Apache License

http://www.apache.org/licenses/LICENSE-2.0

package v1

Imports

import (
	batchv1 "k8s.io/api/batch/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// EDIT THIS FILE!  THIS IS SCAFFOLDING FOR YOU TO OWN!
// NOTE: json tags are required.  Any new fields you add must have json tags for the fields to be serialized.

First, let’s take a look at our spec. As we discussed before, spec holds desired state, so any “inputs” to our controller go here.

Fundamentally a CronJob needs the following pieces:

• A schedule (the cron in CronJob)
• A template for the Job to run (the job in CronJob)

We’ll also want a few extras, which will make our users’ lives easier:

• A deadline for starting jobs (if we miss this deadline, we’ll just wait till the next scheduled time)
• What to do if multiple jobs would run at once (do we wait? stop the old one? run both?)
• A way to pause the running of a CronJob, in case something’s wrong with it
• Limits on old job history

Remember, since we never read our own status, we need to have some other way to keep track of whether a job has run. We can use at least one old job to do this.

We’ll use several markers (// +comment) to specify additional metadata. These will be used by controller-tools when generating our CRD manifest. As we’ll see in a bit, controller-tools will also use GoDoc to form descriptions for the fields.

// CronJobSpec defines the desired state of CronJob.
type CronJobSpec struct {
	// +kubebuilder:validation:MinLength=0

	// The schedule in Cron format, see https://en.wikipedia.org/wiki/Cron.
	Schedule string `json:"schedule"`

	// +kubebuilder:validation:Minimum=0

	// Optional deadline in seconds for starting the job if it misses scheduled
	// time for any reason.  Missed jobs executions will be counted as failed ones.
	// +optional
	StartingDeadlineSeconds *int64 `json:"startingDeadlineSeconds,omitempty"`

	// Specifies how to treat concurrent executions of a Job.
	// Valid values are:
	// - "Allow" (default): allows CronJobs to run concurrently;
	// - "Forbid": forbids concurrent runs, skipping next run if previous run hasn't finished yet;
	// - "Replace": cancels currently running job and replaces it with a new one
	// +optional
	ConcurrencyPolicy ConcurrencyPolicy `json:"concurrencyPolicy,omitempty"`

	// This flag tells the controller to suspend subsequent executions, it does
	// not apply to already started executions.  Defaults to false.
	// +optional
	Suspend *bool `json:"suspend,omitempty"`

	// Specifies the job that will be created when executing a CronJob.
	JobTemplate batchv1.JobTemplateSpec `json:"jobTemplate"`

	// +kubebuilder:validation:Minimum=0

	// The number of successful finished jobs to retain.
	// This is a pointer to distinguish between explicit zero and not specified.
	// +optional
	SuccessfulJobsHistoryLimit *int32 `json:"successfulJobsHistoryLimit,omitempty"`

	// +kubebuilder:validation:Minimum=0

	// The number of failed finished jobs to retain.
	// This is a pointer to distinguish between explicit zero and not specified.
	// +optional
	FailedJobsHistoryLimit *int32 `json:"failedJobsHistoryLimit,omitempty"`
}

We define a custom type to hold our concurrency policy. It’s actually just a string under the hood, but the type gives extra documentation, and allows us to attach validation on the type instead of the field, making the validation more easily reusable.

// ConcurrencyPolicy describes how the job will be handled.
// Only one of the following concurrent policies may be specified.
// If none of the following policies is specified, the default one
// is AllowConcurrent.
// +kubebuilder:validation:Enum=Allow;Forbid;Replace
type ConcurrencyPolicy string

const (
	// AllowConcurrent allows CronJobs to run concurrently.
	AllowConcurrent ConcurrencyPolicy = "Allow"

	// ForbidConcurrent forbids concurrent runs, skipping next run if previous
	// hasn't finished yet.
	ForbidConcurrent ConcurrencyPolicy = "Forbid"

	// ReplaceConcurrent cancels currently running job and replaces it with a new one.
	ReplaceConcurrent ConcurrencyPolicy = "Replace"
)

Next, let’s design our status, which holds observed state. It contains any information we want users or other controllers to be able to easily obtain.

We’ll keep a list of actively running jobs, as well as the last time that we successfully ran our job. Notice that we use metav1.Time instead of time.Time to get the stable serialization, as mentioned above.

// CronJobStatus defines the observed state of CronJob.
type CronJobStatus struct {
	// INSERT ADDITIONAL STATUS FIELD - define observed state of cluster
	// Important: Run "make" to regenerate code after modifying this file

	// A list of pointers to currently running jobs.
	// +optional
	Active []corev1.ObjectReference `json:"active,omitempty"`

	// Information when was the last time the job was successfully scheduled.
	// +optional
	LastScheduleTime *metav1.Time `json:"lastScheduleTime,omitempty"`
}

Finally, we have the rest of the boilerplate that we’ve already discussed. As previously noted, we don’t need to change this, except to mark that we want a status subresource, so that we behave like built-in kubernetes types.

// +kubebuilder:object:root=true
// +kubebuilder:subresource:status

// CronJob is the Schema for the cronjobs API.
type CronJob struct {

Root Object Definitions

	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	Spec   CronJobSpec   `json:"spec,omitempty"`
	Status CronJobStatus `json:"status,omitempty"`
}

// +kubebuilder:object:root=true

// CronJobList contains a list of CronJob.
type CronJobList struct {
	metav1.TypeMeta `json:",inline"`
	metav1.ListMeta `json:"metadata,omitempty"`
	Items           []CronJob `json:"items"`
}

func init() {
	SchemeBuilder.Register(&CronJob{}, &CronJobList{})
}