Add Container object to environment build and runtime specs (#413)

Environment Specs so far had only an image URL to specify a container image.

This was fine for public images but fell short in a few of cases:
(a) Using private image registries
(b) Specifying environment variables (this is needed for workflows helm install)
(c) Setting a SecurityContext for the container

This change adds the Container object to both build and runtime Environments. 

Compatibility is preserved -- the existing ImageURL field is still used.  See the comments in types.go for the overriding rules in the case that both Container and ImageURL are specified.

merge_test.go

@@ -0,0 +1,120 @@
+/*
+Copyright 2016 The Fission 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 fission
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	apiv1 "k8s.io/client-go/pkg/api/v1"
+)
+
+func TestMergeContainerSpecs(t *testing.T) {
+	expected := apiv1.Container{
+		Name:  "containerName",
+		Image: "testImage",
+		Command: []string{
+			"command",
+		},
+		Args: []string{
+			"arg1",
+			"arg2",
+		},
+		ImagePullPolicy: apiv1.PullNever,
+		TTY:             true,
+		Env: []apiv1.EnvVar{
+			{
+				Name:  "a",
+				Value: "b",
+			},
+			{
+				Name:  "c",
+				Value: "d",
+			},
+		},
+	}
+	specs := []*apiv1.Container{
+		{
+			Name:  "containerName",
+			Image: "testImage",
+			Command: []string{
+				"command",
+			},
+			Args: []string{
+				"arg1",
+				"arg2",
+			},
+			ImagePullPolicy: apiv1.PullNever,
+			TTY:             true,
+		},
+		{
+			Name:  "shouldNotBeThere",
+			Image: "shouldNotBeThere",
+			Env: []apiv1.EnvVar{
+				{
+					Name:  "a",
+					Value: "b",
+				},
+			},
+			ImagePullPolicy: apiv1.PullAlways,
+			TTY:             false,
+		},
+		{
+			Env: []apiv1.EnvVar{
+				{
+					Name:  "c",
+					Value: "d",
+				},
+			},
+			ImagePullPolicy: apiv1.PullIfNotPresent,
+			TTY:             false,
+		},
+	}
+	result := MergeContainerSpecs(specs...)
+	assert.Equal(t, expected, result)
+
+	// Check if merging order actually matters
+	var rspecs []*apiv1.Container
+	for i := len(specs) - 1; i >= 0; i -= 1 {
+		rspecs = append(rspecs, specs[i])
+	}
+	reverseResult := MergeContainerSpecs(rspecs...)
+	assert.NotEqual(t, expected, reverseResult)
+}
+
+func TestMergeContainerSpecsSingle(t *testing.T) {
+	expected := apiv1.Container{
+		Name:  "containerName",
+		Image: "testImage",
+		Command: []string{
+			"command",
+		},
+		Args: []string{
+			"arg1",
+			"arg2",
+		},
+		ImagePullPolicy: apiv1.PullNever,
+		TTY:             true,
+	}
+	result := MergeContainerSpecs(&expected)
+	assert.EqualValues(t, expected, result)
+}
+
+func TestMergeContainerSpecsNil(t *testing.T) {
+	expected := apiv1.Container{}
+	result := MergeContainerSpecs()
+	assert.EqualValues(t, expected, result)
+}