Add helper function to resolve jsonpath

pkg/jsonpath/jsonpath.go

@@ -0,0 +1,55 @@
+// Copyright 2021 The Kanister Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package jsonpath
+
+import (
+	"bytes"
+	"regexp"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/cli-runtime/pkg/printers"
+)
+
+// jsonpathRegex represents pattern in which jsonpath is specified in the wait conditions
+// e.g { $.status.phase }
+var jsonpathRegex = regexp.MustCompile(`(?m){\s*\$([^}]*)`)
+
+// FindJsonpathArgs returns matched jsonpath args in the string
+func FindJsonpathArgs(s string) map[string]string {
+	matchMap := make(map[string]string)
+	for _, matchList := range jsonpathRegex.FindAllSubmatch([]byte(s), -1) {
+		matchedSource := ""
+		for i := range matchList {
+			if i == 0 {
+				// Add ending "}" excluded by regex
+				matchedSource = string(matchList[i]) + "}"
+				continue
+			}
+			matchMap[matchedSource] = string(matchList[i])
+		}
+	}
+	return matchMap
+}
+
+// ResolveJsonpath resolves jsonpath value from the k8s resource object
+func ResolveJsonpathToString(obj runtime.Object, jsonpathStr string) (string, error) {
+	var buff bytes.Buffer
+	jp, err := printers.NewJSONPathPrinter(jsonpathStr)
+	if err != nil {
+		return "", nil
+	}
+	err = jp.PrintObj(obj, &buff)
+	return buff.String(), err
+}

pkg/jsonpath/jsonpath_test.go

@@ -0,0 +1,174 @@
+// Copyright 2021 The Kanister Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package jsonpath
+
+import (
+	"testing"
+
+	. "gopkg.in/check.v1"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/kubernetes/scheme"
+)
+
+// Hook up gocheck into the "go test" runner.
+func Test(t *testing.T) { TestingT(t) }
+
+type JsonpathSuite struct{}
+
+var _ = Suite(&JsonpathSuite{})
+
+const deploy = `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  annotations:
+    deployment.kubernetes.io/revision: "1"
+  creationTimestamp: "2021-08-30T14:43:29Z"
+  generation: 1
+  name: test-deployment
+  namespace: test
+  resourceVersion: "2393578"
+  uid: 13b876a9-440f-45ba-8e5f-fea8167b5dc9
+spec:
+  progressDeadlineSeconds: 600
+  replicas: 3
+  revisionHistoryLimit: 10
+  selector:
+    matchLabels:
+      app: demo
+  strategy:
+    rollingUpdate:
+      maxSurge: 25%
+      maxUnavailable: 25%
+    type: RollingUpdate
+  template:
+    metadata:
+      creationTimestamp: null
+      labels:
+        app: demo
+    spec:
+      containers:
+      - image: nginx:1.12
+        imagePullPolicy: IfNotPresent
+        name: web
+        ports:
+        - containerPort: 80
+          name: http
+          protocol: TCP
+        resources: {}
+        terminationMessagePath: /dev/termination-log
+        terminationMessagePolicy: File
+      dnsPolicy: ClusterFirst
+      restartPolicy: Always
+      schedulerName: default-scheduler
+      securityContext: {}
+      terminationGracePeriodSeconds: 30
+status:
+  availableReplicas: 3
+  conditions:
+  - lastTransitionTime: "2021-08-30T14:43:31Z"
+    lastUpdateTime: "2021-08-30T14:43:31Z"
+    message: Deployment has minimum availability.
+    reason: MinimumReplicasAvailable
+    status: "True"
+    type: Available
+  - lastTransitionTime: "2021-08-30T14:43:29Z"
+    lastUpdateTime: "2021-08-30T14:43:31Z"
+    message: ReplicaSet "test-deployment-6b4d4fbcdb" has successfully progressed.
+    reason: NewReplicaSetAvailable
+    status: "True"
+    type: Progressing
+  observedGeneration: 1
+  readyReplicas: 3
+  replicas: 3
+  updatedReplicas: 3
+`
+
+func runtimeObjFromYAML(c *C, specs string) runtime.Object {
+	decode := scheme.Codecs.UniversalDeserializer().Decode
+	obj, _, err := decode([]byte(specs), nil, nil)
+	c.Assert(err, IsNil)
+	return obj
+}
+
+func (js *JsonpathSuite) TestDeploymentReady(c *C) {
+	obj := runtimeObjFromYAML(c, deploy)
+	replica, err := ResolveJsonpathToString(obj, "{.spec.replicas}")
+	c.Assert(err, IsNil)
+	c.Assert(replica, Equals, "3")
+
+	readyReplicas, err := ResolveJsonpathToString(obj, "{.status.replicas}")
+	c.Assert(err, IsNil)
+	c.Assert(readyReplicas, Equals, "3")
+
+	availReplicas, err := ResolveJsonpathToString(obj, "{.status.availableReplicas}")
+	c.Assert(err, IsNil)
+	c.Assert(availReplicas, Equals, "3")
+
+	// Any condition with type Available
+	condType, err := ResolveJsonpathToString(obj, `{.status.conditions[?(@.type == "Available")].type}`)
+	c.Assert(err, IsNil)
+	c.Assert(condType, Equals, "Available")
+
+	condStatus, err := ResolveJsonpathToString(obj, `{.status.conditions[?(@.type == "Available")].status}`)
+	c.Assert(err, IsNil)
+	c.Assert(condStatus, Equals, "True")
+
+	_, err = ResolveJsonpathToString(obj, "{.status.something}")
+	c.Assert(err, NotNil)
+}
+
+func (js *JsonpathSuite) TestFindJsonpathArgs(c *C) {
+	for _, tc := range []struct {
+		arg            string
+		expJsonpathArg map[string]string
+	}{
+		{
+			arg: "{{ if (eq {$.spec.replicas} { $.status.replicas } )}}true{{ else }}false{{ end }}",
+			expJsonpathArg: map[string]string{
+				"{$.spec.replicas}":     ".spec.replicas",
+				"{ $.status.replicas }": ".status.replicas ",
+			},
+		},
+		{
+			arg: `{{ if and (eq {$.spec.replicas} {$.status.availableReplicas} )
+				(and (eq "{ $.status.conditions[?(@.type == "Available")].type }" "Available")
+				(eq "{ $.status.conditions[?(@.type == "Available")].status }" "True"))}}
+				true
+				{{ else }}
+				false
+				{{ end }}`,
+			expJsonpathArg: map[string]string{
+				"{$.spec.replicas}":                                          ".spec.replicas",
+				"{$.status.availableReplicas}":                               ".status.availableReplicas",
+				"{ $.status.conditions[?(@.type == \"Available\")].type }":   ".status.conditions[?(@.type == \"Available\")].type ",
+				"{ $.status.conditions[?(@.type == \"Available\")].status }": ".status.conditions[?(@.type == \"Available\")].status ",
+			},
+		},
+		{
+			arg: "{{ if (eq {$.book[?(@.price<10).quantity} 10 )}}true{{ else }}false{{ end }}",
+			expJsonpathArg: map[string]string{
+				"{$.book[?(@.price<10).quantity}": ".book[?(@.price<10).quantity",
+			},
+		},
+		{
+			arg:            "{{ if (eq .Book.Quantity} 10 )}}true{{ else }}false{{ end }}",
+			expJsonpathArg: map[string]string{},
+		},
+	} {
+		m := FindJsonpathArgs(tc.arg)
+		c.Assert(m, DeepEquals, tc.expJsonpathArg)
+	}
+}