jsonnet: add function to apply platform patches

Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>

jsonnet/kube-prometheus/main.libsonnet

@@ -9,6 +9,8 @@ local prometheusAdapter = import './components/prometheus-adapter.libsonnet';
 local prometheusOperator = import './components/prometheus-operator.libsonnet';
 local prometheus = import './components/prometheus.libsonnet';
 
+local platformPatch = (import './platforms/platforms.libsonnet').platformPatch;
+
 {
   // using `values` as this is similar to helm
   values:: {
@@ -104,6 +106,7 @@ local prometheus = import './components/prometheus.libsonnet';
     kubePrometheus: {
       namespace: $.values.common.namespace,
       mixin+: { ruleLabels: $.values.common.ruleLabels },
+      platform: null,
     },
   },
 
@@ -124,5 +127,5 @@ local prometheus = import './components/prometheus.libsonnet';
         name: $.values.kubePrometheus.namespace,
       },
     },
-  },
+  } + platformPatch($.values.kubePrometheus.platform),
 }

jsonnet/kube-prometheus/platforms/README.md

@@ -0,0 +1,18 @@
+# Adding a new platform specific configuration
+
+Adding a new platform specific configuration requires to update the
+[platforms.jsonnet](./platform.jsonnet) file by adding the platform to the list
+of existing ones.
+
+This allow configuring the new platform in the following way:
+
+```jsonnet
+(import 'kube-prometheus/main.libsonnet') +
+  {
+    values+:: {
+      kubePrometheus+: {
+        platform: 'example-platform',
+      }
+    }
+  }
+```

jsonnet/kube-prometheus/platforms/platforms.libsonnet

@@ -0,0 +1,16 @@
+local platforms = {
+  aws: import './aws.libsonnet',
+  bootkube: import './bootkube.libsonnet',
+  gke: import './gke.libsonnet',
+  eks: import './eks.libsonnet',
+  kops: import './kops.libsonnet',
+  kops_coredns: (import './kops.libsonnet') + (import './kops-coredns.libsonnet'),
+  kubeadm: import './kubeadm.libsonnet',
+  kubespray: import './kubespray.libsonnet',
+};
+
+{
+  // platformPatch returns the platform specific patch associated to the given
+  // platform.
+  platformPatch(p): if p != null && std.objectHas(platforms, p) then platforms[p] else {},
+}