Fix preapply hooks are not called on no diff when run apply subcommand (#522)

* Fix presync hooks are not called on no diff when run apply subcommand

Signed-off-by: xiaomudk <xiaomudk@gmail.com>

* Update docs/index.md

Co-authored-by: Yusuke Kuoka <ykuoka@gmail.com>
Signed-off-by: xiaomudk <xiaomudk@gmail.com>

Signed-off-by: xiaomudk <xiaomudk@gmail.com>
Co-authored-by: Yusuke Kuoka <ykuoka@gmail.com>

docs/index.md

@@ -1240,7 +1240,7 @@ Hooks associated to `presync` events are triggered before each release is instal
 This is the ideal event to execute any commands that may mutate the cluster state as it will not be run for read-only operations like `lint`, `diff` or `template`.
 
 `preapply` hooks are triggered before a release is uninstalled, installed, or upgraded as part of `helmfile apply`.
-This is the ideal event to hook into when you are going to use `helmfile apply` for every kind of change, and you want the hook to be called only when any kind of change is being made.
+This is the ideal event to hook into when you are going to use `helmfile apply` for every kind of change and you want the hook to be triggered regardless of whether the releases have changed or not. Be sure to make each `preapply` hook command idempotent. Otherwise, rerunning helmfile-apply on a transient failure may end up either breaking your cluster, or the hook that runs for the second time will never succeed.
 
 `preuninstall` hooks are triggered immediately before a release is uninstalled as part of `helmfile apply`, `helmfile sync`, `helmfile delete`, and `helmfile destroy`.
 

pkg/app/app.go

@@ -1354,30 +1354,20 @@ func (a *App) apply(r *Run, c ApplyConfigProvider) (bool, bool, []error) {
 		}
 	}
 
-	for id := range releasesWithNoChange {
-		r := releasesWithNoChange[id]
-		if _, err := st.TriggerCleanupEvent(&r, "apply"); err != nil {
-			a.Logger.Warnf("warn: %v\n", err)
-		}
-	}
-
-	if releasesToBeDeleted == nil && releasesToBeUpdated == nil {
-		if infoMsg != nil {
-			logger := c.Logger()
-			logger.Infof("")
-			logger.Infof(*infoMsg)
-		}
-		return true, false, nil
+	infoMsgStr := ""
+	if infoMsg != nil {
+		infoMsgStr = *infoMsg
 	}
 
 	confMsg := fmt.Sprintf(`%s
 Do you really want to apply?
   Helmfile will apply all your changes, as shown above.
 
-`, *infoMsg)
+`, infoMsgStr)
+
 	interactive := c.Interactive()
-	if !interactive {
-		a.Logger.Debug(*infoMsg)
+	if !interactive && infoMsgStr != "" {
+		a.Logger.Debug(infoMsgStr)
 	}
 
 	var applyErrs []error
@@ -1457,6 +1447,17 @@ Do you really want to apply?
 	}
 
 	affectedReleases.DisplayAffectedReleases(c.Logger())
+
+	for id := range releasesWithNoChange {
+		r := releasesWithNoChange[id]
+		if _, err := st.TriggerCleanupEvent(&r, "apply"); err != nil {
+			a.Logger.Warnf("warn: %v\n", err)
+		}
+	}
+	if releasesToBeDeleted == nil && releasesToBeUpdated == nil {
+		return true, false, nil
+	}
+
 	return true, true, applyErrs
 }
 

pkg/app/testdata/testapply/noop/log

@@ -34,4 +34,11 @@ second-pass rendering result of "helmfile.yaml.part.0":
 merged environment: &{default map[] map[]}
 2 release(s) found in helmfile.yaml
 
+invoking preapply hooks for 2 groups of releases in this order:
+GROUP RELEASES
+1     default//foo
+2     default//bar
+
+invoking preapply hooks for releases in group 1/2: default//foo
+invoking preapply hooks for releases in group 2/2: default//bar
 changing working directory back to "/path/to"

pkg/app/testdata/testapply_hooks/hooks_for_no-diff_release/log

@@ -2,5 +2,8 @@
 hook[prepare] logs | foo
 hook[prepare] logs | 
 
+hook[preapply] logs | foo
+hook[preapply] logs | 
+
 hook[cleanup] logs | foo
 hook[cleanup] logs |