Merge branch 'po-praefect-reconcile-progress' into 'master'

Reconciliation should report progress and warn user

Closes #2621

See merge request gitlab-org/gitaly!2084

9 files changed, 176 insertions, 81 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b6aaedfc5..08d05b215 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -94,6 +94,11 @@ proto:
   stage: test
   script:
     - make proto no-changes
+  artifacts:
+    paths:
+    - ruby/proto/gitaly/*
+    - proto/go/gitalypb/*
+    when: on_failure
 
 build:go1.14:
   <<: *build_definition
diff --git a/changelogs/unreleased/po-praefect-reconcile-progress.yml b/changelogs/unreleased/po-praefect-reconcile-progress.yml
new file mode 100644
index 000000000..564f5db84
--- /dev/null
+++ b/changelogs/unreleased/po-praefect-reconcile-progress.yml
@@ -0,0 +1,5 @@
+---
+title: Reconciliation should report progress and warn user
+merge_request: 2084
+author:
+type: added
diff --git a/cmd/praefect/main.go b/cmd/praefect/main.go
index 2526f0749..46a8f16e7 100644
--- a/cmd/praefect/main.go
+++ b/cmd/praefect/main.go
@@ -39,7 +39,8 @@
 // The subcommand "reconcile" performs a consistency check of a backend storage
 // against the primary or another storage in the same virtual storage group.
 //
-//     praefect -config PATH_TO_CONFIG reconcile -virtual <vstorage> -target <t-storage> [-reference <r-storage>]
+//     praefect -config PATH_TO_CONFIG reconcile -virtual <vstorage> -target
+//     <t-storage> [-reference <r-storage>] [-f]
 //
 // "-virtual" specifies which virtual storage the target and reference
 // belong to.
@@ -54,6 +55,9 @@
 // current primary. If the primary is the same as the target, an error will
 // occur.
 //
+// By default, a dry-run is performed where no replications are scheduled. When
+// the flag "-f" is provided, the replications will actually schedule.
+//
 // Dataloss
 //
 // The subcommand "dataloss" helps identify dataloss cases during a given
diff --git a/cmd/praefect/subcmd_reconcile.go b/cmd/praefect/subcmd_reconcile.go
index 42f64d6b4..d9431fe41 100644
--- a/cmd/praefect/subcmd_reconcile.go
+++ b/cmd/praefect/subcmd_reconcile.go
@@ -13,16 +13,18 @@ import (
 )
 
 type nodeReconciler struct {
-	conf             config.Config
-	virtualStorage   string
-	targetStorage    string
-	referenceStorage string
+	conf                  config.Config
+	virtualStorage        string
+	targetStorage         string
+	referenceStorage      string
+	disableReconciliation bool
 }
 
 type reconcileSubcommand struct {
 	virtual   string
 	target    string
 	reference string
+	force     bool
 }
 
 func (s *reconcileSubcommand) FlagSet() *flag.FlagSet {
@@ -30,15 +32,17 @@ func (s *reconcileSubcommand) FlagSet() *flag.FlagSet {
 	fs.StringVar(&s.virtual, "virtual", "", "virtual storage for target storage")
 	fs.StringVar(&s.target, "target", "", "target storage to reconcile")
 	fs.StringVar(&s.reference, "reference", "", "reference storage to reconcile (optional)")
+	fs.BoolVar(&s.force, "f", false, "actually schedule replications")
 	return fs
 }
 
 func (s *reconcileSubcommand) Exec(flags *flag.FlagSet, conf config.Config) error {
 	nr := nodeReconciler{
-		conf:             conf,
-		virtualStorage:   s.virtual,
-		targetStorage:    s.target,
-		referenceStorage: s.reference,
+		conf:                  conf,
+		virtualStorage:        s.virtual,
+		targetStorage:         s.target,
+		referenceStorage:      s.reference,
+		disableReconciliation: !s.force,
 	}
 
 	if err := nr.reconcile(); err != nil {
@@ -76,16 +80,24 @@ func (nr nodeReconciler) reconcile() error {
 
 	pCli := gitalypb.NewPraefectInfoServiceClient(cc)
 
+	if nr.disableReconciliation {
+		log.Print("Performing a DRY RUN - no changes will be made until '-f' flag is provided")
+	} else {
+		log.Print("Performing a LIVE RUN - any repositories on target that are inconsistent with reference will be overwritten with the version present on reference")
+	}
+
 	request := &gitalypb.ConsistencyCheckRequest{
-		VirtualStorage:   nr.virtualStorage,
-		TargetStorage:    nr.targetStorage,
-		ReferenceStorage: nr.referenceStorage,
+		VirtualStorage:         nr.virtualStorage,
+		TargetStorage:          nr.targetStorage,
+		ReferenceStorage:       nr.referenceStorage,
+		DisableReconcilliation: nr.disableReconciliation,
 	}
 	stream, err := pCli.ConsistencyCheck(context.TODO(), request)
 	if err != nil {
 		return err
 	}
 
