change transformer interface and watcher so that contract config is now fed into AddTransformers such that a single watcher can be loaded with transformers that use different cofigs

libraries/shared/contract_config.go

@@ -0,0 +1,17 @@
+package shared
+
+import (
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/vulcanize/vulcanizedb/pkg/filters"
+)
+
+type ContractConfig struct {
+	Address    string
+	Owner      string
+	Abi        string
+	ParsedAbi  abi.ABI
+	FirstBlock int64
+	LastBlock  int64
+	Name       string
+	Filters    []filters.LogFilter
+}

libraries/shared/transformer_interface.go

@@ -10,7 +10,7 @@ type Transformer interface {
 	Execute() error
 }
 
-type TransformerInitializer func(db *postgres.DB, blockchain core.BlockChain) Transformer
+type TransformerInitializer func(db *postgres.DB, blockchain core.BlockChain, con ContractConfig) (Transformer, error)
 
 func HexToInt64(byteString string) int64 {
 	value := common.HexToHash(byteString)

libraries/shared/watcher.go

@@ -11,11 +11,16 @@ type Watcher struct {
 	Blockchain   core.BlockChain
 }
 
-func (watcher *Watcher) AddTransformers(us []TransformerInitializer) {
+func (watcher *Watcher) AddTransformers(us []TransformerInitializer, con ContractConfig) error {
 	for _, transformerInitializer := range us {
-		transformer := transformerInitializer(&watcher.DB, watcher.Blockchain)
+		transformer, err := transformerInitializer(&watcher.DB, watcher.Blockchain, con)
+		if err != nil {
+			return err
+		}
 		watcher.Transformers = append(watcher.Transformers, transformer)
 	}
+
+	return nil
 }
 
 func (watcher *Watcher) Execute() error {

libraries/shared/watcher_test.go

@@ -23,15 +23,16 @@ func (mh *MockTransformer) Execute() error {
 	return nil
 }
 
-func fakeTransformerInitializer(db *postgres.DB, blockchain core.BlockChain) shared.Transformer {
-	return &MockTransformer{}
+func fakeTransformerInitializer(db *postgres.DB, blockchain core.BlockChain, con shared.ContractConfig) (shared.Transformer, error) {
+	return &MockTransformer{}, nil
 }
 
 var _ = Describe("Watcher", func() {
 	It("Adds transformers", func() {
 		watcher := shared.Watcher{}
+		con := shared.ContractConfig{}
 
-		watcher.AddTransformers([]shared.TransformerInitializer{fakeTransformerInitializer})
+		watcher.AddTransformers([]shared.TransformerInitializer{fakeTransformerInitializer}, con)
 
 		Expect(len(watcher.Transformers)).To(Equal(1))
 		Expect(watcher.Transformers).To(ConsistOf(&MockTransformer{}))
@@ -39,9 +40,10 @@ var _ = Describe("Watcher", func() {
 
 	It("Adds transformers from multiple sources", func() {
 		watcher := shared.Watcher{}
+		con := shared.ContractConfig{}
 
-		watcher.AddTransformers([]shared.TransformerInitializer{fakeTransformerInitializer})
-		watcher.AddTransformers([]shared.TransformerInitializer{fakeTransformerInitializer})
+		watcher.AddTransformers([]shared.TransformerInitializer{fakeTransformerInitializer}, con)
+		watcher.AddTransformers([]shared.TransformerInitializer{fakeTransformerInitializer}, con)
 
 		Expect(len(watcher.Transformers)).To(Equal(2))
 	})