VDB-919 Generalise converter (#152)

* Generalise transformer stack to use InsertionModel

* Add tests for event repository

* Restrict accepted values in InsertionModel

* Add call to repository.SetDB

* Improve error propagation/clarity on GetABI()

* Remove maker references in example

* Please golint

* refactor rollback error handling in repository

* Cleaner errors in repository, refactor tests

integration_test/integration_test_suite_test.go

@@ -17,6 +17,8 @@
 package integration_test
 
 import (
+	"github.com/sirupsen/logrus"
+	"io/ioutil"
 	"testing"
 
 	. "github.com/onsi/ginkgo"
@@ -27,3 +29,7 @@ func TestIntegrationTest(t *testing.T) {
 	RegisterFailHandler(Fail)
 	RunSpecs(t, "IntegrationTest Suite")
 }
+
+var _ = BeforeSuite(func() {
+	logrus.SetOutput(ioutil.Discard)
+})

libraries/shared/factories/event/converter.go

@@ -16,9 +16,13 @@
 
 package event
 
-import "github.com/vulcanize/vulcanizedb/pkg/core"
+import (
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+)
 
+// Converter transforms log data into general InsertionModels the Repository can persist__
 type Converter interface {
-	ToEntities(contractAbi string, ethLog []core.HeaderSyncLog) ([]interface{}, error)
+	ToModels(contractAbi string, ethLog []core.HeaderSyncLog) ([]InsertionModel, error)
-	ToModels([]interface{}) ([]interface{}, error)
+	SetDB(db *postgres.DB)
 }

libraries/shared/factories/event/repository.go

@@ -16,9 +16,163 @@
 
 package event
 
-import "github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+import (
+	"database/sql/driver"
+	"fmt"
+	"github.com/vulcanize/vulcanizedb/utils"
+	"strings"
 
