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oci: introduce WithSpecFromFile combinator
We introduce a WithSpecFromFile option combinator to allow creation simpler creation of OCI specs from a file name. Often used as the first option in a `SpecOpts` slice, it simplifies choosing between a local file and the built-in default. The code in `ctr run` has been updated to use the new option, with out changing the order of operations or functionality present there. Signed-off-by: Stephen Day <[email protected]>
1 parent c8017d0 commit 2a1bd74

9 files changed

+162
-44
lines changed

‎cmd/ctr/commands/run/run.go

-13
Original file line numberDiff line numberDiff line change
@@ -19,9 +19,7 @@ package run
1919
import (
2020
gocontext "context"
2121
"encoding/csv"
22-
"encoding/json"
2322
"fmt"
24-
"io/ioutil"
2523
"strings"
2624

2725
"github.com/containerd/console"
@@ -37,17 +35,6 @@ import (
3735
"github.com/urfave/cli"
3836
)
3937

40-
func loadSpec(path string, s *specs.Spec) error {
41-
raw, err := ioutil.ReadFile(path)
42-
if err != nil {
43-
return errors.New("cannot load spec config file")
44-
}
45-
if err := json.Unmarshal(raw, s); err != nil {
46-
return errors.Errorf("decoding spec config file failed, current supported OCI runtime-spec : v%s", specs.Version)
47-
}
48-
return nil
49-
}
50-
5138
func withMounts(context *cli.Context) oci.SpecOpts {
5239
return func(ctx gocontext.Context, client oci.Client, container *containers.Container, s *specs.Spec) error {
5340
mounts := make([]specs.Mount, 0)

‎cmd/ctr/commands/run/run_unix.go

+11-9
Original file line numberDiff line numberDiff line change
@@ -52,6 +52,13 @@ func NewContainer(ctx gocontext.Context, client *containerd.Client, context *cli
5252
cOpts []containerd.NewContainerOpts
5353
spec containerd.NewContainerOpts
5454
)
55+
56+
if context.IsSet("config") {
57+
opts = append(opts, oci.WithSpecFromFile(context.String("config")))
58+
} else {
59+
opts = append(opts, oci.WithDefaultSpec())
60+
}
61+
5562
opts = append(opts, oci.WithEnv(context.StringSlice("env")))
5663
opts = append(opts, withMounts(context))
5764
cOpts = append(cOpts, containerd.WithContainerLabels(commands.LabelArgs(context.StringSlice("label"))))
@@ -117,15 +124,10 @@ func NewContainer(ctx gocontext.Context, client *containerd.Client, context *cli
117124
if context.IsSet("gpus") {
118125
opts = append(opts, nvidia.WithGPUs(nvidia.WithDevices(context.Int("gpus")), nvidia.WithAllCapabilities))
119126
}
120-
if context.IsSet("config") {
121-
var s specs.Spec
122-
if err := loadSpec(context.String("config"), &s); err != nil {
123-
return nil, err
124-
}
125-
spec = containerd.WithSpec(&s, opts...)
126-
} else {
127-
spec = containerd.WithNewSpec(opts...)
128-
}
127+
128+
var s specs.Spec
129+
spec = containerd.WithSpec(&s, opts...)
130+
129131
cOpts = append(cOpts, spec)
130132

131133
// oci.WithImageConfig (WithUsername, WithUserID) depends on rootfs snapshot for resolving /etc/passwd.

‎cmd/ctr/commands/run/run_windows.go

+9-9
Original file line numberDiff line numberDiff line change
@@ -63,6 +63,13 @@ func NewContainer(ctx gocontext.Context, client *containerd.Client, context *cli
6363
cOpts []containerd.NewContainerOpts
6464
spec containerd.NewContainerOpts
6565
)
66+
67+
if context.IsSet("config") {
68+
opts = append(opts, oci.WithSpecFromFile(context.String("config")))
69+
} else {
70+
opts = append(opts, oci.WithDefaultSpec())
71+
}
72+
6673
opts = append(opts, oci.WithImageConfig(image))
6774
opts = append(opts, oci.WithEnv(context.StringSlice("env")))
6875
opts = append(opts, withMounts(context))
@@ -74,15 +81,8 @@ func NewContainer(ctx gocontext.Context, client *containerd.Client, context *cli
7481
opts = append(opts, oci.WithProcessCwd(cwd))
7582
}
7683

77-
if context.IsSet("config") {
78-
var s specs.Spec
79-
if err := loadSpec(context.String("config"), &s); err != nil {
80-
return nil, err
81-
}
82-
spec = containerd.WithSpec(&s, opts...)
83-
} else {
84-
spec = containerd.WithNewSpec(opts...)
85-
}
84+
var s specs.Spec
85+
spec = containerd.WithSpec(&s, opts...)
8686

