Skeleton Implementation of Solana Chain Reader Service (#610)

* Skeleton Implementation of Solana Chain Reader Service

This commit adds a new package that contains a limited chain reader for solana that implements the basic
interfaces of ServiceCtx and ChainReader. All functions required for ServiceCtx are complete and included
in a test. All functions required for ChainReader return an 'unimplemented' error.

* fix duplicate imports

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/smartcontractkit/chainlink-common v0.1.7-0.20240213113935-001c2f4befd4
 	github.com/smartcontractkit/libocr v0.0.0-20240112202000-6359502d2ff1
 	github.com/stretchr/testify v1.8.4
+	github.com/test-go/testify v1.1.4
 	go.uber.org/multierr v1.11.0
 	go.uber.org/zap v1.26.0
 	golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa

pkg/solana/chain_reader.go

@@ -0,0 +1,74 @@
+package solana
+
+import (
+	"context"
+
+	"github.com/smartcontractkit/chainlink-common/pkg/logger"
+	"github.com/smartcontractkit/chainlink-common/pkg/services"
+	"github.com/smartcontractkit/chainlink-common/pkg/types"
+)
+
+const ServiceName = "SolanaChainReader"
+
+type SolanaChainReaderService struct {
+	lggr logger.Logger
+	services.StateMachine
+}
+
+var (
+	_ services.Service  = &SolanaChainReaderService{}
+	_ types.ChainReader = &SolanaChainReaderService{}
+)
+
+// NewChainReaderService is a constructor for a new ChainReaderService for Solana. Returns a nil service on error.
+func NewChainReaderService(lggr logger.Logger) (*SolanaChainReaderService, error) {
+	return &SolanaChainReaderService{
+		lggr: logger.Named(lggr, ServiceName),
+	}, nil
+}
+
+// Name implements the services.ServiceCtx interface and returns the logger service name.
+func (s *SolanaChainReaderService) Name() string {
+	return s.lggr.Name()
+}
+
+// Start implements the services.ServiceCtx interface and starts necessary background services.
+// An error is returned if starting any internal services fails. Subsequent calls to Start return
+// and error.
+func (s *SolanaChainReaderService) Start(_ context.Context) error {
+	return s.StartOnce(ServiceName, func() error {
+		return nil
+	})
+}
+
+// Close implements the services.ServiceCtx interface and stops all background services and cleans
+// up used resources. Subsequent calls to Close return an error.
+func (s *SolanaChainReaderService) Close() error {
+	return s.StopOnce(ServiceName, func() error {
+		return nil
+	})
+}
+
+// Ready implements the services.ServiceCtx interface and returns an error if starting the service
+// encountered any errors or if the service is not ready to serve requests.
+func (s *SolanaChainReaderService) Ready() error {
+	return s.StateMachine.Ready()
+}
+
+// HealthReport implements the services.ServiceCtx interface and returns errors for any internal
+// function or service that may have failed.
+func (s *SolanaChainReaderService) HealthReport() map[string]error {
+	return map[string]error{s.Name(): s.Healthy()}
+}
+
+// GetLatestValue implements the types.ChainReader interface and requests and parses on-chain
+// data named by the provided contract, method, and params.
+func (s *SolanaChainReaderService) GetLatestValue(_ context.Context, contractName, method string, params any, returnVal any) error {
+	return types.UnimplementedError("GetLatestValue not available")
+}
+
+// Bind implements the types.ChainReader interface and allows new contract bindings to be added
+// to the service.
+func (s *SolanaChainReaderService) Bind(_ context.Context, bindings []types.BoundContract) error {
+	return types.UnimplementedError("Bind not available")
+}

pkg/solana/chain_reader_test.go

@@ -0,0 +1,37 @@
+package solana_test
+
+import (
+	"testing"
+
+	"github.com/test-go/testify/require"
+
+	"github.com/smartcontractkit/chainlink-common/pkg/logger"
+	"github.com/smartcontractkit/chainlink-common/pkg/utils/tests"
+
+	"github.com/smartcontractkit/chainlink-solana/pkg/solana"
+)
+
+func TestSolanaChainReaderService_ServiceCtx(t *testing.T) {
+	t.Parallel()
+
+	ctx := tests.Context(t)
+	svc, err := solana.NewChainReaderService(logger.Test(t))
+
+	require.NoError(t, err)
+	require.NotNil(t, svc)
+
+	require.Error(t, svc.Ready())
+	require.Len(t, svc.HealthReport(), 1)
+	require.Contains(t, svc.HealthReport(), solana.ServiceName)
+	require.Error(t, svc.HealthReport()[solana.ServiceName])
+
+	require.NoError(t, svc.Start(ctx))
+	require.NoError(t, svc.Ready())
+	require.Equal(t, map[string]error{solana.ServiceName: nil}, svc.HealthReport())
+
+	require.Error(t, svc.Start(ctx))
+
+	require.NoError(t, svc.Close())
+	require.Error(t, svc.Ready())
+	require.Error(t, svc.Close())
+}