feat: `helmfiles: <ordered glob patterns of helmfiles>` configuration (#266)

Resolves #247

README.md

@@ -371,6 +371,76 @@ proxy:
   scheme: {{ env "SCHEME" | default "https" }}
 ```
 
+## Separating helmfile.yaml into multiple independent files
+
+Once your `helmfile.yaml` got to contain too many releases,
+split it into multiple yaml files.
+
+Recommended granularity of helmfile.yaml files is "per microservice" or "per team".
+And there are two ways to organize your files.
+
+- Single directory
+- Glob patterns
+
+### Single directory
+
+`helmfile -f path/to/directory` loads and runs all the yaml files under the specified directory, each file as an independent helmfile.yaml.
+The default helmfile directory is `helmfile.d`, that is,
+in case helmfile is unable to locate `helmfile.yaml`, it tries to locate `helmfile.d/*.yaml`.
+
+All the yaml files under the specified directory are processed in the alphabetical order. For example, you can use a `<two digit number>-<microservice>.yaml` naming convention to control the sync order.
+
+- `helmfile.d`/
+  - `00-database.yaml`
+  - `00-backend.yaml`
+  - `01-frontend.yaml`
+
+### Glob patterns
+
+In case you want more control over how multiple `helmfile.yaml` files are organized, use `helmfiles:` configuration key in the `helmfile.yaml`:
+
+Suppose you have multiple microservices organized in a Git reposistory that looks like:
+
+- `myteam/` (sometimes it is equivalent to a k8s ns, that is `kube-system` for `clusterops` team)
+  - `apps/`
+    - `filebeat/`
+      - `helmfile.yaml` (no `charts/` exists, because it depends on the stable/filebeat chart hosted on the official helm charts repository)
+      - `README.md` (each app managed by my team has a dedicated README maintained by the owners of the app)
+    - `metricbeat/`
+      - `helmfile.yaml`
+      - `README.md`
+    - `elastalert-operator/`
+      - `helmfile.yaml`
+      - `README.md`
+      - `charts/`
+        - `elastalert-operator/`
+          - `<the content of the local helm chart>`
+
+The benefits of this structure is that you can run `git diff` to locate in which directory=microservice a git commit has changes.
+It allows your CI system to run a workflow for the changed microservice only.
+
+A downside of this is that you don't have an obvious way to sync all microservices at once. That is, you have to run:
+
+```bash
+for d in apps/*; do helmfile -f $d diff; if [ $? -eq 2 ]; then helmfile -f $d sync; fi; done
+```
+
+At this point, you'll start writing a `Makefile` under `myteam/` so that `make sync-all` will do the job.
+
+It does work, but you can rely on the helmfile's feature instead.
+
+Put `myteam/helmfile.yaml` that looks like:
+
+```yaml
+helmfiles:
+- apps/*/helmfile.yaml
+```
+
+So that you can get rid of the `Makefile` and the bash snippet.
+Just run `helmfile sync` inside `myteam/`, and you are done.
+
+All the files are sorted alphabetically per group = array item inside `helmfiles:`, so that you have granular control over ordering, too.
+
 ## Using env files
 
 helmfile itself doesn't have an ability to load env files. But you can write some bash script to achieve the goal:

main.go

@@ -106,7 +106,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					args := args.GetArgs(c.String("args"), state)
 					if len(args) > 0 {
 						helm.SetExtraArgs(args...)
@@ -139,7 +139,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					args := args.GetArgs(c.String("args"), state)
 					if len(args) > 0 {
 						helm.SetExtraArgs(args...)
@@ -183,7 +183,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					return executeDiffCommand(c, state, helm, c.Bool("detailed-exitcode"))
 				})
 			},
@@ -208,7 +208,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					args := args.GetArgs(c.String("args"), state)
 					if len(args) > 0 {
 						helm.SetExtraArgs(args...)