+	log.Print("Checking consistency...")
 	if err := nr.consumeStream(stream); err != nil {
 		return err
 	}
@@ -134,7 +146,10 @@ func (nr nodeReconciler) validateArgs() error {
 }
 
 func (nr nodeReconciler) consumeStream(stream gitalypb.PraefectInfoService_ConsistencyCheckClient) error {
-	for {
+	var rStorage string
+	var i uint
+
+	for ; ; i++ {
 		resp, err := stream.Recv()
 		if err == io.EOF {
 			break
@@ -143,13 +158,39 @@ func (nr nodeReconciler) consumeStream(stream gitalypb.PraefectInfoService_Consi
 			return err
 		}
 
-		if resp.GetReferenceChecksum() != resp.GetTargetChecksum() {
+		if resp.ReferenceStorage != rStorage {
+			rStorage = resp.ReferenceStorage
+			log.Print("Reference storage being used: " + rStorage)
+		}
+
+		if resp.GetReferenceChecksum() == resp.GetTargetChecksum() {
+			log.Print("CONSISTENT: " + resp.GetRepoRelativePath())
+			continue
+		}
+
+		checksumPrint := func(checksum string) string {
+			if checksum == "" {
+				return "null"
+			}
+			return checksum
+		}
+
+		log.Printf(
+			"INCONSISTENT: Repo %s has checksum %s on target but checksum %s on reference storage %s",
+			resp.GetRepoRelativePath(),
+			checksumPrint(resp.GetTargetChecksum()),
+			checksumPrint(resp.GetReferenceChecksum()),
+			resp.GetReferenceStorage(),
+		)
+		if resp.GetReplJobId() != 0 {
 			log.Printf(
-				"INCONSISTENT: %s - replication scheduled: #%d",
-				resp.GetRepoRelativePath(),
+				"SCHEDULED: Replication job %d will update repo %s",
 				resp.GetReplJobId(),
+				resp.GetRepoRelativePath(),
 			)
 		}
 	}
+
+	log.Printf("FINISHED: %d repos were checked for consistency", i)
 	return nil
 }
diff --git a/internal/praefect/consistencycheck_test.go b/internal/praefect/consistencycheck_test.go
index dce2bb473..69c923603 100644
--- a/internal/praefect/consistencycheck_test.go
+++ b/internal/praefect/consistencycheck_test.go
@@ -77,11 +77,14 @@ func TestConsistencyCheck(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
-	reposAreConsistent := func() (consistent bool) {
+	disableReconcilliation := true
+
+	requestConsistencyCheck := func() *gitalypb.ConsistencyCheckResponse {
 		stream, err := praefectCli.ConsistencyCheck(ctx, &gitalypb.ConsistencyCheckRequest{
-			VirtualStorage:   virtualStorage.Name,
-			ReferenceStorage: primary.Storage,
-			TargetStorage:    secondary.Storage,
+			VirtualStorage:         virtualStorage.Name,
+			ReferenceStorage:       primary.Storage,
+			TargetStorage:          secondary.Storage,
+			DisableReconcilliation: disableReconcilliation,
 		})
 		require.NoError(t, err)
 
@@ -89,24 +92,28 @@ func TestConsistencyCheck(t *testing.T) {
 		require.Len(t, responses, 1)
 
 		resp := responses[0]
-		require.Equal(t, repo0.RelativePath, resp.RepoRelativePath)
 
-		consistent = resp.TargetChecksum == resp.ReferenceChecksum
-		if !consistent {
-			require.NotZero(t, resp.ReplJobId,
-				"A replication job should be scheduled when inconsistent")
-		}
+		require.Equal(t, repo0.RelativePath, resp.RepoRelativePath)
+		require.Equal(t, primary.Storage, resp.ReferenceStorage)
 
-		return consistent
+		return resp
 	}
 
-	require.True(t, reposAreConsistent(),
+	resp := requestConsistencyCheck()
+	require.Equal(t, resp.ReferenceChecksum, resp.TargetChecksum,
 		"both repos expected to be consistent after initial clone")
+	require.Zero(t, resp.ReplJobId)
 
 	testhelper.MustRunCommand(t, nil, "git", "-C", targetRepoPath, "update-ref", "HEAD", "spooky-stuff")
 
