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Amit Kumar Das
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feat(command): initial code for Command controller (#96)
This is the first commit to realise Command controller. Command is a new custom resource that lets users to run one or more os commands or a complete shell script from within a container. In addition this Command resource has the ability to grab the output after running these commands and update the results in its status field. Applying a Command resource will result in either of following Kubernetes resources: - Job // a native resource - DaemonJob // a custom resource refer - #1 Signed-off-by: AmitKumarDas <[email protected]>
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‎Makefile

+2-1
Original file line numberDiff line numberDiff line change
@@ -2,8 +2,8 @@ PWD := ${CURDIR}
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OS = $(shell uname)
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5-
GIT_TAGS = $(shell git fetch --all --tags)
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PACKAGE_VERSION ?= $(shell git describe --always --tags)
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GIT_TAGS = $(shell git fetch --all --tags)
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ALL_SRC = $(shell find . -name "*.go" | grep -v -e "vendor")
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# We are using docker hub as the default registry
@@ -45,6 +45,7 @@ testv:
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image: $(GIT_TAGS)
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docker build -t $(IMG_REPO):$(PACKAGE_VERSION) .
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.PHONY: push
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push: image
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docker push $(IMG_REPO):$(PACKAGE_VERSION)

‎README.md

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Original file line numberDiff line numberDiff line change
@@ -9,4 +9,12 @@ It is important to understand that these declarative patterns are built upon pro
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### When to use d-operators
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D-operators is not meant to build complex controllers like Deployment, StatefulSet or Pod in a declarative yaml. However, if one needs to use Deployment, StatefulSet, Pod, etc. to build new k8s controller(s) then d-operators' declarative constructs _(read custom resources)_ should be considered to build one.
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However, any controller which is complex and at the same time is **generic** enough to be used along with other kubernetes resources, can be implemented as a core d-operator custom resource.
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However, any controller which is complex and at the same time is **generic** enough to be used along with other kubernetes resources, can be implemented as a core d-operator custom resource.
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### Available controllers
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- [x] kind: Recipe
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- [ ] kind: HTTP
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- [ ] kind: Chef
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- [ ] kind: Command
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- [ ] kind: DaemonJob
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- [ ] kind: MasterChef

