feat(tfstated): allow configuration of version history limit via environment variable

cmd/tfstated/main.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strconv"
 	"sync"
 	"time"
 
@@ -42,6 +43,14 @@ func run(
 	if err := db.SetDataEncryptionKey(dataEncryptionKey); err != nil {
 		return err
 	}
+	versionsHistoryLimit := getenv("VERSIONS_HISTORY_LIMIT")
+	if versionsHistoryLimit != "" {
+		n, err := strconv.Atoi(versionsHistoryLimit)
+		if err != nil {
+			return fmt.Errorf("failed to parse the VERSIONS_HISTORY_LIMIT environment variable: %w", err)
+		}
+		db.SetVersionsHistoryLimit(n)
+	}
 
 	mux := http.NewServeMux()
 	addRoutes(

cmd/tfstated/main_test.go

@@ -18,6 +18,7 @@ var baseURI = url.URL{
 	Path:   "/",
 	Scheme: "http",
 }
+var db *database.DB
 
 func TestMain(m *testing.M) {
 	ctx := context.Background()
@@ -27,7 +28,8 @@ func TestMain(m *testing.M) {
 		Port: "8081",
 	}
 	_ = os.Remove("./test.db")
-	db, err := database.NewDB(ctx, "./test.db")
+	var err error
+	db, err = database.NewDB(ctx, "./test.db")
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "%+v\n", err)
 		os.Exit(1)
@@ -36,6 +38,8 @@ func TestMain(m *testing.M) {
 		switch key {
 		case "DATA_ENCRYPTION_KEY":
 			return "hP3ZSCnY3LMgfTQjwTaGrhKwdA0yXMXIfv67OJnntqM="
+		case "VERSIONS_HISTORY_LIMIT":
+			return "3"
 		default:
 			return ""
 		}

cmd/tfstated/post_test.go

@@ -30,6 +30,9 @@ func TestPost(t *testing.T) {
 		{"GET", url.URL{Path: "/test_post"}, nil, "the_test_post4", http.StatusOK, "/test_post"},
 		{"POST", url.URL{Path: "/test_post"}, strings.NewReader("the_test_post5"), "", http.StatusOK, "without lock ID in query string on a locked state"},
 		{"GET", url.URL{Path: "/test_post"}, nil, "the_test_post5", http.StatusOK, "/test_post"},
+		{"POST", url.URL{Path: "/test_post"}, strings.NewReader("the_test_post6"), "", http.StatusOK, "another post just to make sure the history limit works"},
+		{"POST", url.URL{Path: "/test_post"}, strings.NewReader("the_test_post7"), "", http.StatusOK, "another post just to make sure the history limit works"},
+		{"POST", url.URL{Path: "/test_post"}, strings.NewReader("the_test_post8"), "", http.StatusOK, "another post just to make sure the history limit works"},
 	}
 	for _, tt := range tests {
 		runHTTPRequest(tt.method, &tt.uri, tt.body, func(r *http.Response, err error) {
@@ -46,4 +49,15 @@ func TestPost(t *testing.T) {
 			}
 		})
 	}
+	var n int
+	err := db.QueryRow(`SELECT COUNT(versions.id)
+                   FROM versions
+                   JOIN states ON states.id = versions.state_id
+                   WHERE states.name = "/test_post"`).Scan(&n)
+	if err != nil {
+		t.Fatalf("failed to count versions for the /test_post state: %s", err)
+	}
+	if n != 3 {
+		t.Fatalf("there should only be 3 versions of the /test_post state, got %d", n)
+	}
 }

pkg/database/db.go

@@ -29,6 +29,7 @@ type DB struct {
 	ctx                  context.Context
 	dataEncryptionKey    scrypto.AES256Key
 	readDB               *sql.DB
+	versionsHistoryLimit int
 	writeDB              *sql.DB
 }
 
@@ -58,6 +59,7 @@ func NewDB(ctx context.Context, url string) (*DB, error) {
 	db := DB{
 		ctx:                  ctx,
 		readDB:               readDB,
+		versionsHistoryLimit: 64,
 		writeDB:              writeDB,
 	}
 	if _, err = db.Exec("PRAGMA foreign_keys = ON"); err != nil {
@@ -101,3 +103,7 @@ func (db *DB) QueryRow(query string, args ...any) *sql.Row {
 func (db *DB) SetDataEncryptionKey(s string) error {
 	return db.dataEncryptionKey.FromBase64(s)
 }
+
+func (db *DB) SetVersionsHistoryLimit(n int) {
+	db.versionsHistoryLimit = n
+}

pkg/database/states.go

@@ -102,7 +102,8 @@ func (db *DB) SetState(name string, data []byte, lockID string) (bool, error) {
                                 JOIN states ON states.id = versions.state_id
                                 WHERE states.name = :name
                                 ORDER BY versions.id DESC
-                                LIMIT 64));`,
+                                LIMIT :limit));`,
+		sql.Named("limit", db.versionsHistoryLimit),
 		sql.Named("name", name),
 	)
 	if err != nil {