Transaction logs API endpoint (#438)

Co-authored-by: Peter Argue <89119817+peterargue@users.noreply.github.com>
Co-authored-by: Janez Podhostnik <67895329+janezpodhostnik@users.noreply.github.com>

Author: 3 people

emulator/blockchain.go

@@ -1641,3 +1641,12 @@ func (b *Blockchain) GetTransactionResultsByBlockID(blockID flowgo.Identifier) (
 	}
 	return results, nil
 }
+
+func (b *Blockchain) GetLogs(identifier flowgo.Identifier) ([]string, error) {
+	txResult, err := b.storage.TransactionResultByID(context.Background(), identifier)
+	if err != nil {
+		return nil, err
+
+	}
+	return txResult.Logs, nil
+}

emulator/emulator.go

@@ -162,6 +162,10 @@ type ExecutionCapable interface {
 	CommitBlock() (*flowgo.Block, error)
 }
 
+type LogProvider interface {
+	GetLogs(flowgo.Identifier) ([]string, error)
+}
+
 // Emulator defines the method set of an emulated emulator.
 type Emulator interface {
 	ServiceKey() ServiceKey
@@ -174,4 +178,5 @@ type Emulator interface {
 	RollbackCapable
 	AutoMineCapable
 	ExecutionCapable
+	LogProvider
 }

emulator/mocks/emulator.go

@@ -61,6 +61,8 @@ func NewEmulatorAPIServer(emulator emulator.Emulator, adapter *adapters.AccessAd
 	router.HandleFunc("/emulator/snapshots", r.SnapshotList).Methods("GET")
 	router.HandleFunc("/emulator/snapshots/{name}", r.SnapshotJump).Methods("PUT")
 
+	router.HandleFunc("/emulator/logs/{id}", r.Logs).Methods("GET")
+
 	router.HandleFunc("/emulator/storages/{address}", r.Storage)
 
 	router.HandleFunc("/emulator/config", r.Config)
@@ -271,3 +273,32 @@ func (m EmulatorAPIServer) ResetCodeCoverage(w http.ResponseWriter, r *http.Requ
 	m.emulator.ResetCoverageReport()
 	w.WriteHeader(http.StatusOK)
 }
+
+func (m EmulatorAPIServer) Logs(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	vars := mux.Vars(r)
+	id := vars["id"]
+
+	identifier, err := flowgo.HexStringToIdentifier(id)
+	if err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	logs, err := m.emulator.GetLogs(identifier)
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+
+	if len(logs) == 0 {
+		err = json.NewEncoder(w).Encode([]string{})
+	} else {
+		err = json.NewEncoder(w).Encode(logs)
+	}
+
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+}