+	"github.com/sirupsen/logrus"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+)
+
+const SetLogTransformedQuery = `UPDATE public.header_sync_logs SET transformed = true WHERE id = $1`
+
+// Repository persists transformed values to the DB
 type Repository interface {
-	Create(models []interface{}) error
+	Create(models []InsertionModel) error
 	SetDB(db *postgres.DB)
 }
+
+// LogFK is the name of log foreign key columns
+const LogFK ColumnName = "log_id"
+
+// AddressFK is the name of address foreign key columns
+const AddressFK ColumnName = "address_id"
+
+// HeaderFK is the name of header foreign key columns
+const HeaderFK ColumnName = "header_id"
+
+// SchemaName is the schema to work with
+type SchemaName string
+
+// TableName identifies the table for inserting the data
+type TableName string
+
+// ColumnName identifies columns on the given table
+type ColumnName string
+
+// ColumnValues maps a column to the value for insertion. This is restricted to []byte, bool, float64, int64, string, time.Time
+type ColumnValues map[ColumnName]interface{}
+
+// ErrUnsupportedValue is thrown when a model supplies a type of value the postgres driver cannot handle.
+var ErrUnsupportedValue = func(value interface{}) error {
+	return fmt.Errorf("unsupported type of value supplied in model: %v (%T)", value, value)
+}
+
+// InsertionModel is the generalised data structure a converter returns, and contains everything the repository needs to
+// persist the converted data.
+type InsertionModel struct {
+	SchemaName     SchemaName
+	TableName      TableName
+	OrderedColumns []ColumnName // Defines the fields to insert, and in which order the table expects them
+	ColumnValues   ColumnValues // Associated values for columns, restricted to []byte, bool, float64, int64, string, time.Time
+}
+
+// ModelToQuery stores memoised insertion queries to minimise computation
+var ModelToQuery = map[string]string{}
+
+// GetMemoizedQuery gets/creates a DB insertion query for the model
+func GetMemoizedQuery(model InsertionModel) string {
+	// The schema and table name uniquely determines the insertion query, use that for memoization
+	queryKey := string(model.SchemaName) + string(model.TableName)
+	query, queryMemoized := ModelToQuery[queryKey]
+	if !queryMemoized {
+		query = GenerateInsertionQuery(model)
+		ModelToQuery[queryKey] = query
+	}
+	return query
+}
+
+// GenerateInsertionQuery creates an SQL insertion query from an insertion model.
+// Should be called through GetMemoizedQuery, so the query is not generated on each call to Create.
+func GenerateInsertionQuery(model InsertionModel) string {
+	var valuePlaceholders []string
+	var updateOnConflict []string
+	for i := 0; i < len(model.OrderedColumns); i++ {
+		valuePlaceholder := fmt.Sprintf("$%d", 1+i)
+		valuePlaceholders = append(valuePlaceholders, valuePlaceholder)
+		updateOnConflict = append(updateOnConflict,
+			fmt.Sprintf("%s = %s", model.OrderedColumns[i], valuePlaceholder))
+	}
+
+	baseQuery := `INSERT INTO %v.%v (%v) VALUES(%v)
+		ON CONFLICT (header_id, log_id) DO UPDATE SET %v;`
+
+	return fmt.Sprintf(baseQuery,
+		model.SchemaName,
+		model.TableName,
+		joinOrderedColumns(model.OrderedColumns),
+		strings.Join(valuePlaceholders, ", "),
+		strings.Join(updateOnConflict, ", "))
+}
+
+/*
+Create generates an insertion query and persists to the DB, given a slice of InsertionModels.
+ColumnValues are restricted to []byte, bool, float64, int64, string, time.Time.
+
+testModel = shared.InsertionModel{
+	SchemaName:     "public"
+	TableName:      "testEvent",
+	OrderedColumns: []string{"header_id", "log_id", "variable1"},
+	ColumnValues: ColumnValues{
+		"header_id": 303
+		"log_id":   "808",
+		"variable1": "value1",
+	},
+}
+*/
+func Create(models []InsertionModel, db *postgres.DB) error {
+	if len(models) == 0 {
+		return fmt.Errorf("repository got empty model slice")
+	}
+
+	tx, dbErr := db.Beginx()
+	if dbErr != nil {
+		return dbErr
+	}
+
+	for _, model := range models {
+		// Maps can't be iterated over in a reliable manner, so we rely on OrderedColumns to define the order to insert
+		// tx.Exec is variadically typed in the args, so if we wrap in []interface{} we can apply them all automatically
+		var args []interface{}
+		for _, col := range model.OrderedColumns {
+			value := model.ColumnValues[col]
+			// Check whether or not PG can accept the type of value in the model
+			okPgValue := driver.IsValue(value)
+			if !okPgValue {
+				logrus.WithField("model", model).Errorf("PG cannot handle value of this type: %T", value)
+				return ErrUnsupportedValue(value)
+			}
+			args = append(args, value)
+		}
+
+		insertionQuery := GetMemoizedQuery(model)
+		_, execErr := tx.Exec(insertionQuery, args...) // couldn't pass varying types in bulk with args :: []string
+
+		if execErr != nil {
+			rollbackErr := tx.Rollback()
+			if rollbackErr != nil {
+				logrus.Error("failed to rollback ", rollbackErr)
+			}
+			return execErr
+		}
+
+		_, logErr := tx.Exec(SetLogTransformedQuery, model.ColumnValues[LogFK])
+
+		if logErr != nil {
+			utils.RollbackAndLogFailure(tx, logErr, "header_sync_logs.transformed")
+			return logErr
+		}
+	}
+
+	return tx.Commit()
+}
+
+func joinOrderedColumns(columns []ColumnName) string {
+	var stringColumns []string
+	for _, columnName := range columns {
+		stringColumns = append(stringColumns, string(columnName))
+	}
+	return strings.Join(stringColumns, ", ")
+}

