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([]interface{}) ([]interface{}, error)
+	ToModels(contractAbi string, ethLog []core.HeaderSyncLog) ([]InsertionModel, 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, ", ")
+}