perf(actionsv2): execution target router (#10564)

# Which Problems Are Solved

The event execution system currently uses a projection handler that
subscribes to and processes all events for all instances. This creates a
high static cost because the system over-fetches event data, handling
many events that are not needed by most instances. This inefficiency is
also reflected in high "rows returned" metrics in the database.

# How the Problems Are Solved

Eliminate the use of a project handler. Instead, events for which
"execution targets" are defined, are directly pushed to the queue by the
eventstore. A Router is populated in the Instance object in the authz
middleware.

- By joining the execution targets to the instance, no additional
queries are needed anymore.
- As part of the instance object, execution targets are now cached as
well.
- Events are queued within the same transaction, giving transactional
guarantees on delivery.
- Uses the "insert many fast` variant of River. Multiple jobs are queued
in a single round-trip to the database.
- Fix compatibility with PostgreSQL 15

# Additional Changes

- The signing key was stored as plain-text in the river job payload in
the DB. This violated our [Secrets
Storage](https://zitadel.com/docs/concepts/architecture/secrets#secrets-storage)
principle. This change removed the field and only uses the encrypted
version of the signing key.
- Fixed the target ordering from descending to ascending.
- Some minor linter warnings on the use of `io.WriteString()`.

# Additional Context

- Introduced in https://github.com/zitadel/zitadel/pull/9249
- Closes https://github.com/zitadel/zitadel/issues/10553
- Closes https://github.com/zitadel/zitadel/issues/9832
- Closes https://github.com/zitadel/zitadel/issues/10372
- Closes https://github.com/zitadel/zitadel/issues/10492

---------

Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>
(cherry picked from commit a9ebc06c77)

internal/execution/target/router_test.go

@@ -0,0 +1,129 @@
+package target
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	eventGlobalTarget   = Target{ExecutionID: "event", TargetID: "event_global"}
+	eventGroupTarget    = Target{ExecutionID: "event/foo.*", TargetID: "event_group"}
+	eventMatchTarget    = Target{ExecutionID: "event/foo.bar", TargetID: "event_specific"}
+	functionCallTarget1 = Target{ExecutionID: "function/Call", TargetID: "function_call_1"}
+	functionCallTarget2 = Target{ExecutionID: "function/Call", TargetID: "function_call_2"}
+
+	testTargets = []Target{eventGlobalTarget, eventGroupTarget, eventMatchTarget, functionCallTarget1, functionCallTarget2}
+)
+
+func TestBinarySearchRouter_Get(t *testing.T) {
+	r := NewRouter(testTargets)
+	type args struct {
+		id string
+	}
+	tests := []struct {
+		name        string
+		args        args
+		wantTargets []Target
+		wantOk      bool
+	}{
+		{
+			name: "event global does not match exactly",
+			args: args{
+				id: "event/bar.foo",
+			},
+			wantTargets: nil,
+			wantOk:      false,
+		},
+		{
+			name: "event group does not match exactly",
+			args: args{
+				id: "event/foo.bar.baz",
+			},
+			wantTargets: nil,
+			wantOk:      false,
+		},
+		{
+			name: "event match",
+			args: args{
+				id: "event/foo.bar",
+			},
+			wantTargets: []Target{eventMatchTarget},
+			wantOk:      true,
+		},
+		{
+			name: "function match",
+			args: args{
+				id: "function/Call",
+			},
+			wantTargets: []Target{functionCallTarget1, functionCallTarget2},
+			wantOk:      true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, ok := r.Get(tt.args.id)
+			assert.Equal(t, tt.wantTargets, got)
+			assert.Equal(t, tt.wantOk, ok)
+		})
+	}
+}
+
+func TestBinarySearchRouter_GetEventBestMatch(t *testing.T) {
+	type args struct {
+		id string
+	}
+	tests := []struct {
+		name        string
+		targets     []Target
+		args        args
+		wantTargets []Target
+		wantOk      bool
+	}{
+
+		{
+			name:    "event global match",
+			targets: testTargets,
+			args: args{
+				id: "event/bar.foo",
+			},
+			wantTargets: []Target{eventGlobalTarget},
+			wantOk:      true,
+		},
+		{
+			name:    "event group match",
+			targets: testTargets[1:],
+			args: args{
+				id: "event/foo.bar.baz",
+			},
+			wantTargets: []Target{eventGroupTarget},
+			wantOk:      true,
+		},
+		{
+			name:    "event match",
+			targets: testTargets,
+			args: args{
+				id: "event/foo.bar",
+			},
+			wantTargets: []Target{eventMatchTarget},
+			wantOk:      true,
+		},
+		{
+			name:    "function match",
+			targets: testTargets,
+			args: args{
+				id: "function/Call",
+			},
+			wantTargets: []Target{functionCallTarget1, functionCallTarget2},
+			wantOk:      true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			r := NewRouter(tt.targets)
+			got, ok := r.GetEventBestMatch(tt.args.id)
+			assert.Equal(t, tt.wantTargets, got)
+			assert.Equal(t, tt.wantOk, ok)
+		})
+	}
+}