libraries/shared/factories/event/repository_test.go

@@ -0,0 +1,204 @@
+// VulcanizeDB
+// Copyright © 2019 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package event_test
+
+import (
+	"fmt"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/libraries/shared/factories/event"
+	"github.com/vulcanize/vulcanizedb/libraries/shared/test_data"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres/repositories"
+	"github.com/vulcanize/vulcanizedb/pkg/fakes"
+	"github.com/vulcanize/vulcanizedb/test_config"
+	"math/big"
+)
+
+var _ = Describe("Repository", func() {
+	var db *postgres.DB
+
+	BeforeEach(func() {
+		db = test_config.NewTestDB(test_config.NewTestNode())
+		test_config.CleanTestDB(db)
+	})
+
+	Describe("Create", func() {
+		const createTestEventTableQuery = `CREATE TABLE public.testEvent(
+		id        SERIAL PRIMARY KEY,
+		header_id INTEGER NOT NULL REFERENCES headers (id) ON DELETE CASCADE,
+		log_id    BIGINT  NOT NULL REFERENCES header_sync_logs (id) ON DELETE CASCADE,
+		variable1 TEXT,
+		UNIQUE (header_id, log_id)
+		);`
+
+		var (
+			headerID, logID  int64
+			headerRepository repositories.HeaderRepository
+			testModel        event.InsertionModel
+		)
+
+		BeforeEach(func() {
+			_, tableErr := db.Exec(createTestEventTableQuery)
+			Expect(tableErr).NotTo(HaveOccurred())
+			headerRepository = repositories.NewHeaderRepository(db)
+			var insertHeaderErr error
+			headerID, insertHeaderErr = headerRepository.CreateOrUpdateHeader(fakes.FakeHeader)
+			Expect(insertHeaderErr).NotTo(HaveOccurred())
+			headerSyncLog := test_data.CreateTestLog(headerID, db)
+			logID = headerSyncLog.ID
+
+			testModel = event.InsertionModel{
+				SchemaName: "public",
+				TableName:  "testEvent",
+				OrderedColumns: []event.ColumnName{
+					event.HeaderFK, event.LogFK, "variable1",
+				},
+				ColumnValues: event.ColumnValues{
+					event.HeaderFK: headerID,
+					event.LogFK:    logID,
+					"variable1":    "value1",
+				},
+			}
+		})
+
+		AfterEach(func() {
+			db.MustExec(`DROP TABLE public.testEvent;`)
+		})
+
+		// Needs to run before the other tests, since those insert keys in map
+		It("memoizes queries", func() {
+			Expect(len(event.ModelToQuery)).To(Equal(0))
+			event.GetMemoizedQuery(testModel)
+			Expect(len(event.ModelToQuery)).To(Equal(1))
+			event.GetMemoizedQuery(testModel)
+			Expect(len(event.ModelToQuery)).To(Equal(1))
+		})
+
+		It("persists a model to postgres", func() {
+			createErr := event.Create([]event.InsertionModel{testModel}, db)
+			Expect(createErr).NotTo(HaveOccurred())
+
+			var res TestEvent
+			dbErr := db.Get(&res, `SELECT log_id, variable1 FROM public.testEvent;`)
+			Expect(dbErr).NotTo(HaveOccurred())
+
+			Expect(res.LogID).To(Equal(fmt.Sprint(testModel.ColumnValues[event.LogFK])))
+			Expect(res.Variable1).To(Equal(testModel.ColumnValues["variable1"]))
+		})
+
+		Describe("returns errors", func() {
+			It("for empty model slice", func() {
+				err := event.Create([]event.InsertionModel{}, db)
+				Expect(err).To(MatchError("repository got empty model slice"))
+			})
+
+			It("for failed SQL inserts", func() {
+				header := fakes.GetFakeHeader(1)
