services/horizon: Remove global ledger state (#3216)

horizon/ledger.State is a global variable. This is a bad pattern and caused some issues (see #3143). We should make the state local to horizon.App and pass a pointer to it to other parts of the system that need it.

services/horizon/internal/actions/account.go

@@ -8,6 +8,7 @@ import (
 	protocol "github.com/stellar/go/protocols/horizon"
 	horizonContext "github.com/stellar/go/services/horizon/internal/context"
 	"github.com/stellar/go/services/horizon/internal/db2/history"
+	"github.com/stellar/go/services/horizon/internal/ledger"
 	"github.com/stellar/go/services/horizon/internal/resourceadapter"
 	"github.com/stellar/go/support/errors"
 	"github.com/stellar/go/support/render/hal"
@@ -118,7 +119,9 @@ func (q AccountsQuery) Asset() *xdr.Asset {
 }
 
 // GetAccountsHandler is the action handler for the /accounts endpoint
-type GetAccountsHandler struct{}
+type GetAccountsHandler struct {
+	LedgerState *ledger.State
+}
 
 // GetResourcePage returns a page containing the account records that have
 // `signer` as a signer or have a trustline to the given asset.
@@ -127,7 +130,7 @@ func (handler GetAccountsHandler) GetResourcePage(
 	r *http.Request,
 ) ([]hal.Pageable, error) {
 	ctx := r.Context()
-	pq, err := GetPageQuery(r, DisableCursorValidation)
+	pq, err := GetPageQuery(handler.LedgerState, r, DisableCursorValidation)
 	if err != nil {
 		return nil, err
 	}

services/horizon/internal/actions/asset.go

@@ -9,6 +9,7 @@ import (
 	"github.com/stellar/go/services/horizon/internal/context"
 	"github.com/stellar/go/services/horizon/internal/db2"
 	"github.com/stellar/go/services/horizon/internal/db2/history"
+	"github.com/stellar/go/services/horizon/internal/ledger"
 	"github.com/stellar/go/services/horizon/internal/resourceadapter"
 	"github.com/stellar/go/support/errors"
 	"github.com/stellar/go/support/render/hal"
@@ -18,6 +19,7 @@ import (
 
 // AssetStatsHandler is the action handler for the /asset endpoint
 type AssetStatsHandler struct {
+	LedgerState *ledger.State
 }
 
 func (handler AssetStatsHandler) validateAssetParams(code, issuer string, pq db2.PageQuery) error {
@@ -123,7 +125,7 @@ func (handler AssetStatsHandler) GetResourcePage(
 		return nil, err
 	}
 
-	pq, err := GetPageQuery(r, DisableCursorValidation)
+	pq, err := GetPageQuery(handler.LedgerState, r, DisableCursorValidation)
 	if err != nil {
 		return nil, err
 	}

services/horizon/internal/actions/claimable_balance.go

@@ -10,6 +10,7 @@ import (
 	protocol "github.com/stellar/go/protocols/horizon"
 	horizonContext "github.com/stellar/go/services/horizon/internal/context"
 	"github.com/stellar/go/services/horizon/internal/db2/history"
+	"github.com/stellar/go/services/horizon/internal/ledger"
 	"github.com/stellar/go/services/horizon/internal/resourceadapter"
 	"github.com/stellar/go/support/errors"
 	"github.com/stellar/go/support/render/hal"
@@ -129,6 +130,7 @@ func (q ClaimableBalancesQuery) URITemplate() string {
 }
 
 type GetClaimableBalancesHandler struct {
+	LedgerState *ledger.State
 }
 
 // GetResourcePage returns a page of claimable balances.
@@ -143,7 +145,7 @@ func (handler GetClaimableBalancesHandler) GetResourcePage(
 		return nil, err
 	}
 
-	pq, err := GetPageQuery(r, DisableCursorValidation)
+	pq, err := GetPageQuery(handler.LedgerState, r, DisableCursorValidation)
 	if err != nil {
 		return nil, err
 	}

services/horizon/internal/actions/effects.go

@@ -6,6 +6,7 @@ import (
 	"github.com/stellar/go/services/horizon/internal/context"
 	"github.com/stellar/go/services/horizon/internal/db2"
 	"github.com/stellar/go/services/horizon/internal/db2/history"
+	"github.com/stellar/go/services/horizon/internal/ledger"
 	"github.com/stellar/go/services/horizon/internal/resourceadapter"
 	"github.com/stellar/go/support/errors"
 	"github.com/stellar/go/support/render/hal"
@@ -42,15 +43,17 @@ func (qp EffectsQuery) Validate() error {
 	return nil
 }
 
