github.com/kaleido-io/firefly@v0.0.0-20210622132723-8b4b6aacb971/internal/events/offset_calc.go (about)

     1  // Copyright © 2021 Kaleido, Inc.
     2  //
     3  // SPDX-License-Identifier: Apache-2.0
     4  //
     5  // Licensed under the Apache License, Version 2.0 (the "License");
     6  // you may not use this file except in compliance with the License.
     7  // You may obtain a copy of the License at
     8  //
     9  //     http://www.apache.org/licenses/LICENSE-2.0
    10  //
    11  // Unless required by applicable law or agreed to in writing, software
    12  // distributed under the License is distributed on an "AS IS" BASIS,
    13  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14  // See the License for the specific language governing permissions and
    15  // limitations under the License.
    16  
    17  package events
    18  
    19  import (
    20  	"context"
    21  	"strconv"
    22  
    23  	"github.com/kaleido-io/firefly/internal/i18n"
    24  	"github.com/kaleido-io/firefly/internal/log"
    25  	"github.com/kaleido-io/firefly/pkg/database"
    26  	"github.com/kaleido-io/firefly/pkg/fftypes"
    27  )
    28  
    29  func calcFirstOffset(ctx context.Context, di database.Plugin, pfe *fftypes.SubOptsFirstEvent) (firstOffset int64, err error) {
    30  	firstEvent := fftypes.SubOptsFirstEventNewest
    31  	if pfe != nil {
    32  		firstEvent = *pfe
    33  	}
    34  	firstOffset = -1
    35  	var useNewest bool
    36  	switch firstEvent {
    37  	case "", fftypes.SubOptsFirstEventNewest:
    38  		useNewest = true
    39  	case fftypes.SubOptsFirstEventOldest:
    40  		useNewest = false
    41  	default:
    42  		specificSequence, err := strconv.ParseInt(string(firstEvent), 10, 64)
    43  		if err != nil {
    44  			return -1, i18n.WrapError(ctx, err, i18n.MsgInvalidFirstEvent, firstEvent)
    45  		}
    46  		if specificSequence < -1 {
    47  			return -1, i18n.NewError(ctx, i18n.MsgNumberMustBeGreaterEqual, -1)
    48  		}
    49  		firstOffset = specificSequence
    50  		useNewest = false
    51  	}
    52  	if useNewest {
    53  		f := database.EventQueryFactory.NewFilter(ctx).And().Sort("sequence").Descending().Limit(1)
    54  		newestEvents, err := di.GetEvents(ctx, f)
    55  		if err != nil {
    56  			return firstOffset, err
    57  		}
    58  		if len(newestEvents) > 0 {
    59  			return newestEvents[0].Sequence, nil
    60  		}
    61  	}
    62  	log.L(ctx).Debugf("Event poller initial offest: %d (newest=%t)", firstOffset, useNewest)
    63  	return firstOffset, err
    64  }