+				headerID, headerErr := headerRepository.CreateOrUpdateHeader(header)
+				Expect(headerErr).NotTo(HaveOccurred())
+
+				brokenModel := event.InsertionModel{
+					SchemaName: "public",
+					TableName:  "testEvent",
+					// Wrong name of last column compared to DB, will generate incorrect query
+					OrderedColumns: []event.ColumnName{
+						event.HeaderFK, event.LogFK, "variable2",
+					},
+					ColumnValues: event.ColumnValues{
+						event.HeaderFK: headerID,
+						event.LogFK:    logID,
+						"variable1":    "value1",
+					},
+				}
+
+				// Remove cached queries, or we won't generate a new (incorrect) one
+				delete(event.ModelToQuery, "publictestEvent")
+
+				createErr := event.Create([]event.InsertionModel{brokenModel}, db)
+				// Remove incorrect query, so other tests won't get it
+				delete(event.ModelToQuery, "publictestEvent")
+
+				Expect(createErr).To(HaveOccurred())
+			})
+
+			It("for unsupported types in ColumnValue", func() {
+				unsupportedValue := big.NewInt(5)
+				testModel = event.InsertionModel{
+					SchemaName: "public",
+					TableName:  "testEvent",
+					OrderedColumns: []event.ColumnName{
+						event.HeaderFK, event.LogFK, "variable1",
+					},
+					ColumnValues: event.ColumnValues{
+						event.HeaderFK: headerID,
+						event.LogFK:    logID,
+						"variable1":    unsupportedValue,
+					},
+				}
+
+				createErr := event.Create([]event.InsertionModel{testModel}, db)
+				Expect(createErr).To(MatchError(event.ErrUnsupportedValue(unsupportedValue)))
+			})
+		})
+
+		It("upserts queries with conflicting source", func() {
+			conflictingModel := event.InsertionModel{
+				SchemaName: "public",
+				TableName:  "testEvent",
+				OrderedColumns: []event.ColumnName{
+					event.HeaderFK, event.LogFK, "variable1",
+				},
+				ColumnValues: event.ColumnValues{
+					event.HeaderFK: headerID,
+					event.LogFK:    logID,
+					"variable1":    "conflictingValue",
+				},
+			}
+
+			createErr := event.Create([]event.InsertionModel{testModel, conflictingModel}, db)
+			Expect(createErr).NotTo(HaveOccurred())
+
+			var res TestEvent
+			dbErr := db.Get(&res, `SELECT log_id, variable1 FROM public.testEvent;`)
+			Expect(dbErr).NotTo(HaveOccurred())
+			Expect(res.Variable1).To(Equal(conflictingModel.ColumnValues["variable1"]))
+		})
+
+		It("generates correct queries", func() {
+			actualQuery := event.GenerateInsertionQuery(testModel)
+			expectedQuery := `INSERT INTO public.testEvent (header_id, log_id, variable1) VALUES($1, $2, $3)
+		ON CONFLICT (header_id, log_id) DO UPDATE SET header_id = $1, log_id = $2, variable1 = $3;`
+			Expect(actualQuery).To(Equal(expectedQuery))
+		})
+
+		It("marks log transformed", func() {
+			createErr := event.Create([]event.InsertionModel{testModel}, db)
+			Expect(createErr).NotTo(HaveOccurred())
+
+			var logTransformed bool
+			getErr := db.Get(&logTransformed, `SELECT transformed FROM public.header_sync_logs WHERE id = $1`, logID)
+			Expect(getErr).NotTo(HaveOccurred())
+			Expect(logTransformed).To(BeTrue())
+		})
+	})
+})
+
+type TestEvent struct {
+	LogID     string `db:"log_id"`
+	Variable1 string
+}

