*: make AlertmanagerConfig v1beta1 an opt-in choice

Enabling by default AlertmanagerConfig v1beta1 by default means that
users would have to configure the conversion webhook and it must be
performed in advance or at the same time users upgrade to the latest
operator version. To offer a smoother transition, we offer
AlertmanagerConfig v1beta1 as an opt-in feature: it's neither included
in the bundle.yaml file nor in the example/prometheus-operator-crd/
manifests.

People that want to enable v1beta1 should use the
example/prometheus-operator-crd-full manifests. For jsonnet users, the
Prometheus operator jsonnet library has a new
`enableAlertmanagerConfigV1beta1` configuration option that can be set
to `true`.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

Makefile

@@ -201,11 +201,17 @@ tidy:
 .PHONY: generate
 generate: $(DEEPCOPY_TARGETS) generate-crds bundle.yaml example/mixin/alerts.yaml example/thanos/thanos.yaml example/admission-webhook example/alertmanager-crd-conversion generate-docs
 
+# For now, the v1beta1 CRDs aren't part of the default bundle because they
+# require to deploy/run the conversion webhook.
+# They are provided in a separate directory
+# (example/prometheus-operator-crd-full) and we generate jsonnet code that can
+# be used to patch the "default" jsonnet CRD.
 .PHONY: generate-crds
 generate-crds: $(CONTROLLER_GEN_BINARY) $(GOJSONTOYAML_BINARY) $(TYPES_V1_TARGET) $(TYPES_V1ALPHA1_TARGET) $(TYPES_V1BETA1_TARGET)
-	cd pkg/apis/monitoring && $(CONTROLLER_GEN_BINARY) crd:crdVersions=v1 paths=./... output:crd:dir=$(PWD)/example/prometheus-operator-crd
+	cd pkg/apis/monitoring && $(CONTROLLER_GEN_BINARY) crd:crdVersions=v1 paths=./v1/. paths=./v1alpha1/. output:crd:dir=$(PWD)/example/prometheus-operator-crd/
 	find example/prometheus-operator-crd/ -name '*.yaml' -print0 | xargs -0 -I{} sh -c '$(GOJSONTOYAML_BINARY) -yamltojson < "$$1" | jq > "$(PWD)/jsonnet/prometheus-operator/$$(basename $$1 | cut -d'_' -f2 | cut -d. -f1)-crd.json"' -- {}
-
+	cd pkg/apis/monitoring && $(CONTROLLER_GEN_BINARY) crd:crdVersions=v1 paths=./... output:crd:dir=$(PWD)/example/prometheus-operator-crd-full
+	echo "{spec+: {versions+: $$($(GOJSONTOYAML_BINARY) -yamltojson < example/prometheus-operator-crd-full/monitoring.coreos.com_alertmanagerconfigs.yaml | jq '.spec.versions | map(select(.name == "v1beta1"))')}}" | $(JSONNETFMT_BINARY) - > $(PWD)/jsonnet/prometheus-operator/alertmanagerconfigs-v1beta1-crd.libsonnet
 
 .PHONY: generate-remote-write-certs
 generate-remote-write-certs:
@@ -247,8 +253,11 @@ TO_BE_EXTENDED_DOCS = $(filter-out $(FULLY_GENERATED_DOCS), $(shell find Documen
 Documentation/operator.md: operator
 	$(MDOX_BINARY) fmt $@
 
-Documentation/api.md: $(PO_DOCGEN_BINARY) $(TYPES_V1_TARGET) $(TYPES_V1ALPHA1_TARGET) $(TYPES_V1BETA1_TARGET)
-	$(PO_DOCGEN_BINARY) api $(TYPES_V1_TARGET) $(TYPES_V1ALPHA1_TARGET) $(TYPES_V1BETA1_TARGET) > $@
+# For now, the v1beta1 CRDs aren't part of the default bundle because they
+# require to deploy/run the conversion webhook. As a consequence, they are not
+# yet included in the API documentation.
+Documentation/api.md: $(PO_DOCGEN_BINARY) $(TYPES_V1_TARGET) $(TYPES_V1ALPHA1_TARGET)
+	$(PO_DOCGEN_BINARY) api $(TYPES_V1_TARGET) $(TYPES_V1ALPHA1_TARGET) > $@
 
 Documentation/compatibility.md: $(PO_DOCGEN_BINARY) pkg/prometheus/statefulset.go
 	$(PO_DOCGEN_BINARY) compatibility > $@

example/prometheus-operator-crd-full/monitoring.coreos.com_prometheusrules.yaml

@@ -0,0 +1,103 @@
+---
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  annotations:
+    controller-gen.kubebuilder.io/version: v0.8.0
+  creationTimestamp: null
+  name: prometheusrules.monitoring.coreos.com
+spec:
+  group: monitoring.coreos.com
+  names:
+    categories:
+    - prometheus-operator
+    kind: PrometheusRule
+    listKind: PrometheusRuleList
+    plural: prometheusrules
+    shortNames:
+    - promrule
+    singular: prometheusrule
+  scope: Namespaced
+  versions:
+  - name: v1
+    schema:
+      openAPIV3Schema:
+        description: PrometheusRule defines recording and alerting rules for a Prometheus
+          instance
+        properties:
+          apiVersion:
+            description: 'APIVersion defines the versioned schema of this representation
+              of an object. Servers should convert recognized schemas to the latest
+              internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources'
+            type: string
+          kind:
+            description: 'Kind is a string value representing the REST resource this
+              object represents. Servers may infer this from the endpoint the client
+              submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds'
+            type: string
+          metadata:
+            type: object
+          spec:
+            description: Specification of desired alerting rule definitions for Prometheus.
+            properties:
+              groups:
+                description: Content of Prometheus rule file
+                items:
+                  description: 'RuleGroup is a list of sequentially evaluated recording
+                    and alerting rules. Note: PartialResponseStrategy is only used
+                    by ThanosRuler and will be ignored by Prometheus instances.  Valid
+                    values for this field are ''warn'' or ''abort''.  More info: https://github.com/thanos-io/thanos/blob/main/docs/components/rule.md#partial-response'
+                  properties:
+                    interval:
+                      type: string
+                    name:
+                      type: string
+                    partial_response_strategy:
+                      type: string
+                    rules:
+                      items:
+                        description: 'Rule describes an alerting or recording rule
+                          See Prometheus documentation: [alerting](https://www.prometheus.io/docs/prometheus/latest/configuration/alerting_rules/)
+                          or [recording](https://www.prometheus.io/docs/prometheus/latest/configuration/recording_rules/#recording-rules)
+                          rule'
+                        properties:
+                          alert:
+                            type: string
+                          annotations:
+                            additionalProperties:
+                              type: string
+                            type: object
+                          expr:
+                            anyOf:
+                            - type: integer
+                            - type: string
+                            x-kubernetes-int-or-string: true
+                          for:
+                            type: string
+                          labels:
+                            additionalProperties:
+                              type: string
+                            type: object
+                          record:
+                            type: string
+                        required:
+                        - expr
+                        type: object
+                      type: array
+                  required:
+                  - name
+                  - rules
+                  type: object
+                type: array
+            type: object
+        required:
+        - spec
+        type: object
+    served: true
+    storage: true
+status:
+  acceptedNames:
+    kind: ""
+    plural: ""
+  conditions: []
+  storedVersions: []