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Add new --wait-for-creation flag in kubectl wait command

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kubectl wait command errors out when the waited resource does not exist.
But we need to provide a way to the users about intentionally also waiting for
the creation of resources.

This PR introduces a new flag to cover waiting for the creation of resources
with preserving the default behavior.
This commit is contained in:
Arda Güçlü
2024-01-26 15:53:55 +03:00
parent 8565e37525
commit e24b9a022f
3 changed files with 158 additions and 13 deletions
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45
staging/src/k8s.io/kubectl/pkg/cmd/wait/wait.go
View File

@@ -82,7 +82,10 @@ var (
# Wait for the pod "busybox1" to be deleted, with a timeout of 60s, after having issued the "delete" command
kubectl delete pod/busybox1
kubectl wait --for=delete pod/busybox1 --timeout=60s`))
kubectl wait --for=delete pod/busybox1 --timeout=60s
# Wait for the creation of the service "loadbalancer" in addition to wait to have ingress
kubectl wait --for=jsonpath='{.status.loadBalancer.ingress}' service/loadbalancer --wait-for-creation`))
)
// errNoMatchingResources is returned when there is no resources matching a query.
@@ -98,6 +101,7 @@ type WaitFlags struct {
Timeout time.Duration
ForCondition string
WaitForCreation bool
genericiooptions.IOStreams
}
@@ -116,6 +120,7 @@ func NewWaitFlags(restClientGetter genericclioptions.RESTClientGetter, streams g
WithLatest(),
Timeout: 30 * time.Second,
WaitForCreation: true,
IOStreams: streams,
}
@@ -152,6 +157,7 @@ func (flags *WaitFlags) AddFlags(cmd *cobra.Command) {
cmd.Flags().DurationVar(&flags.Timeout, "timeout", flags.Timeout, "The length of time to wait before giving up. Zero means check once and don't wait, negative means wait for a week.")
cmd.Flags().StringVar(&flags.ForCondition, "for", flags.ForCondition, "The condition to wait on: [delete|condition=condition-name[=condition-value]|jsonpath='{JSONPath expression}'=[JSONPath value]]. The default condition-value is true. Condition values are compared after Unicode simple case folding, which is a more general form of case-insensitivity.")
cmd.Flags().BoolVar(&flags.WaitForCreation, "wait-for-creation", flags.WaitForCreation, "The default value is true. If set to true, also wait for creation of objects if they do not already exist. This flag is ignored in --for=delete")
}
// ToOptions converts from CLI inputs to runtime inputs
@@ -184,6 +190,7 @@ func (flags *WaitFlags) ToOptions(args []string) (*WaitOptions, error) {
DynamicClient: dynamicClient,
Timeout: effectiveTimeout,
ForCondition: flags.ForCondition,
WaitForCreation: flags.WaitForCreation,
Printer: printer,
ConditionFn: conditionFn,
@@ -306,6 +313,7 @@ type WaitOptions struct {
DynamicClient dynamic.Interface
Timeout time.Duration
ForCondition string
WaitForCreation bool
Printer printers.ResourcePrinter
ConditionFn ConditionFunc
@@ -320,6 +328,40 @@ func (o *WaitOptions) RunWait() error {
ctx, cancel := watchtools.ContextWithOptionalTimeout(context.Background(), o.Timeout)
defer cancel()
isForDelete := strings.ToLower(o.ForCondition) == "delete"
if o.WaitForCreation && o.Timeout == 0 {
return fmt.Errorf("--wait-for-creation requires a timeout value greater than 0")
}
if o.WaitForCreation && !isForDelete {
err := func() error {
for {
select {
case <-ctx.Done():
return fmt.Errorf("context deadline is exceeded while waiting for the creation of the resources")
default:
err := o.ResourceFinder.Do().Visit(func(info *resource.Info, err error) error {
// We don't need to do anything after we assure that the resources exist. Because
// actual logic will be incorporated after we wait all the resources' existence.
return nil
})
// It is verified that all the resources exist.
if err == nil {
return nil
}
// We specifically wait for the creation of resources and all the errors
// other than not found means that this is something we cannot handle.
if !apierrors.IsNotFound(err) {
return err
}
}
}
}()
if err != nil {
return err
}
}
visitCount := 0
visitFunc := func(info *resource.Info, err error) error {
if err != nil {
@@ -338,7 +380,6 @@ func (o *WaitOptions) RunWait() error {
return err
}
visitor := o.ResourceFinder.Do()
isForDelete := strings.ToLower(o.ForCondition) == "delete"
if visitor, ok := visitor.(*resource.Result); ok && isForDelete {
visitor.IgnoreErrors(apierrors.IsNotFound)
}

