feat: controller runtime implementation

This enhances Resource and State implementation, and build initial
Controller and Controller Runtime implementation. Code is reasonably
covered with tunit-tests.

Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>

.golangci.yml

@@ -1,6 +1,6 @@
 # THIS FILE WAS AUTOMATICALLY GENERATED, PLEASE DO NOT EDIT.
 #
-# Generated on 2020-08-28T20:43:11Z by kres 292ed36-dirty.
+# Generated on 2020-12-30T20:27:21Z by kres latest.
 
 
 # options for analysis running
@@ -125,6 +125,9 @@ linters:
     - gomnd
     - goerr113
     - nestif
+    - wrapcheck
+    - paralleltest
+    - exhaustivestruct
   disable-all: false
   fast: false
 

Dockerfile

@@ -1,8 +1,8 @@
-# syntax = docker/dockerfile-upstream:1.1.7-experimental
+# syntax = docker/dockerfile-upstream:1.2.0-labs
 
 # THIS FILE WAS AUTOMATICALLY GENERATED, PLEASE DO NOT EDIT.
 #
-# Generated on 2020-08-28T20:50:10Z by kres 292ed36-dirty.
+# Generated on 2020-12-30T20:27:21Z by kres latest.
 
 ARG TOOLCHAIN
 
@@ -24,7 +24,7 @@ FROM toolchain AS tools
 ENV GO111MODULE on
 ENV CGO_ENABLED 0
 ENV GOPATH /go
-RUN curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b /bin v1.30.0
+RUN curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b /bin v1.33.0
 ARG GOFUMPT_VERSION
 RUN cd $(mktemp -d) \
 	&& go mod init tmp \

cmd/directory-fun/main.go

@@ -13,13 +13,13 @@ import (
 
 	"github.com/talos-systems/os-runtime/pkg/resource"
 	"github.com/talos-systems/os-runtime/pkg/state"
-	"github.com/talos-systems/os-runtime/pkg/state/impl/local"
+	"github.com/talos-systems/os-runtime/pkg/state/impl/inmem"
 )
 
 // DirectoryTask implements simple process attached to the state.
 //
 // DirectoryTask attempts to create path when the parent path got created.
-// DirectoryTask watches for parent to be torn down, starts tear down, waits for children
+// DirectoryTask watches for parent to be torn down, starts tear down process, waits for children
 // to be destroyed, and removes the path.
 //
 // DirectoryTask is a model of task in some OS sequencer.
@@ -34,7 +34,9 @@ func DirectoryTask(world state.State, path string) {
 		err    error
 	)
 
-	if parent, err = world.WatchFor(ctx, resource.NewMetadata(defaultNs, PathResourceType, base, resource.VersionUndefined), state.WithEventTypes(state.Created, state.Updated)); err != nil {
+	if parent, err = world.WatchFor(ctx,
+		resource.NewMetadata(defaultNs, PathResourceType, base, resource.VersionUndefined),
+		state.WithEventTypes(state.Created, state.Updated)); err != nil {
 		log.Fatal(err)
 	}
 
@@ -52,38 +54,39 @@ func DirectoryTask(world state.State, path string) {
 
 	log.Printf("%q: created %q", path, path)
 
-	if parent, err = world.UpdateWithConflicts(ctx, parent, func(r resource.Resource) error {
-		r.(*PathResource).AddDependent(self)
+	if err = world.AddFinalizer(ctx, parent.Metadata(), self.String()); err != nil {
+		log.Fatal(err)
+	}
 
-		return nil
-	}); err != nil {
+	parent, err = world.Get(ctx, parent.Metadata())
+	if err != nil {
 		log.Fatal(err)
 	}
 
-	log.Printf("%q: %q.dependents = %q", path, parent.Metadata().ID(), parent.(*PathResource).spec.dependents)
+	log.Printf("%q: parent %q finalizers are %q", path, base, parent.Metadata().Finalizers())
 
 	// doing something useful here <>
 
 	log.Printf("%q: watching for teardown %q", path, base)
 
-	if parent, err = world.WatchFor(ctx, resource.NewMetadata(defaultNs, PathResourceType, base, resource.VersionUndefined), state.WithEventTypes(state.Destroyed, state.Torndown)); err != nil {
+	if parent, err = world.WatchFor(ctx,
+		parent.Metadata(),
+		state.WithEventTypes(state.Created, state.Updated),
+		state.WithPhases(resource.PhaseTearingDown)); err != nil {
 		log.Fatal(err)
 	}
 
 	log.Printf("%q: teardown self", path)
 