libraries/shared/factories/event/transformer.go

@@ -30,6 +30,7 @@ type Transformer struct {
 }
 
 func (transformer Transformer) NewTransformer(db *postgres.DB) transformer.EventTransformer {
+	transformer.Converter.SetDB(db)
 	transformer.Repository.SetDB(db)
 	return transformer
 }
@@ -42,13 +43,7 @@ func (transformer Transformer) Execute(logs []core.HeaderSyncLog) error {
 		return nil
 	}
 
-	entities, err := transformer.Converter.ToEntities(config.ContractAbi, logs)
+	models, err := transformer.Converter.ToModels(config.ContractAbi, logs)
-	if err != nil {
-		logrus.Errorf("error converting logs to entities in %v: %v", transformerName, err)
-		return err
-	}
-
-	models, err := transformer.Converter.ToModels(entities)
 	if err != nil {
 		logrus.Errorf("error converting entities to models in %v: %v", transformerName, err)
 		return err

libraries/shared/factories/event/transformer_test.go

@@ -66,12 +66,11 @@ var _ = Describe("Transformer", func() {
 		err := t.Execute([]core.HeaderSyncLog{})
 
 		Expect(err).NotTo(HaveOccurred())
-		Expect(converter.ToEntitiesCalledCounter).To(Equal(0))
 		Expect(converter.ToModelsCalledCounter).To(Equal(0))
 		Expect(repository.CreateCalledCounter).To(Equal(0))
 	})
 
-	It("converts an eth log to an entity", func() {
+	It("converts an eth log to a model", func() {
 		err := t.Execute(logs)
 
 		Expect(err).NotTo(HaveOccurred())
@@ -79,26 +78,7 @@ var _ = Describe("Transformer", func() {
 		Expect(converter.LogsToConvert).To(Equal(logs))
 	})
 
-	It("returns an error if converter fails", func() {
-		converter.ToEntitiesError = fakes.FakeError
-
-		err := t.Execute(logs)
-
-		Expect(err).To(HaveOccurred())
-		Expect(err).To(MatchError(fakes.FakeError))
-	})
-
-	It("converts an entity to a model", func() {
-		converter.EntitiesToReturn = []interface{}{test_data.GenericEntity{}}
-
-		err := t.Execute(logs)
-
-		Expect(err).NotTo(HaveOccurred())
-		Expect(converter.EntitiesToConvert[0]).To(Equal(test_data.GenericEntity{}))
-	})
-
 	It("returns an error if converting to models fails", func() {
-		converter.EntitiesToReturn = []interface{}{test_data.GenericEntity{}}
 		converter.ToModelsError = fakes.FakeError
 
 		err := t.Execute(logs)
@@ -108,12 +88,12 @@ var _ = Describe("Transformer", func() {
 	})
 
 	It("persists the record", func() {
-		converter.ModelsToReturn = []interface{}{test_data.GenericModel{}}
+		converter.ModelsToReturn = []event.InsertionModel{test_data.GenericModel}
 
 		err := t.Execute(logs)
 
 		Expect(err).NotTo(HaveOccurred())
-		Expect(repository.PassedModels[0]).To(Equal(test_data.GenericModel{}))
+		Expect(repository.PassedModels[0]).To(Equal(test_data.GenericModel))
 	})
 
 	It("returns error if persisting the record fails", func() {

libraries/shared/mocks/event_converter.go

@@ -16,41 +16,29 @@
 
 package mocks
 
-import "github.com/vulcanize/vulcanizedb/pkg/core"
+import (
+	"github.com/vulcanize/vulcanizedb/libraries/shared/factories/event"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+)
 
 type MockConverter struct {
-	ToEntitiesError         error
-	PassedContractAddresses []string
 	ToModelsError           error
-	entityConverterError    error
-	modelConverterError     error
 	ContractAbi             string
 	LogsToConvert           []core.HeaderSyncLog
-	EntitiesToConvert       []interface{}
+	ModelsToReturn          []event.InsertionModel
-	EntitiesToReturn        []interface{}
+	PassedContractAddresses []string
-	ModelsToReturn          []interface{}
+	SetDBCalled             bool
-	ToEntitiesCalledCounter int
 	ToModelsCalledCounter   int
 }
 
-func (converter *MockConverter) ToEntities(contractAbi string, ethLogs []core.HeaderSyncLog) ([]interface{}, error) {
+func (converter *MockConverter) ToModels(abi string, logs []core.HeaderSyncLog) ([]event.InsertionModel, error) {
-	for _, log := range ethLogs {
+	converter.LogsToConvert = logs
-		converter.PassedContractAddresses = append(converter.PassedContractAddresses, log.Log.Address.Hex())
+	converter.ContractAbi = abi
-	}
+	converter.ToModelsCalledCounter = converter.ToModelsCalledCounter + 1
-	converter.ContractAbi = contractAbi
-	converter.LogsToConvert = ethLogs
-	return converter.EntitiesToReturn, converter.ToEntitiesError
-}
-
-func (converter *MockConverter) ToModels(entities []interface{}) ([]interface{}, error) {
-	converter.EntitiesToConvert = entities
 	return converter.ModelsToReturn, converter.ToModelsError
 }
 
