sql: add new system table for locality locations

Adds a new table, `system.locations`, which maps a string locality
(i.e. "city=New York City") to geographic coordinates, specified as
a latitude, longitude decimal pair, specified in degrees.

A new admin API call returns the contents of the table, for use from
the admin UI.

Fixes cockroachdb#19532

Release note (ui): A system table to allow operators to designate
geographic coordinates for any locality. For use with frontend
cluster visualization.

pkg/cli/cli_test.go

@@ -396,7 +396,7 @@ func Example_ranges() {
 	//	0: node-id=1 store-id=1
 	///System/"tse"-"ranges3" [6]
 	//	0: node-id=1 store-id=1
-	//"ranges3"-/Table/SystemConfigSpan/Start [18]
+	//"ranges3"-/Table/SystemConfigSpan/Start [19]
 	//	0: node-id=1 store-id=1
 	///Table/SystemConfigSpan/Start-/Table/11 [7]
 	//	0: node-id=1 store-id=1
@@ -418,9 +418,11 @@ func Example_ranges() {
 	//	0: node-id=1 store-id=1
 	///Table/19-/Table/20 [16]
 	//	0: node-id=1 store-id=1
-	///Table/20-/Max [17]
+	///Table/20-/Table/21 [17]
 	//	0: node-id=1 store-id=1
-	//18 result(s)
+	///Table/21-/Max [18]
+	//	0: node-id=1 store-id=1
+	//19 result(s)
 
 }
 
@@ -1862,11 +1864,13 @@ writing ` + os.DevNull + `
   debug/nodes/1/ranges/15
   debug/nodes/1/ranges/16
   debug/nodes/1/ranges/17
+  debug/nodes/1/ranges/18
   debug/schema/system@details
   debug/schema/system/descriptor
   debug/schema/system/eventlog
   debug/schema/system/jobs
   debug/schema/system/lease
+  debug/schema/system/locations
   debug/schema/system/namespace
   debug/schema/system/rangelog
   debug/schema/system/settings

pkg/config/system_test.go

@@ -392,6 +392,7 @@ func TestGetZoneConfigForKey(t *testing.T) {
 		{tkey(keys.ZonesTableID), keys.SystemDatabaseID},
 		{tkey(keys.LeaseTableID), keys.SystemDatabaseID},
 		{tkey(keys.JobsTableID), keys.SystemDatabaseID},
+		{tkey(keys.LocationsTableID), keys.SystemDatabaseID},
 		{tkey(keys.MaxReservedDescID + 1), keys.MaxReservedDescID + 1},
 		{tkey(keys.MaxReservedDescID + 23), keys.MaxReservedDescID + 23},
 		{roachpb.RKeyMax, keys.RootNamespaceID},

pkg/keys/constants.go

@@ -315,4 +315,5 @@ const (
 	TimeseriesRangesID     = 18
 	WebSessionsTableID     = 19
 	TableStatisticsTableID = 20
+	LocationsTableID       = 21
 )

pkg/server/admin.go

@@ -31,6 +31,7 @@ import (
 
 	"encoding/json"
 
+	"github.com/cockroachdb/apd"
 	"github.com/cockroachdb/cockroach/pkg/base"
 	"github.com/cockroachdb/cockroach/pkg/config"
 	"github.com/cockroachdb/cockroach/pkg/internal/client"
@@ -1088,6 +1089,43 @@ func (s *adminServer) Jobs(
 	return &resp, nil
 }
 
+func (s *adminServer) Locations(
+	ctx context.Context, req *serverpb.LocationsRequest,
+) (*serverpb.LocationsResponse, error) {
+	args := sql.SessionArgs{User: s.getUser(req)}
+	ctx, session := s.NewContextAndSessionForRPC(ctx, args)
+	defer session.Finish(s.server.sqlExecutor)
+
+	q := makeSQLQuery()
+	q.Append(`SELECT "localityKey", "localityValue", latitude, longitude FROM system.locations`)
+	r, err := s.server.sqlExecutor.ExecuteStatementsBuffered(session, q.String(), nil, 1)
+	if err != nil {
+		return nil, s.serverError(err)
+	}
+	defer r.Close(ctx)
+
+	scanner := makeResultScanner(r.ResultList[0].Columns)
+	resp := serverpb.LocationsResponse{
+		Locations: make([]serverpb.LocationsResponse_Location, r.ResultList[0].Rows.Len()),
+	}
+	for i := 0; i < len(resp.Locations); i++ {
+		loc := &resp.Locations[i]
+		lat, lon := new(apd.Decimal), new(apd.Decimal)
+		if err := scanner.ScanAll(
+			r.ResultList[0].Rows.At(i), &loc.LocalityKey, &loc.LocalityValue, lat, lon); err != nil {
+			return nil, s.serverError(err)
+		}
+		if loc.Latitude, err = lat.Float64(); err != nil {
+			return nil, s.serverError(err)
+		}
+		if loc.Longitude, err = lon.Float64(); err != nil {
+			return nil, s.serverError(err)
+		}
+	}
+
+	return &resp, nil
+}
+
 // QueryPlan returns a JSON representation of a distsql physical query
 // plan.
 func (s *adminServer) QueryPlan(
@@ -1440,6 +1478,13 @@ func (rs resultScanner) ScanIndex(row tree.Datums, index int, dst interface{}) e
 		// Yes, this copies, but this probably isn't in the critical path.
 		*d = []byte(*s)
 
+	case *apd.Decimal:
+		s, ok := src.(*tree.DDecimal)
+		if !ok {
+			return errors.Errorf("source type assertion failed")
+		}
+		*d = s.Decimal
+
 	default:
 		return errors.Errorf("unimplemented type for scanCol: %T", dst)
 	}

pkg/server/admin_test.go

@@ -1182,6 +1182,46 @@ func TestAdminAPIJobs(t *testing.T) {
 	}
 }
 
+func TestAdminAPILocations(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+
+	s, conn, _ := serverutils.StartServer(t, base.TestServerArgs{})
+	defer s.Stopper().Stop(context.TODO())
+	sqlDB := sqlutils.MakeSQLRunner(conn)
+
+	testLocations := []struct {
+		localityKey   string
+		localityValue string
+		latitude      float64
+		longitude     float64
+	}{
+		{"city", "Des Moines", 41.60054, -93.60911},
+		{"city", "New York City", 40.71427, -74.00597},
+		{"city", "Seattle", 47.60621, -122.33207},
+	}
+	for _, loc := range testLocations {
+		sqlDB.Exec(t,
+			`INSERT INTO system.locations ("localityKey", "localityValue", latitude, longitude) VALUES ($1, $2, $3, $4)`,
+			loc.localityKey, loc.localityValue, loc.latitude, loc.longitude,
+		)
+	}
+	var res serverpb.LocationsResponse
+	if err := getAdminJSONProto(s, "locations", &res); err != nil {
+		t.Fatal(err)
+	}
+	for i, loc := range testLocations {
+		expLoc := serverpb.LocationsResponse_Location{
+			LocalityKey:   loc.localityKey,
+			LocalityValue: loc.localityValue,
+			Latitude:      loc.latitude,
+			Longitude:     loc.longitude,
+		}
+		if !reflect.DeepEqual(res.Locations[i], expLoc) {
+			t.Errorf("%d: expected location %v, but got %v", i, expLoc, res.Locations[i])
+		}
+	}
+}
+
 func TestAdminAPIQueryPlan(t *testing.T) {
 	defer leaktest.AfterTest(t)()