8787
cOpts = append(cOpts, containerd.WithContainerLabels(commands.LabelArgs(context.StringSlice("label"))))
8888
cOpts = append(cOpts, containerd.WithImage(image))

‎container_opts.go

+3-4
Original file line numberDiff line numberDiff line change
@@ -197,11 +197,10 @@ func WithNewSpec(opts ...oci.SpecOpts) NewContainerOpts {
197197
// WithSpec sets the provided spec on the container
198198
func WithSpec(s *oci.Spec, opts ...oci.SpecOpts) NewContainerOpts {
199199
return func(ctx context.Context, client *Client, c *containers.Container) error {
200-
for _, o := range opts {
201-
if err := o(ctx, client, c, s); err != nil {
202-
return err
203-
}
200+
if err := oci.ApplyOpts(ctx, client, c, s, opts...); err != nil {
201+
return err
204202
}
203+
205204
var err error
206205
c.Spec, err = typeurl.MarshalAny(s)
207206
return err

‎oci/spec.go

+15-2
Original file line numberDiff line numberDiff line change
@@ -34,10 +34,23 @@ func GenerateSpec(ctx context.Context, client Client, c *containers.Container, o
3434
if err != nil {
3535
return nil, err
3636
}
37+
38+
return s, ApplyOpts(ctx, client, c, s, opts...)
39+
}
40+
41+
// ApplyOpts applys the options to the given spec, injecting data from the
42+
// context, client and container instance.
43+
func ApplyOpts(ctx context.Context, client Client, c *containers.Container, s *Spec, opts ...SpecOpts) error {
3744
for _, o := range opts {
3845
if err := o(ctx, client, c, s); err != nil {
39-
return nil, err
46+
return err
4047
}
4148
}
42-
return s, nil
49+
50+
return nil
51+
}
52+
53+
func createDefaultSpec(ctx context.Context, id string) (*Spec, error) {
54+
var s Spec
55+
return &s, populateDefaultSpec(ctx, &s, id)
4356
}

‎oci/spec_opts.go

+35
Original file line numberDiff line numberDiff line change
@@ -18,10 +18,13 @@ package oci
1818

1919
import (
2020
"context"
21+
"encoding/json"
22+
"io/ioutil"
2123
"strings"
2224

2325
"github.com/containerd/containerd/containers"
2426
specs "github.com/opencontainers/runtime-spec/specs-go"
27+
"github.com/pkg/errors"
2528
)
2629

2730
// SpecOpts sets spec specific information to a newly generated OCI spec
@@ -46,6 +49,38 @@ func setProcess(s *Spec) {
4649
}
4750
}
4851

52+
// WithDefaultSpec returns a SpecOpts that will populate the spec with default
53+
// values.
54+
//
55+
// Use as the first option to clear the spec, then apply options afterwards.
56+
func WithDefaultSpec() SpecOpts {
57+
return func(ctx context.Context, _ Client, c *containers.Container, s *Spec) error {
58+
return populateDefaultSpec(ctx, s, c.ID)
59+
}
60+
}
61+
62+
// WithSpecFromBytes loads the the spec from the provided byte slice.
63+
func WithSpecFromBytes(p []byte) SpecOpts {
64+
return func(_ context.Context, _ Client, _ *containers.Container, s *Spec) error {
65+
*s = Spec{} // make sure spec is cleared.
66+
if err := json.Unmarshal(p, s); err != nil {
67+
return errors.Wrapf(err, "decoding spec config file failed, current supported OCI runtime-spec : v%s", specs.Version)
68+
}
69+
return nil
70+
}
71+
}
72+
73+
// WithSpecFromFile loads the specification from the provided filename.
74+
func WithSpecFromFile(filename string) SpecOpts {
75+
return func(ctx context.Context, c Client, container *containers.Container, s *Spec) error {
76+
p, err := ioutil.ReadFile(filename)
77+
if err != nil {
78+
return errors.Wrap(err, "cannot load spec config file")
79+
}
80+
return WithSpecFromBytes(p)(ctx, c, container, s)
81+
}
82+
}
83+
4984
// WithProcessArgs replaces the args on the generated spec
5085
func WithProcessArgs(args ...string) SpecOpts {
5186
return func(_ context.Context, _ Client, _ *containers.Container, s *Spec) error {

‎oci/spec_opts_test.go

+80
Original file line numberDiff line numberDiff line change
@@ -17,8 +17,16 @@
1717
package oci
1818

1919
import (
20+
"context"
21+
"encoding/json"
22+
"io/ioutil"
23+
"log"
24+
"os"
25+
"reflect"
2026
"testing"
2127

