Merge pull request helm#79 from Sajfer/preapply

Add preapply hook

docs/index.md

@@ -1183,6 +1183,7 @@ Once `events` are triggered, associated `hooks` are executed, by running the `co
 Currently supported `events` are:
 
 - `prepare`
+- `preapply`
 - `presync`
 - `preuninstall`
 - `postuninstall`
@@ -1192,9 +1193,12 @@ Currently supported `events` are:
 Hooks associated to `prepare` events are triggered after each release in your helmfile is loaded from YAML, before execution.
 `prepare` hooks are triggered on the release as long as it is not excluded by the helmfile selector(e.g. `helmfile -l key=value`).
 
-Hooks associated to `presync` events are triggered before each release is applied to the remote cluster.
+Hooks associated to `presync` events are triggered before each release is installed or upgraded on the remote cluster.
 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.
+
 `preuninstall` hooks are triggered immediately before a release is uninstalled as part of `helmfile apply`, `helmfile sync`, `helmfile delete`, and `helmfile destroy`.
 
 `postuninstall` hooks are triggered immediately after successful uninstall of a release while running `helmfile apply`, `helmfile sync`, `helmfile delete`, `helmfile destroy`.

go.mod

@@ -29,12 +29,14 @@ require (
 	github.com/variantdev/vals v0.18.0
 	go.uber.org/multierr v1.6.0
 	go.uber.org/zap v1.23.0
+	golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
 	gopkg.in/yaml.v2 v2.4.0
 	gotest.tools v2.2.0+incompatible
 	helm.sh/helm/v3 v3.8.1
 	k8s.io/apimachinery v0.24.4
+	k8s.io/utils v0.0.0-20220210201930-3a6ce19ff2f9
 )
 
 require (
@@ -194,7 +196,6 @@ require (
 	k8s.io/client-go v0.23.4 // indirect
 	k8s.io/klog/v2 v2.60.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20220328201542-3ee0da9b0b42 // indirect
-	k8s.io/utils v0.0.0-20220210201930-3a6ce19ff2f9 // indirect
 	oras.land/oras-go v1.1.0 // indirect
 	sigs.k8s.io/kustomize/api v0.10.1 // indirect
 	sigs.k8s.io/kustomize/kyaml v0.13.0 // indirect

go.sum

@@ -1373,6 +1373,8 @@ golang.org/x/exp v0.0.0-20191227195350-da58074b4299/go.mod h1:2RIsYlXP63K8oxa1u0
 golang.org/x/exp v0.0.0-20200119233911-0405dc783f0a/go.mod h1:2RIsYlXP63K8oxa1u096TMicItID8zy7Y6sNkU49FU4=
 golang.org/x/exp v0.0.0-20200207192155-f17229e696bd/go.mod h1:J/WKrq2StrnmMY6+EHIKF9dgMWnmCNThgcyBT1FY9mM=
 golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6/go.mod h1:3jZMyOhIsHpP37uCMkUooju7aAi5cS1Q23tOzKc+0MU=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561 h1:MDc5xs78ZrZr3HMQugiXOAkSZtfTpbJLDr/lwfgO53E=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=

pkg/app/app.go

@@ -790,7 +790,7 @@ func (a *App) visitStates(fileOrDir string, defOpts LoadOpts, converge func(*sta
 		go func() {
 			sig := <-sigs
 
-			errs := []error{fmt.Errorf("Received [%s] to shutdown ", sig)}
+			errs := []error{fmt.Errorf("received [%s] to shutdown ", sig)}
 			_ = context{app: a, st: st, retainValues: defOpts.RetainValuesFiles}.clean(errs)
 			// See http://tldp.org/LDP/abs/html/exitcodes.html
 			switch sig {
@@ -1342,7 +1342,7 @@ Do you really want to apply?
 		a.Logger.Debug(*infoMsg)
 	}
 
-	applyErrs := []error{}
+	var applyErrs []error
 
 	affectedReleases := state.AffectedReleases{}
 
@@ -1355,15 +1355,27 @@ Do you really want to apply?
 		// We deleted releases by traversing the DAG in reverse order
 		if len(releasesToBeDeleted) > 0 {
 			_, deletionErrs := withDAG(st, helm, a.Logger, state.PlanOptions{Reverse: true, SelectedReleases: toDelete, SkipNeeds: true}, a.WrapWithoutSelector(func(subst *state.HelmState, helm helmexec.Interface) []error {
-				var rs []state.ReleaseSpec
+				var (
+					rs             []state.ReleaseSpec
+					preapplyErrors []error
+				)
 
 				for _, r := range subst.Releases {
 					release := r
 					if r2, ok := releasesToBeDeleted[state.ReleaseToID(&release)]; ok {
+						if _, err := st.TriggerPreapplyEvent(&r2, "apply"); err != nil {
+							preapplyErrors = append(applyErrs, err)
+							continue
+						}
+
 						rs = append(rs, r2)
 					}
 				}
 
+				if len(preapplyErrors) > 0 {
+					return preapplyErrors
+				}
+
 				subst.Releases = rs
 
 				return subst.DeleteReleasesForSync(&affectedReleases, helm, c.Concurrency())
@@ -1377,15 +1389,27 @@ Do you really want to apply?
 		// We upgrade releases by traversing the DAG
 		if len(releasesToBeUpdated) > 0 {
 			_, updateErrs := withDAG(st, helm, a.Logger, state.PlanOptions{SelectedReleases: toUpdate, Reverse: false, SkipNeeds: true, IncludeTransitiveNeeds: c.IncludeTransitiveNeeds()}, a.WrapWithoutSelector(func(subst *state.HelmState, helm helmexec.Interface) []error {
-				var rs []state.ReleaseSpec
+				var (
+					rs             []state.ReleaseSpec
+					preapplyErrors []error
+				)
 
 				for _, r := range subst.Releases {
 					release := r
 					if r2, ok := releasesToBeUpdated[state.ReleaseToID(&release)]; ok {
+						if _, err := st.TriggerPreapplyEvent(&r2, "apply"); err != nil {
+							preapplyErrors = append(applyErrs, err)
+							continue
+						}
+
 						rs = append(rs, r2)
 					}
 				}
 
+				if len(preapplyErrors) > 0 {
+					return preapplyErrors
+				}
+
 				subst.Releases = rs
 
 				syncOpts := state.SyncOpts{