@@ -244,7 +244,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					return executeSyncCommand(c, state, helm)
 				})
 			},
@@ -273,7 +273,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					errs := executeDiffCommand(c, state, helm, true)
 
 					// sync only when there are changes
@@ -322,7 +322,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					workers := c.Int("concurrency")
 
 					args := args.GetArgs(c.String("args"), state)
@@ -352,7 +352,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					purge := c.Bool("purge")
 
 					args := args.GetArgs(c.String("args"), state)
@@ -388,7 +388,7 @@ func main() {
 				},
 			},
 			Action: func(c *cli.Context) error {
-				return eachDesiredStateDo(c, func(state *state.HelmState, helm helmexec.Interface) []error {
+				return findAndIterateOverDesiredStatesUsingFlags(c, func(state *state.HelmState, helm helmexec.Interface) []error {
 					cleanup := c.Bool("cleanup")
 					timeout := c.Int("timeout")
 
@@ -457,14 +457,23 @@ func executeDiffCommand(c *cli.Context, state *state.HelmState, helm helmexec.In
 	return state.DiffReleases(helm, values, workers, detailedExitCode)
 }
 
-func eachDesiredStateDo(c *cli.Context, converge func(*state.HelmState, helmexec.Interface) []error) error {
-	fileOrDirPath := c.GlobalString("file")
-	desiredStateFiles, err := findDesiredStateFiles(fileOrDirPath)
+func findAndIterateOverDesiredStatesUsingFlags(c *cli.Context, converge func(*state.HelmState, helmexec.Interface) []error) error {
+	fileOrDir := c.GlobalString("file")
+	kubeContext := c.GlobalString("kube-context")
+	namespace := c.GlobalString("namespace")
+	selectors := c.GlobalStringSlice("selector")
+	logger := c.App.Metadata["logger"].(*zap.SugaredLogger)
+	return findAndIterateOverDesiredStates(fileOrDir, converge, kubeContext, namespace, selectors, logger)
+}
+
+func findAndIterateOverDesiredStates(fileOrDir string, converge func(*state.HelmState, helmexec.Interface) []error, kubeContext, namespace string, selectors []string, logger *zap.SugaredLogger) error {
+	desiredStateFiles, err := findDesiredStateFiles(fileOrDir)
 	if err != nil {
 		return err
 	}
 	allSelectorNotMatched := true
 	for _, f := range desiredStateFiles {
+		logger.Debugf("Processing %s", f)
 		yamlBuf, err := tmpl.NewFileRenderer(ioutil.ReadFile, "").RenderTemplateFileToBuffer(f)
 		if err != nil {
 			return err
@@ -472,14 +481,31 @@ func eachDesiredStateDo(c *cli.Context, converge func(*state.HelmState, helmexec
 		state, helm, noReleases, err := loadDesiredStateFromFile(
 			yamlBuf.Bytes(),
 			f,
-			c.GlobalString("kube-context"),
-			c.GlobalString("namespace"),
-			c.GlobalStringSlice("selector"),
-			c.App.Metadata["logger"].(*zap.SugaredLogger),
+			kubeContext,
+			namespace,
+			selectors,
+			logger,
 		)
 		if err != nil {
 			return err
 		}
+
+		if len(state.Helmfiles) > 0 {
+			for _, globPattern := range state.Helmfiles {
+				matches, err := filepath.Glob(globPattern)
+				if err != nil {
+					return fmt.Errorf("failed processing %s: %v", globPattern, err)
+				}
+				sort.Strings(matches)
+				for _, m := range matches {
+					if err := findAndIterateOverDesiredStates(m, converge, kubeContext, namespace, selectors, logger); err != nil {
+						return fmt.Errorf("failed processing %s: %v", globPattern, err)
+					}
+				}
+			}
+			return nil
+		}
+
 		allSelectorNotMatched = allSelectorNotMatched && noReleases
 		if noReleases {
 			continue

state/state.go

@@ -24,6 +24,7 @@ type HelmState struct {
 	BaseChartPath      string
 	FilePath           string
 	HelmDefaults       HelmSpec         `yaml:"helmDefaults"`
+	Helmfiles          []string         `yaml:"helmfiles"`
 	Context            string           `yaml:"context"`
 	DeprecatedReleases []ReleaseSpec    `yaml:"charts"`
 	Namespace          string           `yaml:"namespace"`