-type GetEffectsHandler struct{}
+type GetEffectsHandler struct {
+	LedgerState *ledger.State
+}
 
 func (handler GetEffectsHandler) GetResourcePage(w HeaderWriter, r *http.Request) ([]hal.Pageable, error) {
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(handler.LedgerState, r)
 	if err != nil {
 		return nil, err
 	}
 
-	err = validateCursorWithinHistory(pq)
+	err = validateCursorWithinHistory(handler.LedgerState, pq)
 	if err != nil {
 		return nil, err
 	}

services/horizon/internal/actions/helpers.go

@@ -58,15 +58,15 @@ func SetLastLedgerHeader(w HeaderWriter, lastLedger uint32) {
 
 // getCursor retrieves a string from either the URLParams, form or query string.
 // This method uses the priority (URLParams, Form, Query).
-func getCursor(r *http.Request, name string) (string, error) {
+func getCursor(ledgerState *ledger.State, r *http.Request, name string) (string, error) {
 	cursor, err := getString(r, name)
 
 	if err != nil {
 		return "", err
 	}
 
 	if cursor == "now" {
-		tid := toid.AfterLedger(ledger.CurrentState().HistoryLatest)
+		tid := toid.AfterLedger(ledgerState.CurrentStatus().HistoryLatest)
 		cursor = tid.String()
 	}
 
@@ -180,15 +180,15 @@ func getLimit(r *http.Request, name string, def uint64, max uint64) (uint64, err
 
 // GetPageQuery is a helper that returns a new db.PageQuery struct initialized
 // using the results from a call to GetPagingParams()
-func GetPageQuery(r *http.Request, opts ...Opt) (db2.PageQuery, error) {
+func GetPageQuery(ledgerState *ledger.State, r *http.Request, opts ...Opt) (db2.PageQuery, error) {
 	disableCursorValidation := false
 	for _, opt := range opts {
 		if opt == DisableCursorValidation {
 			disableCursorValidation = true
 		}
 	}
 
-	cursor, err := getCursor(r, ParamCursor)
+	cursor, err := getCursor(ledgerState, r, ParamCursor)
 	if err != nil {
 		return db2.PageQuery{}, err
 	}
@@ -535,7 +535,7 @@ func validateAssetParams(aType, code, issuer, prefix string) error {
 // validateCursorWithinHistory compares the requested page of data against the
 // ledger state of the history database.  In the event that the cursor is
 // guaranteed to return no results, we return a 410 GONE http response.
-func validateCursorWithinHistory(pq db2.PageQuery) error {
+func validateCursorWithinHistory(ledgerState *ledger.State, pq db2.PageQuery) error {
 	// an ascending query should never return a gone response:  An ascending query
 	// prior to known history should return results at the beginning of history,
 	// and an ascending query beyond the end of history should not error out but
@@ -560,7 +560,7 @@ func validateCursorWithinHistory(pq db2.PageQuery) error {
 		return problem.MakeInvalidFieldProblem("cursor", errors.New("invalid value"))
 	}
 
-	elder := toid.New(ledger.CurrentState().HistoryElder, 0, 0)
+	elder := toid.New(ledgerState.CurrentStatus().HistoryElder, 0, 0)
 
 	if cursor <= elder.ToInt64() {
 		return &hProblem.BeforeHistory

services/horizon/internal/actions/helpers_test.go

@@ -66,18 +66,19 @@ func TestGetCursor(t *testing.T) {
 	tt := test.Start(t)
 	defer tt.Finish()
 
+	ledgerState := &ledger.State{}
 	// now uses the ledger state
 	r := makeTestActionRequest("/?cursor=now", nil)
-	cursor, err := getCursor(r, "cursor")
+	cursor, err := getCursor(ledgerState, r, "cursor")
 	if tt.Assert.NoError(err) {
-		expected := toid.AfterLedger(ledger.CurrentState().HistoryLatest).String()
+		expected := toid.AfterLedger(ledgerState.CurrentStatus().HistoryLatest).String()
 		tt.Assert.Equal(expected, cursor)
 	}
 