‎cmd/commander/main.go

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@@ -0,0 +1,250 @@
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/*
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Copyright 2020 The MayaData Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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https://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package main
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import (
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"flag"
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"os"
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"path/filepath"
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v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/client-go/dynamic"
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"k8s.io/client-go/rest"
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"k8s.io/client-go/tools/clientcmd"
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"k8s.io/client-go/util/homedir"
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"k8s.io/client-go/util/retry"
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"k8s.io/klog/v2"
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"mayadata.io/d-operators/common/unstruct"
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"mayadata.io/d-operators/pkg/command"
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types "mayadata.io/d-operators/types/command"
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)
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var (
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commandKind = flag.String(
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"command-kind",
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"Command",
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"Kind of Command custom resource",
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)
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commandResource = flag.String(
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"command-resource",
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"commands",
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"Resource name of Command custom resource",
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)
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commandGroup = flag.String(
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"command-group",
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"dope.metacontroller.io",
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"Group of Command custom resource",
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)
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commandVersion = flag.String(
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"command-version",
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"v1",
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"Version of Command custom resource",
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)
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commandName = flag.String(
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"command-name",
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"",
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"Name of Command custom resource",
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)
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commandNamespace = flag.String(
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"command-ns",
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"",
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"Namespace of Command custom resource",
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)
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kubeAPIServerURL = flag.String(
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"kube-apiserver-url",
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"",
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`Kubernetes api server url (same format as used by kubectl).
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If not specified, uses in-cluster config`,
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)
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kubeconfig *string
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clientGoQPS = flag.Float64(
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"client-go-qps",
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5,
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"Number of queries per second client-go is allowed to make (default 5)",
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)
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clientGoBurst = flag.Int(
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"client-go-burst",
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10,
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"Allowed burst queries for client-go (default 10)",
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)
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)
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// main function is the entry point of this binary.
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//
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// This binary is meant to be run to completion. In other
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// words this does not expose any long running service.
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//
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// NOTE:
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// A kubernetes **Job** can make use of this binary
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func main() {
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if home := homedir.HomeDir(); home != "" {
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kubeconfig = flag.String(
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"kubeconfig",
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filepath.Join(home, ".kube", "config"),
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"(optional) absolute path to the kubeconfig file",
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)
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} else {
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kubeconfig = flag.String(
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"kubeconfig",
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"",
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"absolute path to the kubeconfig file",
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)
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}
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113+
flag.Set("alsologtostderr", "true")
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flag.Parse()
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klogFlags := flag.NewFlagSet("klog", flag.ExitOnError)
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klog.InitFlags(klogFlags)
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// Sync the glog and klog flags.
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flag.CommandLine.VisitAll(func(f1 *flag.Flag) {
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f2 := klogFlags.Lookup(f1.Name)
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if f2 != nil {
123+
value := f1.Value.String()
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f2.Value.Set(value)
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}
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})
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defer klog.Flush()
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if *commandName == "" {
130+
klog.Fatal("Invalid arguments: Flag 'command-name' must be set")
131+
}
132+
133+
klog.V(1).Infof("Command custom resource: kind %s", *commandKind)
134+
klog.V(1).Infof("Command custom resource: resource %s", *commandResource)
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klog.V(1).Infof("Command custom resource: group %s", *commandGroup)
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klog.V(1).Infof("Command custom resource: version %s", *commandVersion)
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klog.V(1).Infof("Command custom resource: name %s", *commandName)
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klog.V(1).Infof("Command custom resource: namespace %s", *commandNamespace)
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runCommand(getRestConfig())
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os.Exit(0)
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}
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func getRestConfig() *rest.Config {
145+
var config *rest.Config
146+
var err error
147+
if *kubeconfig != "" {
148+
klog.V(1).Infof("Using kubeconfig %s", *kubeconfig)
149+
config, err = clientcmd.BuildConfigFromFlags("", *kubeconfig)
150+
} else if *kubeAPIServerURL != "" {
151+
klog.V(1).Infof("Using kubernetes api server url %s", *kubeAPIServerURL)
152+
config, err = clientcmd.BuildConfigFromFlags(*kubeAPIServerURL, "")
153+
} else {
154+
klog.V(1).Info("Using in-cluster kubeconfig")
155+
config, err = rest.InClusterConfig()
156+
}
157+
if err != nil {
158+
klog.Fatal(err)
159+
}
160+
config.QPS = float32(*clientGoQPS)
161+
config.Burst = *clientGoBurst
162+
return config
163+
}
164+
165+
func runCommand(config *rest.Config) {
166+
client, err := dynamic.NewForConfig(config)
167+
if err != nil {
168+
klog.Fatal(err)
169+
}
170+
171+
gvr := schema.GroupVersionResource{
172+
Group: *commandGroup,
173+
Version: *commandVersion,
174+
Resource: *commandResource,
175+
}
176+
177+
got, err := client.Resource(gvr).
178+
Namespace(*commandNamespace).
179+
Get(
180+
*commandName,
181+
v1.GetOptions{},
182+
)
183+
if err != nil {
184+
klog.Fatal(err)
185+
}
186+
187+
var c types.Command
188+
// convert from unstructured instance to typed instance
189+
err = unstruct.ToTyped(got, &c)
190+
if err != nil {
191+
klog.Fatal(err)
192+
}
193+
194+
cmder, err := command.NewCommander(
195+
command.CommandableConfig{
196+
Command: &c,
197+
},
198+
)
199+
if err != nil {
200+
klog.Fatal(err)
201+
}
202+
status, err := cmder.Run()
203+
if err != nil {
204+
klog.Fatal(err)
205+
}
206+
207+
retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
208+
// Retrieve the latest version of Command before attempting update
209+
// RetryOnConflict uses exponential backoff to avoid exhausting the apiserver
210+
got, err = client.Resource(gvr).
211+
Namespace(*commandNamespace).
212+
Get(
213+
*commandName,
214+
v1.GetOptions{},
215+
)
216+
if err != nil {
217+
klog.Fatal(err)
218+
}
219+
220+
// update labels
221+
lbls := got.GetLabels()
222+
if len(lbls) == 0 {
223+
lbls = make(map[string]string)
224+
}
225+
lbls["command.dope.metacontroller.io/phase"] = string(status.Phase)
226+
got.SetLabels(lbls)
227+
228+
// update status
229+
err = unstructured.SetNestedField(
230+
got.Object,
231+
status,
232+
"status",
233+
)
234+
if err != nil {
235+
klog.Fatal(err)
236+
}
237+
238+
// update command resource
239+
_, updateErr := client.Resource(gvr).
240+
Namespace(*commandNamespace).
241+
Update(
242+
got,
243+
v1.UpdateOptions{},
244+
)
245+
return updateErr
246+
})
247+
if retryErr != nil {
248+
klog.Fatal(retryErr)
249+
}
250+
}