-	require.False(t, reposAreConsistent(),
+	resp = requestConsistencyCheck()
+	require.NotEqual(t, resp.ReferenceChecksum, resp.TargetChecksum,
 		"repos should no longer be consistent after target HEAD changed")
+	require.Zero(t, resp.ReplJobId)
+
+	disableReconcilliation = false
+	resp = requestConsistencyCheck()
+	require.NotZero(t, resp.ReplJobId)
 }
 
 func consumeConsistencyCheckResponses(t *testing.T, stream gitalypb.PraefectInfoService_ConsistencyCheckClient) []*gitalypb.ConsistencyCheckResponse {
diff --git a/internal/praefect/service/info/consistencycheck.go b/internal/praefect/service/info/consistencycheck.go
index 7c071be92..22e5ab264 100644
--- a/internal/praefect/service/info/consistencycheck.go
+++ b/internal/praefect/service/info/consistencycheck.go
@@ -190,22 +190,27 @@ func scheduleReplication(ctx context.Context, csr checksumResult, q Queue, resp
 	return nil
 }
 
-func ensureConsistency(ctx context.Context, checksumResultQ <-chan checksumResult, q Queue, stream gitalypb.PraefectInfoService_ConsistencyCheckServer) error {
-	for csr := range checksumResultQ {
+func ensureConsistency(ctx context.Context, disableReconcile bool, checksumResultQ <-chan checksumResult, q Queue, stream gitalypb.PraefectInfoService_ConsistencyCheckServer) error {
+	for {
+		var csr checksumResult
 		select {
+		case res, ok := <-checksumResultQ:
+			if !ok {
+				return nil
+			}
+			csr = res
 		case <-ctx.Done():
 			return ctx.Err()
-		default:
-			// continue
 		}
 
 		resp := &gitalypb.ConsistencyCheckResponse{
 			RepoRelativePath:  csr.relativePath,
 			ReferenceChecksum: csr.reference,
 			TargetChecksum:    csr.target,
+			ReferenceStorage:  csr.referenceStorage,
 		}
 
-		if csr.reference != csr.target {
+		if csr.reference != csr.target && !disableReconcile {
 			if err := scheduleReplication(ctx, csr, q, resp); err != nil {
 				return err
 			}
@@ -244,7 +249,7 @@ func (s *Server) ConsistencyCheck(req *gitalypb.ConsistencyCheckRequest, stream
 		return checksumRepos(ctx, walkerQ, checksumResultQ, target, reference, req.GetVirtualStorage())
 	})
 	g.Go(func() error {
-		return ensureConsistency(ctx, checksumResultQ, s.queue, stream)
+		return ensureConsistency(ctx, req.GetDisableReconcilliation(), checksumResultQ, s.queue, stream)
 	})
 
 	return g.Wait()
diff --git a/proto/go/gitalypb/praefect.pb.go b/proto/go/gitalypb/praefect.pb.go
index 72716df6c..5f92fae9d 100644
--- a/proto/go/gitalypb/praefect.pb.go
+++ b/proto/go/gitalypb/praefect.pb.go
@@ -264,10 +264,13 @@ type ConsistencyCheckRequest struct {
 	// Optionally provide a reference storage to compare the target storage
 	// against. If a reference storage is omitted, the current primary will be
 	// used.
-	ReferenceStorage     string   `protobuf:"bytes,3,opt,name=reference_storage,json=referenceStorage,proto3" json:"reference_storage,omitempty"`
-	XXX_NoUnkeyedLiteral struct{} `json:"-"`
-	XXX_unrecognized     []byte   `json:"-"`
-	XXX_sizecache        int32    `json:"-"`
+	ReferenceStorage string `protobuf:"bytes,3,opt,name=reference_storage,json=referenceStorage,proto3" json:"reference_storage,omitempty"`
+	// Be default, reconcilliation is enabled. Disabling reconcilliation will
+	// make the request side-effect free.
+	DisableReconcilliation bool     `protobuf:"varint,4,opt,name=disable_reconcilliation,json=disableReconcilliation,proto3" json:"disable_reconcilliation,omitempty"`
+	XXX_NoUnkeyedLiteral   struct{} `json:"-"`
+	XXX_unrecognized       []byte   `json:"-"`
+	XXX_sizecache          int32    `json:"-"`
 }
 
 func (m *ConsistencyCheckRequest) Reset()         { *m = ConsistencyCheckRequest{} }
@@ -316,13 +319,22 @@ func (m *ConsistencyCheckRequest) GetReferenceStorage() string {
 	return ""
 }
 