 	//Last-Event-ID overrides cursor
 	r = makeFooBarTestActionRequest()
 	r.Header.Set("Last-Event-ID", "from_header")
-	cursor, err = getCursor(r, "cursor")
+	cursor, err = getCursor(ledgerState, r, "cursor")
 	if tt.Assert.NoError(err) {
 		tt.Assert.Equal("from_header", cursor)
 	}
@@ -135,7 +136,7 @@ func TestValidateCursorWithinHistory(t *testing.T) {
 		t.Run(fmt.Sprintf("cursor: %s", tc.cursor), func(t *testing.T) {
 			pq, err := db2.NewPageQuery(tc.cursor, false, tc.order, 10)
 			tt.NoError(err)
-			err = validateCursorWithinHistory(pq)
+			err = validateCursorWithinHistory(&ledger.State{}, pq)
 
 			if tc.valid {
 				tt.NoError(err)
@@ -238,9 +239,10 @@ func TestActionGetPageQuery(t *testing.T) {
 	tt := test.Start(t)
 	defer tt.Finish()
 	r := makeFooBarTestActionRequest()
+	ledgerState := &ledger.State{}
 
 	// happy path
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(ledgerState, r)
 	tt.Assert.NoError(err)
 	tt.Assert.Equal("123456", pq.Cursor)
 	tt.Assert.Equal(uint64(2), pq.Limit)
@@ -250,23 +252,24 @@ func TestActionGetPageQuery(t *testing.T) {
 	r = makeTestActionRequest("/?limit=foo", nil)
 	_, err = getLimit(r, "limit", 1, 200)
 	tt.Assert.Error(err)
-	_, err = GetPageQuery(r)
+	_, err = GetPageQuery(ledgerState, r)
 	tt.Assert.Error(err)
 
 	// regression: https://github.com/stellar/go/services/horizon/internal/issues/372
 	// (limit of 0 turns into 10)
 	makeTestActionRequest("/?limit=0", nil)
-	_, err = GetPageQuery(r)
+	_, err = GetPageQuery(ledgerState, r)
 	tt.Assert.Error(err)
 }
 
 func TestGetPageQuery(t *testing.T) {
 	tt := test.Start(t)
 	defer tt.Finish()
 	r := makeFooBarTestActionRequest()
+	ledgerState := &ledger.State{}
 
 	// happy path
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(ledgerState, r)
 	tt.Assert.NoError(err)
 	tt.Assert.Equal("123456", pq.Cursor)
 	tt.Assert.Equal(uint64(2), pq.Limit)
@@ -276,13 +279,13 @@ func TestGetPageQuery(t *testing.T) {
 	r = makeTestActionRequest("/?limit=foo", nil)
 	_, err = getLimit(r, "limit", 1, 200)
 	tt.Assert.Error(err)
-	_, err = GetPageQuery(r)
+	_, err = GetPageQuery(ledgerState, r)
 	tt.Assert.Error(err)
 
 	// regression: https://github.com/stellar/go/services/horizon/internal/issues/372
 	// (limit of 0 turns into 10)
 	r = makeTestActionRequest("/?limit=0", nil)
-	_, err = GetPageQuery(r)
+	_, err = GetPageQuery(ledgerState, r)
 	tt.Assert.Error(err)
 }
 

services/horizon/internal/actions/ledger.go

@@ -12,15 +12,17 @@ import (
 	"github.com/stellar/go/support/render/hal"
 )
 
-type GetLedgersHandler struct{}
+type GetLedgersHandler struct {
+	LedgerState *ledger.State
+}
 
 func (handler GetLedgersHandler) GetResourcePage(w HeaderWriter, r *http.Request) ([]hal.Pageable, error) {
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(handler.LedgerState, r)
 	if err != nil {
 		return nil, err
 	}
 
-	err = validateCursorWithinHistory(pq)
+	err = validateCursorWithinHistory(handler.LedgerState, pq)
 	if err != nil {
 		return nil, err
 	}
@@ -53,15 +55,17 @@ type LedgerByIDQuery struct {
 	LedgerID uint32 `schema:"ledger_id" valid:"-"`
 }
 