-func (converter *MockConverter) SetToEntityConverterError(err error) {
+func (converter *MockConverter) SetDB(db *postgres.DB) {
-	converter.entityConverterError = err
+	converter.SetDBCalled = true
-}
-
-func (converter *MockConverter) SetToModelConverterError(err error) {
-	converter.modelConverterError = err
 }

libraries/shared/mocks/event_repository.go

@@ -17,17 +17,18 @@
 package mocks
 
 import (
+	"github.com/vulcanize/vulcanizedb/libraries/shared/factories/event"
 	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 )
 
 type MockEventRepository struct {
 	createError         error
-	PassedModels        []interface{}
+	PassedModels        []event.InsertionModel
 	SetDbCalled         bool
 	CreateCalledCounter int
 }
 
-func (repository *MockEventRepository) Create(models []interface{}) error {
+func (repository *MockEventRepository) Create(models []event.InsertionModel) error {
 	repository.PassedModels = models
 	repository.CreateCalledCounter++
 

libraries/shared/test_data/generic.go

@@ -20,14 +20,12 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/vulcanize/vulcanizedb/libraries/shared/factories/event"
 	"github.com/vulcanize/vulcanizedb/libraries/shared/transformer"
 	"math/rand"
 	"time"
 )
 
-type GenericModel struct{}
-type GenericEntity struct{}
-
 var startingBlockNumber = rand.Int63()
 var topic0 = "0x" + randomString(64)
 
@@ -44,6 +42,8 @@ var GenericTestLog = func() types.Log {
 	}
 }
 
+var GenericModel = event.InsertionModel{}
+
 var GenericTestConfig = transformer.EventTransformerConfig{
 	TransformerName:     "generic-test-transformer",
 	ContractAddresses:   []string{fakeAddress().Hex()},

libraries/shared/test_data/test_helpers.go

@@ -0,0 +1,37 @@
+package test_data
+
+import (
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	. "github.com/onsi/gomega"
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
+	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres/repositories"
+	"math/rand"
+)
+
+// Create a header sync log to reference in an event, returning inserted header sync log
+func CreateTestLog(headerID int64, db *postgres.DB) core.HeaderSyncLog {
+	log := types.Log{
+		Address:     common.Address{},
+		Topics:      nil,
+		Data:        nil,
+		BlockNumber: 0,
+		TxHash:      common.Hash{},
+		TxIndex:     uint(rand.Int31()),
+		BlockHash:   common.Hash{},
+		Index:       0,
+		Removed:     false,
+	}
+	headerSyncLogRepository := repositories.NewHeaderSyncLogRepository(db)
+	insertLogsErr := headerSyncLogRepository.CreateHeaderSyncLogs(headerID, []types.Log{log})
+	Expect(insertLogsErr).NotTo(HaveOccurred())
+	headerSyncLogs, getLogsErr := headerSyncLogRepository.GetUntransformedHeaderSyncLogs()
+	Expect(getLogsErr).NotTo(HaveOccurred())
+	for _, headerSyncLog := range headerSyncLogs {
+		if headerSyncLog.Log.TxIndex == log.TxIndex {
+			return headerSyncLog
+		}
+	}
+	panic("couldn't find inserted test log")
+}

pkg/contract_watcher/shared/getter/getter_test.go

@@ -47,7 +47,8 @@ var _ = Describe("Interface Getter", func() {
 			transactionConverter := rpc2.NewRpcTransactionConverter(ethClient)
 			blockChain := geth.NewBlockChain(blockChainClient, rpcClient, node, transactionConverter)
 			interfaceGetter := getter.NewInterfaceGetter(blockChain)
-			abi := interfaceGetter.GetABI(constants.PublicResolverAddress, blockNumber)
+			abi, err := interfaceGetter.GetABI(constants.PublicResolverAddress, blockNumber)
+			Expect(err).NotTo(HaveOccurred())
 			Expect(abi).To(Equal(expectedABI))
 			_, err = geth.ParseAbi(abi)
 			Expect(err).ToNot(HaveOccurred())

pkg/contract_watcher/shared/getter/interface_getter.go

@@ -17,6 +17,7 @@
 package getter
 
 import (
+	"fmt"
 	"github.com/vulcanize/vulcanizedb/pkg/contract_watcher/shared/constants"
 	"github.com/vulcanize/vulcanizedb/pkg/contract_watcher/shared/fetcher"
 	"github.com/vulcanize/vulcanizedb/pkg/core"
@@ -40,14 +41,18 @@ func NewInterfaceGetter(blockChain core.BlockChain) *interfaceGetter {
 }
 