‎controller/command/reconciler.go

+96
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,96 @@
1+
/*
2+
Copyright 2020 The MayaData Authors.
3+
4+
Licensed under the Apache License, Version 2.0 (the "License");
5+
you may not use this file except in compliance with the License.
6+
You may obtain a copy of the License at
7+
8+
https://www.apache.org/licenses/LICENSE-2.0
9+
10+
Unless required by applicable law or agreed to in writing, software
11+
distributed under the License is distributed on an "AS IS" BASIS,
12+
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13+
See the License for the specific language governing permissions and
14+
limitations under the License.
15+
*/
16+
17+
package command
18+
19+
import (
20+
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
21+
"openebs.io/metac/controller/generic"
22+
23+
commonctrl "mayadata.io/d-operators/common/controller"
24+
"mayadata.io/d-operators/common/unstruct"
25+
"mayadata.io/d-operators/pkg/command"
26+
types "mayadata.io/d-operators/types/command"
27+
)
28+
29+
// Reconciler manages reconciliation of Command custom resource
30+
type Reconciler struct {
31+
commonctrl.Reconciler
32+
33+
ObservedCommand *types.Command
34+
Attachment *unstructured.Unstructured
35+
}
36+
37+
func (r *Reconciler) eval() {
38+
var c types.Command
39+
// convert from unstructured instance to typed instance
40+
err := unstruct.ToTyped(r.HookRequest.Watch, &c)
41+
if err != nil {
42+
r.Err = err
43+
return
44+
}
45+
r.ObservedCommand = &c
46+
}
47+
48+
func (r *Reconciler) invoke() {
49+
if r.ObservedCommand.Status.Phase != "" && !r.HookRequest.Attachments.IsEmpty() {
50+
return
51+
}
52+
builder := command.NewJobBuilder(
53+
command.JobBuilderConfig{
54+
Command: *r.ObservedCommand,
55+
},
56+
)
57+
r.Attachment, r.Err = builder.Build()
58+
}
59+
60+
func (r *Reconciler) setSyncResponse() {
61+
if len(r.HookResponse.Attachments) == 0 {
62+
r.HookResponse.SkipReconcile = true
63+
}
64+
65+
if r.ObservedCommand != nil &&
66+
r.ObservedCommand.Spec.Refresh.ResyncAfterSeconds != nil {
67+
r.HookResponse.ResyncAfterSeconds = *r.ObservedCommand.Spec.Refresh.ResyncAfterSeconds
68+
}
69+
}
70+
71+
// Sync implements the idempotent logic to sync Command resource
72+
//
73+
// NOTE:
74+
// SyncHookRequest is the payload received as part of reconcile
75+
// request. Similarly, SyncHookResponse is the payload sent as a
76+
// response as part of reconcile response.
77+
//
78+
// NOTE:
79+
// This controller watches Command custom resource
80+
func Sync(request *generic.SyncHookRequest, response *generic.SyncHookResponse) error {
81+
r := &Reconciler{
82+
Reconciler: commonctrl.Reconciler{
83+
Name: "command-sync-reconciler",
84+
HookRequest: request,
85+
HookResponse: response,
86+
},
87+
}
88+
// add functions to achieve desired state
89+
r.ReconcileFns = []func(){
90+
r.eval,
91+
r.invoke,
92+
r.setSyncResponse,
93+
}
94+
// run reconcile
95+
return r.Reconcile()
96+
}

‎go.mod

+1-2
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@ module mayadata.io/d-operators
33
go 1.13
44

55
require (
6-
9fans.net/go v0.0.2
6+
github.com/go-cmd/cmd v1.2.0
77
github.com/go-resty/resty/v2 v2.2.0
88
github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
99
github.com/google/go-cmp v0.4.0
@@ -13,7 +13,6 @@ require (
1313
k8s.io/apiextensions-apiserver v0.17.3
1414
k8s.io/apimachinery v0.17.3
1515
k8s.io/client-go v0.17.3
16-
k8s.io/klog v1.0.0
1716
k8s.io/klog/v2 v2.0.0
1817
k8s.io/utils v0.0.0-20191114184206-e782cd3c129f
1918
openebs.io/metac v0.3.0

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