-type GetLedgerByIDHandler struct{}
+type GetLedgerByIDHandler struct {
+	LedgerState *ledger.State
+}
 
 func (handler GetLedgerByIDHandler) GetResource(w HeaderWriter, r *http.Request) (interface{}, error) {
 	qp := LedgerByIDQuery{}
 	err := getParams(&qp, r)
 	if err != nil {
 		return nil, err
 	}
-	if int32(qp.LedgerID) < ledger.CurrentState().HistoryElder {
+	if int32(qp.LedgerID) < handler.LedgerState.CurrentStatus().HistoryElder {
 		return nil, problem.BeforeHistory
 	}
 	historyQ, err := context.HistoryQFromRequest(r)

services/horizon/internal/actions/offer.go

@@ -7,6 +7,7 @@ import (
 	"github.com/stellar/go/protocols/horizon"
 	horizonContext "github.com/stellar/go/services/horizon/internal/context"
 	"github.com/stellar/go/services/horizon/internal/db2/history"
+	"github.com/stellar/go/services/horizon/internal/ledger"
 	"github.com/stellar/go/services/horizon/internal/resourceadapter"
 	"github.com/stellar/go/support/errors"
 	"github.com/stellar/go/support/render/hal"
@@ -75,6 +76,7 @@ func (q OffersQuery) Validate() error {
 
 // GetOffersHandler is the action handler for the /offers endpoint
 type GetOffersHandler struct {
+	LedgerState *ledger.State
 }
 
 // GetResourcePage returns a page of offers.
@@ -89,7 +91,7 @@ func (handler GetOffersHandler) GetResourcePage(
 		return nil, err
 	}
 
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(handler.LedgerState, r)
 	if err != nil {
 		return nil, err
 	}
@@ -132,10 +134,11 @@ type AccountOffersQuery struct {
 // GetAccountOffersHandler is the action handler for the
 // `/accounts/{account_id}/offers` endpoint when using experimental ingestion.
 type GetAccountOffersHandler struct {
+	LedgerState *ledger.State
 }
 
 func (handler GetAccountOffersHandler) parseOffersQuery(r *http.Request) (history.OffersQuery, error) {
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(handler.LedgerState, r)
 	if err != nil {
 		return history.OffersQuery{}, err
 	}

services/horizon/internal/actions/operation.go

@@ -59,19 +59,20 @@ func (qp OperationsQuery) Validate() error {
 
 // GetOperationsHandler is the action handler for all end-points returning a list of operations.
 type GetOperationsHandler struct {
+	LedgerState  *ledger.State
 	OnlyPayments bool
 }
 
 // GetResourcePage returns a page of operations.
 func (handler GetOperationsHandler) GetResourcePage(w HeaderWriter, r *http.Request) ([]hal.Pageable, error) {
 	ctx := r.Context()
 
-	pq, err := GetPageQuery(r)
+	pq, err := GetPageQuery(handler.LedgerState, r)
 	if err != nil {
 		return nil, err
 	}
 
-	err = validateCursorWithinHistory(pq)
+	err = validateCursorWithinHistory(handler.LedgerState, pq)
 	if err != nil {
 		return nil, err
 	}
@@ -121,18 +122,21 @@ func (handler GetOperationsHandler) GetResourcePage(w HeaderWriter, r *http.Requ
 }
 
 // GetOperationByIDHandler is the action handler for all end-points returning a list of operations.
-type GetOperationByIDHandler struct{}
+type GetOperationByIDHandler struct {
+	LedgerState *ledger.State
+}
 
 // OperationQuery query struct for operation/id end-point
 type OperationQuery struct {
-	Joinable `valid:"optional"`
-	ID       uint64 `schema:"id" valid:"-"`
+	LedgerState *ledger.State `valid:"-"`
+	Joinable    `valid:"optional"`
+	ID          uint64 `schema:"id" valid:"-"`
 }
 
 // Validate runs extra validations on query parameters
 func (qp OperationQuery) Validate() error {
 	parsed := toid.Parse(int64(qp.ID))
-	if parsed.LedgerSequence < ledger.CurrentState().HistoryElder {
+	if parsed.LedgerSequence < qp.LedgerState.CurrentStatus().HistoryElder {
 		return problem.BeforeHistory
 	}
 	return nil
@@ -141,7 +145,9 @@ func (qp OperationQuery) Validate() error {
 // GetResource returns an operation page.
 func (handler GetOperationByIDHandler) GetResource(w HeaderWriter, r *http.Request) (interface{}, error) {
 	ctx := r.Context()
-	qp := OperationQuery{}
+	qp := OperationQuery{
+		LedgerState: handler.LedgerState,
+	}
 	err := getParams(&qp, r)
 	if err != nil {
 		return nil, err