-	if err = world.Teardown(ctx, self.Metadata()); err != nil {
+	if _, err = world.Teardown(ctx, self.Metadata()); err != nil {
 		log.Fatal(err)
 	}
 
 	log.Printf("%q: watching for dependents to vanish %q", path, path)
 
 	if _, err = world.WatchFor(ctx,
-		resource.NewMetadata(defaultNs, PathResourceType, path, resource.VersionUndefined),
-		state.WithEventTypes(state.Created, state.Updated, state.Torndown),
-		state.WithCondition(func(r resource.Resource) (bool, error) {
-			return len(r.(*PathResource).spec.dependents) == 0, nil
-		})); err != nil {
+		self.Metadata(),
+		state.WithFinalizerEmpty()); err != nil {
 		log.Fatal(err)
 	}
 
@@ -93,14 +96,17 @@ func DirectoryTask(world state.State, path string) {
 		log.Fatal(err)
 	}
 
-	if _, err = world.UpdateWithConflicts(ctx, parent, func(r resource.Resource) error {
-		r.(*PathResource).DropDependent(self)
+	if err = world.RemoveFinalizer(ctx, parent.Metadata(), self.String()); err != nil {
+		log.Fatal(err)
+	}
 
-		return nil
-	}); err != nil {
+	parent, err = world.Get(ctx, parent.Metadata())
+	if err != nil {
 		log.Fatal(err)
 	}
 
+	log.Printf("%q: parent %q finalizers are %q", path, base, parent.Metadata().Finalizers())
+
 	if err = world.Destroy(ctx, self.Metadata()); err != nil {
 		log.Fatal(err)
 	}
@@ -110,7 +116,7 @@ const defaultNs = "default"
 
 func main() {
 	ctx := context.Background()
-	world := state.WrapCore(local.NewState(defaultNs))
+	world := state.WrapCore(inmem.NewState(defaultNs))
 
 	root := NewPathResource(defaultNs, ".")
 	if err := world.Create(ctx, root); err != nil {
@@ -137,9 +143,22 @@ func main() {
 
 	time.Sleep(2 * time.Second)
 
-	if err := world.Teardown(ctx, root.Metadata()); err != nil {
+	if _, err := world.Teardown(ctx, root.Metadata()); err != nil {
 		log.Fatal(err)
 	}
 
-	time.Sleep(10 * time.Second)
+	if _, err := world.WatchFor(ctx,
+		root.Metadata(),
+		state.WithFinalizerEmpty()); err != nil {
+		log.Fatal(err)
+	}
+
+	rootRes, err := world.Get(ctx, root.Metadata())
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err := world.Destroy(ctx, rootRes.Metadata()); err != nil {
+		log.Fatal(err)
+	}
 }

cmd/directory-fun/path.go

@@ -13,17 +13,12 @@ import (
 
 const PathResourceType = resource.Type("os/path")
 
-type pathResourceSpec struct {
-	dependents []string
-}
-
 // PathResource represents a path in the filesystem.
 //
 // Resource ID is the path, and dependents are all the immediate
 // children on the path.
 type PathResource struct {
-	md   resource.Metadata
-	spec pathResourceSpec
+	md resource.Metadata
 }
 
 func NewPathResource(ns resource.Namespace, path string) *PathResource {
@@ -35,40 +30,20 @@ func NewPathResource(ns resource.Namespace, path string) *PathResource {
 	return r
 }
 
-func (path *PathResource) Metadata() resource.Metadata {
-	return path.md
+func (path *PathResource) Metadata() *resource.Metadata {
+	return &path.md
 }
 
 func (path *PathResource) Spec() interface{} {
-	return path.spec
+	return nil
 }
 
 func (path *PathResource) String() string {
 	return fmt.Sprintf("PathResource(%q)", path.md.ID())
 }
 
-func (path *PathResource) Copy() resource.Resource {
+func (path *PathResource) DeepCopy() resource.Resource {
 	return &PathResource{
 		md: path.md,
-		spec: pathResourceSpec{
-			dependents: append([]string(nil), path.spec.dependents...),
-		},
 	}
 }
-
-func (path *PathResource) AddDependent(dependent *PathResource) {
-	path.spec.dependents = append(path.spec.dependents, dependent.md.ID())
-	path.md.BumpVersion()
-}
-
-func (path *PathResource) DropDependent(dependent *PathResource) {
-	for i, p := range path.spec.dependents {
-		if p == dependent.md.ID() {
-			path.spec.dependents = append(path.spec.dependents[:i], path.spec.dependents[i+1:]...)
-
-			break
-		}
-	}
-
-	path.md.BumpVersion()
-}

