feat: make environment context available (#832)

* feat: make environment context available

This feature adds the "{{.Environment.KubeContext}}" variable.

Discussion #829

Signed-off-by: sewieland <sebastian.wieland@iav.de>

* chore: fix tests which compare logging outputs

This commit adds an addtional space wherever needed to the expected log outputs due to the added "KubeContext" in the environment struct.

Discussion #829

Signed-off-by: Sebastian Wieland <wieland.s@mailbox.org>

* docs: added documentation for `Environment.KubeContext`

Discussion #829

Signed-off-by: Sebastian Wieland <wieland.s@mailbox.org>

* test: make sure the `Environment.KubeContext` is mapped out correctly

Discussion #829

Signed-off-by: Sebastian Wieland <wieland.s@mailbox.org>

---------

Signed-off-by: sewieland <sebastian.wieland@iav.de>
Signed-off-by: Sebastian Wieland <wieland.s@mailbox.org>
Co-authored-by: sewieland <sebastian.wieland@iav.de>

docs/builtin-objects.md

@@ -3,13 +3,14 @@
 - `Environment`: The information about the environment. This is set by the
   `--environment` flag. It has several objects inside of it:
   - `Environment.Name`: The name of the environment
+  - `Environment.KubeContext`: The kube context to be used by default for releases in the environment.
 - `Values`: Values passed into the environment.
 - `StateValues`: alias for `Values`.
 - `Namespace`: The namespace to be released into
 
 # release template built-in objects
 
-it be used for the below tow cases:
+it be used for the below two cases:
 
 1. release definition
 ```
@@ -56,6 +57,7 @@ releases:
 - `Environment`: The information about the environment. This is set by the
   `--environment` flag. It has several objects inside of it:
   - `Environment.Name`: The name of the environment
+  - `Environment.KubeContext`: The kube context to be used by default for releases in the environment.
 - `Chart`: The chart name for the release.
 - `KubeContext`: The kube context to be used for the release
 - `Namespace`: The namespace to be released into

docs/index.md

@@ -1353,6 +1353,67 @@ releases:
 For templating, imagine that you created a hook that generates a helm chart on-the-fly by running an external tool like ksonnet, kustomize, or your own template engine.
 It will allow you to write your helm releases with any language you like, while still leveraging goodies provided by helm.
 
+### Hooks, Kubectl and Environments
+
+Hooks can also be used in combination with small tasks using `kubectl` directly,
+e.g.: in order to install a custom storage class.
+
+In the following example, a specific release depends on a custom storage class.
+Further, all enviroments have a default kube context configured where releases are deployed into.
+The `.Environment.KubeContext` is used in order to apply / remove the YAML to the correct context depending on the environment.
+
+`environments.yaml`:
+
+```yaml
+environments:
+  dev:
+    values:
+    - ../values/default.yaml
+    - ../values/dev.yaml
+    kubeContext: dev-cluster
+  prod:
+    values:
+    - ../values/default.yaml
+    - ../values/prod.yaml
+    kubeContext: prod-cluster
+```
+
+`helmfile.yaml`:
+
+```yaml
+bases:
+  - ./environments.yaml
+
+---
+releases:
+  - name: myService
+    namespace: my-ns
+    installed: true
+    chart: mychart
+    version: "1.2.3"
+    values:
+      - ../services/my-service/values.yaml.gotmpl
+    hooks:
+      - events: ["presync"]
+        showlogs: true
+        command: "kubectl"
+        args:
+          - "apply"
+          - "-f"
+          - "./custom-storage-class.yaml"
+          - "--context"
+          - "{{`{{.Environment.KubeContext}}`}}"
+      - events: ["postuninstall"]
+        showlogs: true
+        command: "kubectl"
+        args:
+          - "delete"
+          - "-f"
+          - "./custom-storage-class.yaml"
+          - "--context"
+          - "{{`{{.Environment.KubeContext}}`}}"
+```
+
 ### Global Hooks
 
 In contrast to the per release hooks mentioned above these are run only once at the very beginning and end of the execution of a helmfile command and only the `prepare` and `cleanup` hooks are available respectively.

pkg/environment/environment.go

@@ -9,6 +9,7 @@ import (
 
 type Environment struct {
 	Name        string
+	KubeContext string
 	Values      map[string]interface{}
 	Defaults    map[string]interface{}
 }
@@ -19,6 +20,7 @@ var EmptyEnvironment Environment
 func New(name string) *Environment {
 	return &Environment{
 		Name:        name,
+		KubeContext: "",
 		Values:      map[string]interface{}{},
 		Defaults:    map[string]interface{}{},
 	}
@@ -53,6 +55,7 @@ func (e Environment) DeepCopy() Environment {
 
 	return Environment{
 		Name:        e.Name,
+		KubeContext: e.KubeContext,
 		Values:      values,
 		Defaults:    defaults,
 	}

pkg/state/create.go

@@ -252,7 +252,7 @@ func (c *StateCreator) loadEnvValues(st *HelmState, name string, failOnMissingEn
 		return nil, &UndefinedEnvError{msg: fmt.Sprintf("environment \"%s\" is not defined", name)}
 	}
 
-	newEnv := &environment.Environment{Name: name, Values: envVals}
+	newEnv := &environment.Environment{Name: name, Values: envVals, KubeContext: envSpec.KubeContext}
 
 	if ctxEnv != nil {
 		intCtxEnv := *ctxEnv

pkg/state/create_test.go

@@ -489,3 +489,58 @@ func TestReadFromYaml_Helmfiles_Selectors(t *testing.T) {
 		require.Equalf(t, test.helmfiles, st.Helmfiles, "for path %s", test.path)
 	}
 }
+
+func TestReadFromYaml_EnvironmentContext(t *testing.T) {
+	yamlFile := "/example/path/to/helmfile.yaml"
+	yamlContent := []byte(`environments:
+  production:
+    values: []
+    kubeContext: myCtx
+
+releases:
+- name: myrelease
+  namespace: mynamespace
+  chart: mychart
+  values:
+  - values.yaml.gotmpl
+`)
+
+	valuesFile := "/example/path/to/values.yaml.gotmpl"
+	valuesContent := []byte(`envName: {{ .Environment.Name }}
+envContext: {{ .Environment.KubeContext }}
+releaseName: {{ .Release.Name }}
+releaseContext: {{ .Release.KubeContext }}
+`)
+
+	expectedValues := `envName: production
+envContext: myCtx
+releaseName: myrelease
+releaseContext: 
+`
+
+	testFs := testhelper.NewTestFs(map[string]string{
+		valuesFile: string(valuesContent),
+	})
+	testFs.Cwd = "/example/path/to"
+
+	r := remote.NewRemote(logger, testFs.Cwd, testFs.ToFileSystem())
+	state, err := NewCreator(logger, testFs.ToFileSystem(), nil, nil, "", r, false, "").
+		ParseAndLoad(yamlContent, filepath.Dir(yamlFile), yamlFile, "production", true, nil, nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	release := state.Releases[0]
+
+	state.ApplyOverrides(&release)
+
+	actualValuesData, err := state.RenderReleaseValuesFileToBytes(&release, valuesFile)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	actualValues := string(actualValuesData)
+
+	if !reflect.DeepEqual(expectedValues, actualValues) {
+		t.Errorf("unexpected values: expected=%v, actual=%v", expectedValues, actualValues)
+	}
+}