28+
"github.com/containerd/containerd/containers"
29+
"github.com/containerd/containerd/namespaces"
2230
specs "github.com/opencontainers/runtime-spec/specs-go"
2331
)
2432

@@ -87,3 +95,75 @@ func TestWithMounts(t *testing.T) {
8795
t.Fatal("invaid mount")
8896
}
8997
}
98+
99+
func TestWithDefaultSpec(t *testing.T) {
100+
t.Parallel()
101+
var (
102+
s Spec
103+
c = containers.Container{ID: "TestWithDefaultSpec"}
104+
ctx = namespaces.WithNamespace(context.Background(), "test")
105+
)
106+
107+
if err := ApplyOpts(ctx, nil, &c, &s, WithDefaultSpec()); err != nil {
108+
t.Fatal(err)
109+
}
110+
111+
expected, err := createDefaultSpec(ctx, c.ID)
112+
if err != nil {
113+
t.Fatal(err)
114+
}
115+
116+
if reflect.DeepEqual(s, Spec{}) {
117+
t.Fatalf("spec should not be empty")
118+
}
119+
120+
if !reflect.DeepEqual(&s, expected) {
121+
t.Fatalf("spec from option differs from default: \n%#v != \n%#v", &s, expected)
122+
}
123+
}
124+
125+
func TestWithSpecFromFile(t *testing.T) {
126+
t.Parallel()
127+
var (
128+
s Spec
129+
c = containers.Container{ID: "TestWithDefaultSpec"}
130+
ctx = namespaces.WithNamespace(context.Background(), "test")
131+
)
132+
133+
fp, err := ioutil.TempFile("", "testwithdefaultspec.json")
134+
if err != nil {
135+
t.Fatal(err)
136+
}
137+
defer fp.Close()
138+
defer func() {
139+
if err := os.Remove(fp.Name()); err != nil {
140+
log.Printf("failed to remove tempfile %v: %v", fp.Name(), err)
141+
}
142+
}()
143+
144+
expected, err := GenerateSpec(ctx, nil, &c)
145+
if err != nil {
146+
t.Fatal(err)
147+
}
148+
149+
p, err := json.Marshal(expected)
150+
if err != nil {
151+
t.Fatal(err)
152+
}
153+
154+
if _, err := fp.Write(p); err != nil {
155+
t.Fatal(err)
156+
}
157+
158+
if err := ApplyOpts(ctx, nil, &c, &s, WithSpecFromFile(fp.Name())); err != nil {
159+
t.Fatal(err)
160+
}
161+
162+
if reflect.DeepEqual(s, Spec{}) {
163+
t.Fatalf("spec should not be empty")
164+
}
165+
166+
if !reflect.DeepEqual(&s, expected) {
167+
t.Fatalf("spec from option differs from default: \n%#v != \n%#v", &s, expected)
168+
}
169+
}

‎oci/spec_unix.go

+5-4
Original file line numberDiff line numberDiff line change
@@ -76,12 +76,13 @@ func defaultNamespaces() []specs.LinuxNamespace {
7676
}
7777
}
7878

79-
func createDefaultSpec(ctx context.Context, id string) (*Spec, error) {
79+
func populateDefaultSpec(ctx context.Context, s *Spec, id string) error {
8080
ns, err := namespaces.NamespaceRequired(ctx)
8181
if err != nil {
82-
return nil, err
82+
return err
8383
}
84-
s := &Spec{
84+
85+
*s = Spec{
8586
Version: specs.Version,
8687
Root: &specs.Root{
8788
Path: defaultRootfsPath,
@@ -183,5 +184,5 @@ func createDefaultSpec(ctx context.Context, id string) (*Spec, error) {
183184
Namespaces: defaultNamespaces(),
184185
},
185186
}
186-
return s, nil
187+
return nil
187188
}

‎oci/spec_windows.go

+4-3
Original file line numberDiff line numberDiff line change
@@ -22,8 +22,8 @@ import (
2222
specs "github.com/opencontainers/runtime-spec/specs-go"
2323
)
2424

25-
func createDefaultSpec(ctx context.Context, id string) (*Spec, error) {
26-
return &Spec{
25+
func populateDefaultSpec(ctx context.Context, s *Spec, id string) error {
26+
*s = Spec{
2727
Version: specs.Version,
2828
Root: &specs.Root{},
2929
Process: &specs.Process{
@@ -39,5 +39,6 @@ func createDefaultSpec(ctx context.Context, id string) (*Spec, error) {
3939
AllowUnqualifiedDNSQuery: true,
4040
},
4141
},
42-
}, nil
42+
}
43+
return nil
4344
}

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