- replacing vendor ghodss/yaml with sigs.k8s.io/yaml
- adding vendor k8s.io/klog and github.com/evanphx
- compose-on-kubernetes
removed 'IncludeUninitialized' from watch as it have been removed from k8s
Signed-off-by: Nick Adcock <nick.adcock@docker.com>
Instead of using an `if else if else`, switch to a sequence of independent
`if` blocks containing a `return`.
Instead of defining a return variable and updating it in the `if` blocks
and returning at the end, make each `if` block return the desired value
independenly.
Signed-off-by: David Scott <dave.scott@docker.com>
Previously if the Docker engine was not running the behaviour of
commands would vary depending on whether the --debug flag was provided.
For example, consider `docker logout`:
$ docker logout
Not logged in to
-- note the missing server URL
$ docker --debug logout
Warning: failed to get default registry endpoint from daemon (Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?). Using system default: https://index.docker.io/v1/
Not logged in to https://index.docker.io/v1/
-- note the server URL is present
This patch makes only the debug printing conditional on the `--debug` flag,
not the return value.
Signed-off-by: David Scott <dave.scott@docker.com>
As pointed out in #1459, docker cli fails to detect that the input is a tarball,
in case it is generated by `git archive --format=tgz`.
This happens because `git archive` adds some metadata to the initial tar header,
and so it is more than 1 block (of 512 bytes) long, while we only provide 1 block
to archive/tar.Next() and it fails.
To fix, give it 2 blocks :)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>