Import the Annotation Processor into your build.
with Maven:
<dependency>
<groupId>io.fabric8</groupId>
<artifactId>crd-generator-apt</artifactId>
<scope>provided</scope>
</dependency>
with Gradle:
dependencies {
annotationProcessor 'io.fabric8:crd-generator-apt:<version>'
...
}
Now you can define a class
that extends io.fabric8.kubernetes.client.CustomResource
and the corresponding CRD is generated in the folder: target/classes/META-INF/fabric8
For example, for code similar to:
@Group("org.example")
@Version("v1alpha1")
@ShortNames("ex")
public class Example extends CustomResource<ExampleSpec, ExampleStatus> implements Namespaced {}
public class ExampleSpec {
int someValue;
}
public class ExampleStatus {
boolean error;
String message;
}
Running the compile
task will generate 2 files
target/classes/META-INF/fabric8/examples.org.example-v1.yml
and
target/classes/META-INF/fabric8/examples.org.example-v1beta1.yml
,
the file name is calculated as <plural>.<group>-<CRD spec version>.yml
.
The content of the v1
looks similar to:
apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
name: examples.org.example
spec:
group: org.example
names:
kind: Example
plural: examples
shortNames:
- ex
singular: example
scope: Namespaced
versions:
- name: v1alpha1
schema:
openAPIV3Schema:
properties:
spec:
properties:
someValue:
type: integer
type: object
status:
properties:
error:
type: boolean
message:
type: string
type: object
type: object
served: true
storage: true
subresources:
status: {}
If a field or one of its accessors is annotated with com.fasterxml.jackson.annotation.JsonProperty
public class ExampleSpec {
@JsonProperty("myValue")
int someValue;
}
The generated field in the CRD will be named after the value provided in the annotation instead of using the default name derived from the field name, such as:
spec:
properties:
myValue:
type: integer
type: object
If a field or one of its accessors is annotated with com.fasterxml.jackson.annotation.JsonPropertyDescription
public class ExampleSpec {
@JsonPropertyDescription("This is some value")
int someValue;
}
The generated field in the CRD will preserve the provided description, such as:
spec:
properties:
someValue:
description: This is some value
type: integer
type: object
If a field or one of its accessors is annotated with com.fasterxml.jackson.annotation.JsonIgnore
public class ExampleSpec {
@JsonIgnore
int someValue;
}
The field will be skipped in the generated CRD and will not appear in the schema for this type, such as:
spec:
type: object
If a field or one of its accessors is annotated with javax.validation.constraints.NotNull
public class ExampleSpec {
@NotNull
int someValue;
}
The field will be marked as required
in the generated CRD, such as:
spec:
properties:
someValue:
type: integer
required:
- someValue
type: object
If a field or one of its accessors is annotated with io.fabric8.crd.generator.annotation.SchemaFrom
public class ExampleSpec {
@SchemaFrom(ExampleStatus.class)
int someValue;
}
The CRD generator will substitute the default type inferred from the field and replace it by the computed schema associated with the Java class provided as a value of the SchemaFrom
annotation, as seen below, where ExampleStatus
is the class defined in the example above:
spec:
properties:
someValue:
properties:
error:
type: boolean
message:
type: string
type: object
type: object
If a class is annotated with io.fabric8.crd.generator.annotation.SchemaSwap
@SchemaSwap(originalType = ExampleSpec.class, fieldName = "someValue", targetType = ExampleStatus.class)
public class Example extends CustomResource<ExampleSpec, ExampleStatus> implements Namespaced {}
The CRD generator will perform the same substitution as a SchemaFrom
annotation with value
equal to targetType
was placed on the field named fieldName
in the originalType
class:
spec:
properties:
someValue:
properties:
error:
type: boolean
message:
type: string
type: object
type: object
If a field or one of its accessors is annotated with
com.fasterxml.jackson.annotation.JsonAnyGetter
/com.fasterxml.jackson.annotation.JsonAnySetter
or the field type is com.fasterxml.jackson.databind.JsonNode
public class ExampleSpec {
JsonNode someValue;
@JsonAnyGetter
JsonNode getSomeValue() {
return someValue;
}
@JsonAnySetter
void setSomeValue(JsonNode value) {
this.someValue = value;
}
}
Corresponding x-kubernetes-preserve-unknown-fields: true
will be generated in the output CRD, such as:
spec:
properties:
someValue:
type: object
x-kubernetes-preserve-unknown-fields: true
type: object
x-kubernetes-preserve-unknown-fields: true
Annotation | Description |
---|---|
com.fasterxml.jackson.annotation.JsonProperty |
The field is named after the provided value instead of looking up the java field name |
com.fasterxml.jackson.annotation.JsonPropertyDescription |
The provided text is be embedded in the description of the field |
com.fasterxml.jackson.annotation.JsonIgnore |
The field is ignored |
com.fasterxml.jackson.annotation.JsonAnyGetter |
The corresponding object have x-kubernetes-preserve-unknown-fields: true defined |
com.fasterxml.jackson.annotation.JsonAnySetter |
The corresponding object have x-kubernetes-preserve-unknown-fields: true defined |
javax.validation.constraints.NotNull |
The field is marked as required |
io.fabric8.crd.generator.annotation.SchemaFrom |
The field type for the generation is the one coming from the annotation |
io.fabric8.crd.generator.annotation.SchemaSwap |
Same as SchemaFrom, but can be applied at any point in the class hierarchy |
A field of type com.fasterxml.jackson.databind.JsonNode
is encoded as an empty object with x-kubernetes-preserve-unknown-fields: true
defined.