pull a container into a namespace

Pull an image provided as an argument to the program. We're only
interested in images for Linux/amd64 at the moment.

We setup a default namespace for containerd named `c2vm`. Images that
will be pulled by containerd will be stored inside that namespace.

Once the program is build it can be run like this:
```
; sudo ./c2vm -container docker.io/library/redis:latest
pulled docker.io/library/redis:latest (38667897 bytes)
```

And the image is indeed in the namespace:
```
; sudo ctr -n c2vm images ls -q
docker.io/library/redis:latest
```

1 files changed, 21 insertions, 0 deletions

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..f4d6398
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,21 @@
+module github.com/fcuny/containerd-to-vm
+
+go 1.16
+
+require (
+	github.com/Microsoft/go-winio v0.4.17 // indirect
+	github.com/Microsoft/hcsshim v0.8.16 // indirect
+	github.com/containerd/containerd v1.5.0-beta.4
+	github.com/containerd/continuity v0.0.0-20210315143101-93e15499afd5 // indirect
+	github.com/containerd/fifo v0.0.0-20210331061852-650e8a8a179d // indirect
+	github.com/containerd/typeurl v1.0.2 // indirect
+	github.com/gogo/googleapis v1.4.1 // indirect
+	github.com/google/go-cmp v0.5.5 // indirect
+	github.com/google/uuid v1.2.0 // indirect
+	github.com/opencontainers/image-spec v1.0.1
+	github.com/sirupsen/logrus v1.8.1 // indirect
+	golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1 // indirect
+	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
+	golang.org/x/sys v0.0.0-20210412220455-f1c623a9e750 // indirect
+	google.golang.org/grpc v1.37.0 // indirect
+)