go.mod

@@ -2,4 +2,13 @@ module github.com/talos-systems/os-runtime
 
 go 1.14
 
-require github.com/stretchr/testify v1.6.1
+require (
+	github.com/AlekSi/pointer v1.1.0
+	github.com/hashicorp/go-memdb v1.3.0
+	github.com/hashicorp/go-multierror v1.1.0
+	github.com/stretchr/testify v1.6.1
+	github.com/talos-systems/go-retry v0.2.0
+	go.uber.org/goleak v1.1.10
+	golang.org/x/sync v0.0.0-20190423024810-112230192c58
+	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c
+)

go.sum

@@ -1,11 +1,52 @@
+github.com/AlekSi/pointer v1.1.0 h1:SSDMPcXD9jSl8FPy9cRzoRaMJtm9g9ggGTxecRUbQoI=
+github.com/AlekSi/pointer v1.1.0/go.mod h1:y7BvfRI3wXPWKXEBhU71nbnIEEZX0QTSB2Bj48UJIZE=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
+github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
+github.com/hashicorp/go-immutable-radix v1.3.0 h1:8exGP7ego3OmkfksihtSouGMZ+hQrhxx+FVELeXpVPE=
+github.com/hashicorp/go-immutable-radix v1.3.0/go.mod h1:0y9vanUI8NX6FsYoO3zeMjhV/C5i9g4Q3DwcSNZ4P60=
+github.com/hashicorp/go-memdb v1.3.0 h1:xdXq34gBOMEloa9rlGStLxmfX/dyIK8htOv36dQUwHU=
+github.com/hashicorp/go-memdb v1.3.0/go.mod h1:Mluclgwib3R93Hk5fxEfiRhB+6Dar64wWh71LpNSe3g=
+github.com/hashicorp/go-multierror v1.1.0 h1:B9UzwGQJehnUY1yNrnwREHc3fGbC2xefo8g4TbElacI=
+github.com/hashicorp/go-multierror v1.1.0/go.mod h1:spPvp8C1qA32ftKqdAHm4hHTbPw+vmowP0z+KUhOZdA=
+github.com/hashicorp/go-uuid v1.0.0 h1:RS8zrF7PhGwyNPOtxSClXXj9HA8feRnJzgnI1RJCSnM=
+github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
+github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
+github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
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+github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
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 github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
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+golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
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 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
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+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
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pkg/controller/controller.go

@@ -0,0 +1,21 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Package controller defines common interfaces to be implemented by the controllers and controller runtime.
+package controller
+
+import (
+	"context"
+	"log"
+
+	"github.com/talos-systems/os-runtime/pkg/resource"
+)
+
+// Controller interface should be implemented by Controllers.
+type Controller interface {
+	Name() string
+	ManagedResources() (resource.Namespace, resource.Type)
+
+	Run(context.Context, Runtime, *log.Logger) error
+}

pkg/controller/runtime.go

@@ -0,0 +1,69 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package controller
+
+import (
+	"context"
+
+	"github.com/talos-systems/os-runtime/pkg/resource"
+	"github.com/talos-systems/os-runtime/pkg/state"
+)
+
+// ReconcileEvent is a signal for controller to reconcile its resources.
+type ReconcileEvent struct{}
+
+// Runtime interface as presented to the controller.
+type Runtime interface {
+	EventCh() <-chan ReconcileEvent
+	QueueReconcile()
+
+	UpdateDependencies([]Dependency) error
+
+	Reader
+	Writer
+}
+
+// DependencyKind for dependencies.
+type DependencyKind = int
+
+// Dependency kinds.
+const (
+	DependencyWeak int = iota
+	DependencyHard
+)
+
+// Dependency of controller on some resource(s).
+//
+// Each controller might have multiple dependencies, it might depend on
+// all the objects of some type under namespace, or on specific object by ID.
+//
+// Dependency might be either Weak or Hard. Any kind of dependency triggers
+// cascading reconcile on changes, hard dependencies in addition block deletion of
+// parent object until all the dependencies are torn down.
+type Dependency struct {
+	Namespace resource.Namespace
+	Type      resource.Type
+	ID        *resource.ID
+	Kind      DependencyKind
+}
+
+// Reader provides read-only access to the state.
+type Reader interface {
+	Get(context.Context, resource.Pointer) (resource.Resource, error)
+	List(context.Context, resource.Kind) (resource.List, error)
+	WatchFor(context.Context, resource.Pointer, ...state.WatchForConditionFunc) (resource.Resource, error)
+}
+
+// Writer provides write access to the state.
+//
+// Only managed objects can be written to by the controller.
+type Writer interface {
+	Update(context.Context, resource.Resource, func(resource.Resource) error) error
+	Teardown(context.Context, resource.Pointer) (bool, error)
+	Destroy(context.Context, resource.Pointer) error
+
+	AddFinalizer(context.Context, resource.Pointer, ...resource.Finalizer) error
+	RemoveFinalizer(context.Context, resource.Pointer, ...resource.Finalizer) error
+}