Refactoring reconciliation loop into control & logic, adding initial (incomplete) tests

Signed-off-by: Danny Kopping <danny@coder.com>

enterprise/coderd/prebuilds/controller_test.go

@@ -0,0 +1,130 @@
+package prebuilds
+
+import (
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/v2/coderd/database"
+)
+
+var (
+	templateID        = uuid.New()
+	templateVersionID = uuid.New()
+	presetID          = uuid.New()
+	preset2ID         = uuid.New()
+	prebuildID        = uuid.New()
+)
+
+func TestReconciliationActions(t *testing.T) {
+	cases := map[string]struct {
+		preset     database.GetTemplatePresetsWithPrebuildsRow // TODO: make own structs; reusing these types is lame
+		running    []database.GetRunningPrebuildsRow
+		inProgress []database.GetPrebuildsInProgressRow
+		expected   reconciliationActions
+	}{
+		// New template version created which adds a new preset with prebuilds configured.
+		"CreateNetNew": {
+			preset: preset(true, 1),
+			expected: reconciliationActions{
+				desired: 1,
+				create:  1,
+			},
+		},
+		// New template version created, making an existing preset and its prebuilds outdated.
+		"DeleteOutdated": {
+			preset: preset(false, 1),
+			running: []database.GetRunningPrebuildsRow{
+				{
+					WorkspaceID:       prebuildID,
+					TemplateID:        templateID,
+					TemplateVersionID: templateVersionID,
+					CurrentPresetID:   uuid.NullUUID{UUID: presetID, Valid: true},
+					DesiredPresetID:   uuid.NullUUID{UUID: uuid.New(), Valid: true},
+					Ready:             true,
+				},
+			},
+			expected: reconciliationActions{
+				outdated:  1,
+				deleteIDs: []uuid.UUID{prebuildID},
+			},
+		},
+		// Somehow an additional prebuild is running, delete it.
+		// This can happen if an operator messes with a prebuild's state (stop, start).
+		"DeleteOldestExtraneous": {
+			preset: preset(true, 1),
+			running: []database.GetRunningPrebuildsRow{
+				{
+					WorkspaceID:       prebuildID,
+					TemplateID:        templateID,
+					TemplateVersionID: templateVersionID,
+					CurrentPresetID:   uuid.NullUUID{UUID: presetID, Valid: true},
+					DesiredPresetID:   uuid.NullUUID{UUID: uuid.New(), Valid: true},
+					CreatedAt:         time.Now().Add(-time.Hour),
+				},
+				{
+					WorkspaceID:       uuid.New(),
+					TemplateID:        templateID,
+					TemplateVersionID: templateVersionID,
+					CurrentPresetID:   uuid.NullUUID{UUID: presetID, Valid: true},
+					DesiredPresetID:   uuid.NullUUID{UUID: uuid.New(), Valid: true},
+					CreatedAt:         time.Now(),
+				},
+			},
+			expected: reconciliationActions{
+				desired:    1,
+				extraneous: 1,
+				actual:     2,
+				deleteIDs:  []uuid.UUID{prebuildID},
+			},
+		},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			ps := presetState{
+				preset:     tc.preset,
+				running:    tc.running,
+				inProgress: tc.inProgress,
+			}
+
+			actions, err := ps.calculateActions()
+			require.NoError(t, err, "could not calculate reconciliation actions")
+
+			validateActions(t, tc.expected, *actions)
+		})
+	}
+}
+
+func preset(active bool, instances int32) database.GetTemplatePresetsWithPrebuildsRow {
+	return database.GetTemplatePresetsWithPrebuildsRow{
+		TemplateID:         templateID,
+		TemplateVersionID:  templateVersionID,
+		UsingActiveVersion: active,
+		PresetID:           presetID,
+		Name:               "bob",
+		DesiredInstances:   instances,
+		Deleted:            false,
+		Deprecated:         false,
+	}
+}
+
+// validateActions is a convenience func to make tests more readable; it exploits the fact that the default states for
+// prebuilds align with zero values.
+func validateActions(t *testing.T, expected, actual reconciliationActions) bool {
+	return assert.EqualValuesf(t, expected.deleteIDs, actual.deleteIDs, "'deleteIDs' did not match expectation") &&
+		assert.EqualValuesf(t, expected.create, actual.create, "'create' did not match expectation") &&
+		assert.EqualValuesf(t, expected.desired, actual.desired, "'desired' did not match expectation") &&
+		assert.EqualValuesf(t, expected.actual, actual.actual, "'actual' did not match expectation") &&
+		assert.EqualValuesf(t, expected.eligible, actual.eligible, "'eligible' did not match expectation") &&
+		assert.EqualValuesf(t, expected.extraneous, actual.extraneous, "'extraneous' did not match expectation") &&
+		assert.EqualValuesf(t, expected.outdated, actual.outdated, "'outdated' did not match expectation") &&
+		assert.EqualValuesf(t, expected.starting, actual.starting, "'starting' did not match expectation") &&
+		assert.EqualValuesf(t, expected.stopping, actual.stopping, "'stopping' did not match expectation") &&
+		assert.EqualValuesf(t, expected.deleting, actual.deleting, "'deleting' did not match expectation")
+}