 // Used to construct a custom ABI based on the results from calling supportsInterface
-func (g *interfaceGetter) GetABI(resolverAddr string, blockNumber int64) string {
+func (g *interfaceGetter) GetABI(resolverAddr string, blockNumber int64) (string, error) {
 	a := constants.SupportsInterfaceABI
 	args := make([]interface{}, 1)
 	args[0] = constants.MetaSig.Bytes()
 	supports, err := g.getSupportsInterface(a, resolverAddr, blockNumber, args)
-	if err != nil || !supports {
+	if err != nil {
-		return ""
+		return "", fmt.Errorf("call to getSupportsInterface failed: %v", err)
 	}
+	if !supports {
+		return "", fmt.Errorf("contract does not support interface")
+	}
+
 	abiStr := `[`
 	args[0] = constants.AddrChangeSig.Bytes()
 	supports, err = g.getSupportsInterface(a, resolverAddr, blockNumber, args)
@@ -91,7 +96,7 @@ func (g *interfaceGetter) GetABI(resolverAddr string, blockNumber int64) string
 	}
 	abiStr = abiStr[:len(abiStr)-1] + `]`
 
-	return abiStr
+	return abiStr, nil
 }
 
 // Use this method to check whether or not a contract supports a given method/event interface

utils/utils.go

@@ -17,7 +17,8 @@
 package utils
 
 import (
-	log "github.com/sirupsen/logrus"
+	"github.com/jmoiron/sqlx"
+	logrus "github.com/sirupsen/logrus"
 	"math/big"
 	"os"
 	"path/filepath"
@@ -31,7 +32,7 @@ import (
 func LoadPostgres(database config.Database, node core.Node) postgres.DB {
 	db, err := postgres.NewDB(database, node)
 	if err != nil {
-		log.Fatal("Error loading postgres: ", err)
+		logrus.Fatal("Error loading postgres: ", err)
 	}
 	return *db
 }
@@ -40,7 +41,7 @@ func ReadAbiFile(abiFilepath string) string {
 	abiFilepath = AbsFilePath(abiFilepath)
 	abi, err := geth.ReadAbiFile(abiFilepath)
 	if err != nil {
-		log.Fatalf("Error reading ABI file at \"%s\"\n %v", abiFilepath, err)
+		logrus.Fatalf("Error reading ABI file at \"%s\"\n %v", abiFilepath, err)
 	}
 	return abi
 }
@@ -60,12 +61,12 @@ func GetAbi(abiFilepath string, contractHash string, network string) string {
 	} else {
 		url := geth.GenURL(network)
 		etherscan := geth.NewEtherScanClient(url)
-		log.Printf("No ABI supplied. Retrieving ABI from Etherscan: %s", url)
+		logrus.Printf("No ABI supplied. Retrieving ABI from Etherscan: %s", url)
 		contractAbiString, _ = etherscan.GetAbi(contractHash)
 	}
 	_, err := geth.ParseAbi(contractAbiString)
 	if err != nil {
-		log.Fatalln("Invalid ABI: ", err)
+		logrus.Fatalln("Invalid ABI: ", err)
 	}
 	return contractAbiString
 }
@@ -79,3 +80,11 @@ func RequestedBlockNumber(blockNumber *int64) *big.Int {
 	}
 	return _blockNumber
 }
+
+func RollbackAndLogFailure(tx *sqlx.Tx, txErr error, fieldName string) {
+	rollbackErr := tx.Rollback()
+	if rollbackErr != nil {
+		logrus.WithFields(logrus.Fields{"rollbackErr": rollbackErr, "txErr": txErr}).
+			Warnf("failed to rollback transaction after failing to insert %s", fieldName)
+	}
+}