+func (m *ConsistencyCheckRequest) GetDisableReconcilliation() bool {
+	if m != nil {
+		return m.DisableReconcilliation
+	}
+	return false
+}
+
 type ConsistencyCheckResponse struct {
 	RepoRelativePath  string `protobuf:"bytes,1,opt,name=repo_relative_path,json=repoRelativePath,proto3" json:"repo_relative_path,omitempty"`
 	TargetChecksum    string `protobuf:"bytes,2,opt,name=target_checksum,json=targetChecksum,proto3" json:"target_checksum,omitempty"`
 	ReferenceChecksum string `protobuf:"bytes,3,opt,name=reference_checksum,json=referenceChecksum,proto3" json:"reference_checksum,omitempty"`
 	// If resync was enabled, then each inconsistency will schedule a replication
 	// job. A replication ID is returned to track the corresponding job.
-	ReplJobId            uint64   `protobuf:"varint,4,opt,name=repl_job_id,json=replJobId,proto3" json:"repl_job_id,omitempty"`
+	ReplJobId uint64 `protobuf:"varint,4,opt,name=repl_job_id,json=replJobId,proto3" json:"repl_job_id,omitempty"`
+	// If the reference storage was not specified, reply with the reference used
+	ReferenceStorage     string   `protobuf:"bytes,5,opt,name=reference_storage,json=referenceStorage,proto3" json:"reference_storage,omitempty"`
 	XXX_NoUnkeyedLiteral struct{} `json:"-"`
 	XXX_unrecognized     []byte   `json:"-"`
 	XXX_sizecache        int32    `json:"-"`
@@ -381,6 +393,13 @@ func (m *ConsistencyCheckResponse) GetReplJobId() uint64 {
 	return 0
 }
 
+func (m *ConsistencyCheckResponse) GetReferenceStorage() string {
+	if m != nil {
+		return m.ReferenceStorage
+	}
+	return ""
+}
+
 func init() {
 	proto.RegisterType((*DatalossCheckRequest)(nil), "gitaly.DatalossCheckRequest")
 	proto.RegisterType((*DatalossCheckResponse)(nil), "gitaly.DatalossCheckResponse")
@@ -395,47 +414,49 @@ func init() {
 func init() { proto.RegisterFile("praefect.proto", fileDescriptor_d32bf44842ead735) }
 
 var fileDescriptor_d32bf44842ead735 = []byte{
-	// 626 bytes of a gzipped FileDescriptorProto
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+	// 663 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x9c, 0x54, 0x5d, 0x6e, 0xd3, 0x40,
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+	0x47, 0xfa, 0x18, 0x34, 0x06, 0x00, 0x00,
 }
 
 // Reference imports to suppress errors if they are not otherwise used.
diff --git a/proto/praefect.proto b/proto/praefect.proto
index 3b5b3225f..df4677ada 100644
--- a/proto/praefect.proto
+++ b/proto/praefect.proto
@@ -77,6 +77,9 @@ message ConsistencyCheckRequest {
   // against. If a reference storage is omitted, the current primary will be
   // used.
   string reference_storage = 3;
+  // Be default, reconcilliation is enabled. Disabling reconcilliation will
+  // make the request side-effect free.
+  bool disable_reconcilliation = 4;
 }
 
 message ConsistencyCheckResponse {
@@ -86,4 +89,6 @@ message ConsistencyCheckResponse {
   // If resync was enabled, then each inconsistency will schedule a replication
   // job. A replication ID is returned to track the corresponding job.
   uint64 repl_job_id = 4;
+  // If the reference storage was not specified, reply with the reference used
+  string reference_storage = 5;
 }
diff --git a/ruby/proto/gitaly/praefect_pb.rb b/ruby/proto/gitaly/praefect_pb.rb
index f5c5a7d30..5e418cc97 100644
--- a/ruby/proto/gitaly/praefect_pb.rb
+++ b/ruby/proto/gitaly/praefect_pb.rb
@@ -29,12 +29,14 @@ Google::Protobuf::DescriptorPool.generated_pool.build do
     optional :virtual_storage, :string, 1
     optional :target_storage, :string, 2
     optional :reference_storage, :string, 3
+    optional :disable_reconcilliation, :bool, 4
   end
   add_message "gitaly.ConsistencyCheckResponse" do
     optional :repo_relative_path, :string, 1
     optional :target_checksum, :string, 2
     optional :reference_checksum, :string, 3
     optional :repl_job_id, :uint64, 4
+    optional :reference_storage, :string, 5
   end
 end