1
test/cmd/legacy-script.sh
View File

@@ -1036,6 +1036,7 @@ runTests() {
####################
record_command run_wait_tests
record_command run_wait_with_non_existence_check_tests
####################
# kubectl debug #

103
test/cmd/wait.sh
View File

@@ -117,3 +117,106 @@ EOF
set +o nounset
set +o errexit
}
run_wait_with_non_existence_check_tests() {
set -o nounset
set -o errexit
kube::log::status "Testing kubectl wait"
create_and_use_new_namespace
### Wait for deletion using --all flag
# create test data
kubectl create deployment test-1 --image=busybox
kubectl create deployment test-2 --image=busybox
# Post-Condition: deployments exists
kube::test::get_object_assert "deployments" "{{range .items}}{{.metadata.name}},{{end}}" 'test-1,test-2,'
# wait with jsonpath will timout for busybox deployment
set +o errexit
# Command: Wait with jsonpath support fields not exist in the first place
output_message=$(kubectl wait --wait-for-creation --for=jsonpath=.status.readyReplicas=1 deploy/test-1 2>&1)
set -o errexit
# Post-Condition: Wait failed
kube::test::if_has_string "${output_message}" 'timed out'
# Delete all deployments async to kubectl wait
( sleep 2 && kubectl delete deployment --all ) &
# Command: Wait for all deployments to be deleted
output_message=$(kubectl wait deployment --for=delete --all)
# Post-Condition: Wait was successful
kube::test::if_has_string "${output_message}" 'test-1 condition met'
kube::test::if_has_string "${output_message}" 'test-2 condition met'
# create test data to test timeout error is occurred in correct time
kubectl apply -f - <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: dtest
name: dtest
spec:
replicas: 3
selector:
matchLabels:
app: dtest
template:
metadata:
labels:
app: dtest
spec:
containers:
- name: bb
image: busybox
command: ["/bin/sh", "-c", "sleep infinity"]
EOF
set +o errexit
# wait timeout error because condition is invalid
start_sec=$(date +"%s")
output_message=$(time kubectl wait pod --wait-for-creation --selector=app=dtest --for=condition=InvalidCondition --timeout=1s 2>&1)
end_sec=$(date +"%s")
len_sec=$((end_sec-start_sec))
set -o errexit
kube::test::if_has_string "${output_message}" 'timed out waiting for the condition '
test $len_sec -ge 1 && test $len_sec -le 2
# Clean deployment
kubectl delete deployment dtest
# create test data
kubectl create deployment test-3 --image=busybox
# wait with jsonpath without value to succeed
set +o errexit
# Command: Wait with jsonpath without value
output_message_0=$(kubectl wait --wait-for-creation --for=jsonpath='{.status.replicas}' deploy/test-3 2>&1)
# Command: Wait with relaxed jsonpath and filter expression
output_message_1=$(kubectl wait \
--for='jsonpath=spec.template.spec.containers[?(@.name=="busybox")].image=busybox' \
deploy/test-3)
set -o errexit
# Post-Condition: Wait succeed
kube::test::if_has_string "${output_message_0}" 'deployment.apps/test-3 condition met'
kube::test::if_has_string "${output_message_1}" 'deployment.apps/test-3 condition met'
# Clean deployment
kubectl delete deployment test-3
( sleep 3 && kubectl create deployment test-4 --image=busybox ) &
output_message=$(kubectl wait --wait-for-creation --for=jsonpath=.status.replicas=1 deploy/test-4 2>&1)
kube::test::if_has_string "${output_message}" 'test-4 condition met'
kubectl delete deployment test-4
set +o nounset
set +o errexit
}