feat(tfstated): implement states locking

cmd/tfstated/lock.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"net/http"
+	"time"
+
+	"git.adyxax.org/adyxax/tfstated/pkg/database"
+)
+
+type lockRequest struct {
+	Created   time.Time `json:"Created"`
+	ID        string    `json:"ID"`
+	Info      string    `json:"Info"`
+	Operation string    `json:"Operation"`
+	Path      string    `json:"Path"`
+	Version   string    `json:"Version"`
+	Who       string    `json:"Who"`
+}
+
+func handleLock(db *database.DB) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/" {
+			_ = encode(w, http.StatusBadRequest,
+				fmt.Errorf("no state path provided, cannot LOCK /"))
+			return
+		}
+
+		var lock lockRequest
+		if err := decode(r, &lock); err != nil {
+			_ = encode(w, http.StatusBadRequest, err)
+			return
+		}
+		if success, err := db.SetLockOrGetExistingLock(r.URL.Path, &lock); err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				_ = encode(w, http.StatusNotFound,
+					fmt.Errorf("state path not found: %s", r.URL.Path))
+			} else {
+				_ = errorResponse(w, http.StatusInternalServerError, err)
+			}
+		} else if success {
+			w.WriteHeader(http.StatusOK)
+		} else {
+			_ = encode(w, http.StatusConflict, lock)
+		}
+	})
+}

cmd/tfstated/post.go

@@ -16,13 +16,20 @@ func handlePost(db *database.DB) http.Handler {
 			)
 			return
 		}
+
+		id := r.URL.Query().Get("ID")
+
 		data, err := io.ReadAll(r.Body)
 		if err != nil {
 			_ = errorResponse(w, http.StatusBadRequest, err)
 			return
 		}
-		if err := db.SetState(r.URL.Path, data); err != nil {
-			_ = errorResponse(w, http.StatusInternalServerError, err)
+		if idMismatch, err := db.SetState(r.URL.Path, data, id); err != nil {
+			if idMismatch {
+				_ = errorResponse(w, http.StatusConflict, err)
+			} else {
+				_ = errorResponse(w, http.StatusInternalServerError, err)
+			}
 		} else {
 			w.WriteHeader(http.StatusOK)
 		}

cmd/tfstated/routes.go

@@ -14,5 +14,7 @@ func addRoutes(
 
 	mux.Handle("DELETE /", handleDelete(db))
 	mux.Handle("GET /", handleGet(db))
+	mux.Handle("LOCK /", handleLock(db))
 	mux.Handle("POST /", handlePost(db))
+	mux.Handle("UNLOCK /", handleUnlock(db))
 }

cmd/tfstated/unlock.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"net/http"
+
+	"git.adyxax.org/adyxax/tfstated/pkg/database"
+)
+
+func handleUnlock(db *database.DB) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/" {
+			_ = encode(w, http.StatusBadRequest,
+				fmt.Errorf("no state path provided, cannot LOCK /"))
+			return
+		}
+
+		var lock lockRequest
+		if err := decode(r, &lock); err != nil {
+			_ = encode(w, http.StatusBadRequest, err)
+			return
+		}
+		if success, err := db.Unlock(r.URL.Path, &lock); err != nil {
+			if errors.Is(err, sql.ErrNoRows) {
+				_ = encode(w, http.StatusNotFound,
+					fmt.Errorf("state path not found: %s", r.URL.Path))
+			} else {
+				_ = errorResponse(w, http.StatusInternalServerError, err)
+			}
+		} else if success {
+			w.WriteHeader(http.StatusOK)
+		} else {
+			_ = encode(w, http.StatusConflict, lock)
+		}
+	})
+}