Add endpoint for database deletion.

Executing a request against `DELETE /db` will now delete a database.

	curl -X DELETE "http://localhost:15000/db" -d '{"db":"d"}'

handler.go

@@ -106,6 +106,13 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		default:
 			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
 		}
+	case "/db":
+		switch r.Method {
+		case "DELETE":
+			h.handleDeleteDB(w, r)
+		default:
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		}
 	case "/db/attr/diff":
 		switch r.Method {
 		case "POST":
@@ -264,6 +271,33 @@ type sliceMaxResponse struct {
 	SliceMax uint64 `json:"SliceMax"`
 }
 
+// handleDeleteDB handles DELETE /db request.
+func (h *Handler) handleDeleteDB(w http.ResponseWriter, r *http.Request) {
+	// Decode request.
+	var req deleteDBRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// Delete database from the index.
+	if err := h.Index.DeleteDB(req.DB); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Encode response.
+	if err := json.NewEncoder(w).Encode(deleteDBResponse{}); err != nil {
+		h.logger().Printf("response encoding error: %s", err)
+	}
+}
+
+type deleteDBRequest struct {
+	DB string `json:"db"`
+}
+
+type deleteDBResponse struct{}
+
 // handlePostDBAttrDiff handles POST /db/attr/diff requests.
 func (h *Handler) handlePostDBAttrDiff(w http.ResponseWriter, r *http.Request) {
 	// Decode request.

handler_test.go

@@ -416,6 +416,42 @@ func TestHandler_Query_ErrParse(t *testing.T) {
 	}
 }
 
+// Ensure the handler can delete a database.
+func TestHandler_DB_Delete(t *testing.T) {
+	idx := MustOpenIndex()
+	defer idx.Close()
+
+	s := NewServer()
+	s.Handler.Index = idx.Index
+	defer s.Close()
+
+	// Create database.
+	if _, err := idx.CreateDBIfNotExists("d"); err != nil {
+		t.Fatal(err)
+	}
+
+	// Send request to delete database.
+	resp, err := http.DefaultClient.Do(MustNewHTTPRequest("DELETE", s.URL+"/db", strings.NewReader(`{"db":"d"}`)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	// Verify body response.
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("unexpected status: %d", resp.StatusCode)
+	} else if buf, err := ioutil.ReadAll(resp.Body); err != nil {
+		t.Fatal(err)
+	} else if string(buf) != "{}\n" {
+		t.Fatalf("unexpected response body: %s", buf)
+	}
+
+	// Verify database is gone.
+	if idx.DB("d") != nil {
+		t.Fatal("expected nil database")
+	}
+}
+
 // Ensure the handler can return data in differing blocks for a database.
 func TestHandler_DB_AttrStore_Diff(t *testing.T) {
 	idx := MustOpenIndex()

index.go

@@ -183,6 +183,33 @@ func (i *Index) createDBIfNotExists(name string) (*DB, error) {
 	return db, nil
 }
 
+// DeleteDB removes a database from the index.
+func (i *Index) DeleteDB(name string) error {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+
+	// Ignore if database doesn't exist.
+	db := i.db(name)
+	if db == nil {
+		return nil
+	}
+
+	// Close database.
+	if err := db.Close(); err != nil {
+		return err
+	}
+
+	// Delete database directory.
+	if err := os.RemoveAll(i.DBPath(name)); err != nil {
+		return err
+	}
+
+	// Remove reference.
+	delete(i.dbs, name)
+
+	return nil
+}
+
 // Frame returns the frame for a database and name.
 func (i *Index) Frame(db, name string) *Frame {
 	d := i.DB(db)

index_test.go

@@ -11,6 +11,39 @@ import (
 	"github.com/umbel/pilosa/pql"
 )
 
+// Ensure index can delete a database and its underlying files.
+func TestIndex_DeleteDB(t *testing.T) {
+	idx := MustOpenIndex()
+	defer idx.Close()
+
+	// Write bits to separate databases.
+	f0 := idx.MustCreateFragmentIfNotExists("d0", "f", 0)
+	if _, err := f0.SetBit(100, 200, nil, 0); err != nil {
+		t.Fatal(err)
+	}
+	f1 := idx.MustCreateFragmentIfNotExists("d1", "f", 0)
+	if _, err := f1.SetBit(100, 200, nil, 0); err != nil {
+		t.Fatal(err)
+	}
+
+	// Ensure d0 exists.
+	if _, err := os.Stat(idx.DBPath("d0")); err != nil {
+		t.Fatal(err)
+	}
+
+	// Delete d0.
+	if err := idx.DeleteDB("d0"); err != nil {
+		t.Fatal(err)
+	}
+
+	// Ensure d0 files are removed & d1 still exists.
+	if _, err := os.Stat(idx.DBPath("d0")); !os.IsNotExist(err) {
+		t.Fatal("expected d0 file deletion")
+	} else if _, err := os.Stat(idx.DBPath("d1")); err != nil {
+		t.Fatal("expected d1 files to still exist", err)
+	}
+}
+
 // Ensure index can sync with a remote index.
 func TestIndexSyncer_SyncIndex(t *testing.T) {
 	cluster := NewCluster(2)