Merge pull request juju#18460 from gfouillet/v4/dqlite/resources/stat…

…e-6479-manage-rows

juju#18460

Implements function to delete resources.

Include service and state layer.

* DeleteUnitResource removes the links between a unit and its linked resources
* DeleteApplicationResource removes all resources from an application, providing their are not linked to any unit or stored data.

> [!NOTE]
> Adding resources will be done in another PR, directly in the CreateApplication transaction

<!-- Why this change is needed and what it does. -->

## Checklist

<!-- If an item is not applicable, use `~strikethrough~`. -->

- [x] Code style: imports ordered, good names, simple structure, etc
- [x] Comments saying why design decisions were made
- [x] Go unit tests, with comments saying what you're testing
~- [ ] [Integration tests](https://github.com/juju/juju/tree/main/tests), with comments saying what you're testing~
~- [ ] [doc.go](https://discourse.charmhub.io/t/readme-in-packages/451) added or updated in changed packages~

## QA steps

None. Unit test should pass and cover usecases.

## Documentation changes

None

## Links

**Jira card:** JUJU-[6479](https://warthogs.atlassian.net/browse/JUJU-6479)

api/package_test.go

@@ -60,6 +60,7 @@ func (*ImportSuite) TestImports(c *gc.C) {
 		"internal/charm/assumes",
 		"internal/charm/hooks",
 		"internal/charm/resource",
+		"internal/errors",
 		"internal/featureflag",
 		"internal/http",
 		"internal/logger",

core/migration/package_test.go

@@ -31,6 +31,7 @@ func (*ImportTest) TestImports(c *gc.C) {
 		"core/network",
 		"core/resource",
 		"internal/charm/resource",
+		"internal/errors",
 		"internal/logger",
 		"internal/uuid",
 	})

core/resource/state.go

@@ -0,0 +1,46 @@
+// Copyright 2024 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package resource
+
+import (
+	"github.com/juju/juju/internal/errors"
+)
+
+// These are the valid resource states.
+const (
+	// StateAvailable represents a resource which will be used by any units at
+	// this point in time
+	StateAvailable State = "available"
+
+	// StatePotential indicates there is a different revision of the resource
+	// available in a repository. Used to let users know a resource can be
+	// upgraded.
+	StatePotential State = "potential"
+)
+
+// State identifies the resource state in an application
+type State string
+
+// ParseState converts the provided string into an State.
+// If it is not a known state then an error is returned.
+func ParseState(value string) (State, error) {
+	state := State(value)
+	return state, state.Validate()
+}
+
+// String returns the printable representation of the state.
+func (o State) String() string {
+	return string(o)
+}
+
+// Validate ensures that the state is correct.
+func (o State) Validate() error {
+	if _, ok := map[State]bool{
+		StateAvailable: true,
+		StatePotential: true,
+	}[o]; !ok {
+		return errors.Errorf("state %q invalid", o)
+	}
+	return nil
+}

core/resource/state_test.go

@@ -0,0 +1,54 @@
+// Copyright 2024 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package resource
+
+import (
+	"github.com/juju/testing"
+	jc "github.com/juju/testing/checkers"
+	gc "gopkg.in/check.v1"
+)
+
+type StateSuite struct {
+	testing.IsolationSuite
+}
+
+var _ = gc.Suite(&StateSuite{})
+
+func (StateSuite) TestParseStateKnown(c *gc.C) {
+	recognized := map[string]State{
+		"potential": StatePotential,
+		"available": StateAvailable,
+	}
+	for value, expected := range recognized {
+		state, err := ParseState(value)
+
+		c.Check(err, jc.ErrorIsNil)
+		c.Check(state, gc.Equals, expected)
+	}
+}
+
+func (StateSuite) TestParseStateUnknown(c *gc.C) {
+	_, err := ParseState("<invalid>")
+
+	c.Check(err, gc.ErrorMatches, `.*state "<invalid>" invalid.*`)
+}
+
+func (StateSuite) TestValidateKnown(c *gc.C) {
+	recognized := []State{
+		StatePotential,
+		StateAvailable,
+	}
+	for _, state := range recognized {
+		err := state.Validate()
+
+		c.Check(err, jc.ErrorIsNil)
+	}
+}
+
+func (StateSuite) TestValidateUnknown(c *gc.C) {
+	var state State
+	err := state.Validate()
+
+	c.Check(err, gc.ErrorMatches, `.*state "" invalid.*`)
+}

core/watcher/eventsource/package_test.go

@@ -45,6 +45,7 @@ func (*ImportTest) TestImports(c *gc.C) {
 		"core/status",
 		"core/watcher",
 		"internal/charm/resource",
+		"internal/errors",
 		"internal/logger",
 		"internal/uuid",
 	})

core/watcher/package_test.go

@@ -33,6 +33,7 @@ func (s *ImportTest) TestImports(c *gc.C) {
 		"core/secrets",
 		"core/status",
 		"internal/charm/resource",
+		"internal/errors",
 		"internal/logger",
 		"internal/uuid",
 	})

domain/resource/errors/errors.go

@@ -3,9 +3,15 @@
 
 package errors
 
-import "github.com/juju/juju/internal/errors"
+import (
+	"github.com/juju/juju/internal/errors"
+)
 
 const (
+	// ApplicationIDNotValid describes an error when the application ID is
+	// not valid.
+	ApplicationIDNotValid = errors.ConstError("application ID not valid")
+
 	// ApplicationNotFound describes an error that occurs when the application
 	// being operated on does not exist.
 	ApplicationNotFound = errors.ConstError("application not found")
@@ -29,4 +35,17 @@ const (
 	// UnitNotFound describes an error that occurs when the unit being operated on
 	// does not exist.
 	UnitNotFound = errors.ConstError("unit not found")
+
+	// UnitUUIDNotValid describes an error when the unit UUID is
+	// not valid.
+	UnitUUIDNotValid = errors.ConstError("unit UUID not valid")
+
+	// ResourceStateNotValid describes an error where the resource state is not
+	// valid.
+	ResourceStateNotValid = errors.ConstError("resource state not valid")
+
+	// InvalidCleanUpState describes an error where the application state is
+	// during cleanup. It means that application dependencies are deleted in
+	// an incorrect order.
+	InvalidCleanUpState = errors.ConstError("invalid cleanup state")
 )