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// Copyright (c) 2019 The Jaeger Authors.
// Copyright (c) 2017 Uber Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package driver
import (
"context"
"errors"
"fmt"
"math/rand"
"sync"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/codes"
"go.opentelemetry.io/otel/trace"
"go.uber.org/zap"
"github.com/jaegertracing/jaeger/examples/hotrod/pkg/delay"
"github.com/jaegertracing/jaeger/examples/hotrod/pkg/log"
"github.com/jaegertracing/jaeger/examples/hotrod/pkg/tracing"
"github.com/jaegertracing/jaeger/examples/hotrod/services/config"
"github.com/jaegertracing/jaeger/pkg/metrics"
)
// Redis is a simulator of remote Redis cache
type Redis struct {
tracer trace.Tracer // simulate redis as a separate process
logger log.Factory
errorSimulator
}
func newRedis(otelExporter string, metricsFactory metrics.Factory, logger log.Factory) *Redis {
tp := tracing.InitOTEL("redis-manual", otelExporter, metricsFactory, logger)
return &Redis{
tracer: tp.Tracer("redis-manual"),
logger: logger,
}
}
// FindDriverIDs finds IDs of drivers who are near the location.
func (r *Redis) FindDriverIDs(ctx context.Context, location string) []string {
ctx, span := r.tracer.Start(ctx, "FindDriverIDs", trace.WithSpanKind(trace.SpanKindClient))
span.SetAttributes(attribute.Key("param.driver.location").String(location))
defer span.End()
// simulate RPC delay
delay.Sleep(config.RedisFindDelay, config.RedisFindDelayStdDev)
drivers := make([]string, 10)
for i := range drivers {
// #nosec
drivers[i] = fmt.Sprintf("T7%05dC", rand.Int()%100000)
}
r.logger.For(ctx).Info("Found drivers", zap.Strings("drivers", drivers))
return drivers
}
// GetDriver returns driver and the current car location
func (r *Redis) GetDriver(ctx context.Context, driverID string) (Driver, error) {
ctx, span := r.tracer.Start(ctx, "GetDriver", trace.WithSpanKind(trace.SpanKindClient))
span.SetAttributes(attribute.Key("param.driverID").String(driverID))
defer span.End()
// simulate RPC delay
delay.Sleep(config.RedisGetDelay, config.RedisGetDelayStdDev)
if err := r.checkError(); err != nil {
span.RecordError(err)
span.SetStatus(codes.Error, "An error occurred")
r.logger.For(ctx).Error("redis timeout", zap.String("driver_id", driverID), zap.Error(err))
return Driver{}, err
}
r.logger.For(ctx).Info("Got driver's ID", zap.String("driverID", driverID))
// #nosec
return Driver{
DriverID: driverID,
Location: fmt.Sprintf("%d,%d", rand.Int()%1000, rand.Int()%1000),
}, nil
}
var errTimeout = errors.New("redis timeout")
type errorSimulator struct {
sync.Mutex
countTillError int
}
func (es *errorSimulator) checkError() error {
es.Lock()
es.countTillError--
if es.countTillError > 0 {
es.Unlock()
return nil
}
es.countTillError = 5
es.Unlock()
delay.Sleep(2*config.RedisGetDelay, 0) // add more delay for "timeout"
return errTimeout
}