forked from jaegertracing/jaeger
/
best_eta.go
135 lines (120 loc) · 3.68 KB
/
best_eta.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
// 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 frontend
import (
"context"
"errors"
"math"
"sync"
"time"
"github.com/opentracing/opentracing-go"
"go.uber.org/zap"
"github.com/jaegertracing/jaeger/examples/hotrod/pkg/log"
"github.com/jaegertracing/jaeger/examples/hotrod/pkg/pool"
"github.com/jaegertracing/jaeger/examples/hotrod/services/config"
"github.com/jaegertracing/jaeger/examples/hotrod/services/customer"
"github.com/jaegertracing/jaeger/examples/hotrod/services/driver"
"github.com/jaegertracing/jaeger/examples/hotrod/services/route"
)
type bestETA struct {
customer customer.Interface
driver driver.Interface
route route.Interface
pool *pool.Pool
logger log.Factory
}
// Response contains ETA for a trip.
type Response struct {
Driver string
ETA time.Duration
}
func newBestETA(tracer opentracing.Tracer, logger log.Factory) *bestETA {
return &bestETA{
customer: customer.NewClient(
tracer,
logger.With(zap.String("component", "customer_client")),
),
driver: driver.NewClient(
tracer,
logger.With(zap.String("component", "driver_client")),
),
route: route.NewClient(
tracer,
logger.With(zap.String("component", "route_client")),
),
pool: pool.New(config.RouteWorkerPoolSize),
logger: logger,
}
}
func (eta *bestETA) Get(ctx context.Context, customerID string) (*Response, error) {
customer, err := eta.customer.Get(ctx, customerID)
if err != nil {
return nil, err
}
eta.logger.For(ctx).Info("Found customer", zap.Any("customer", customer))
if span := opentracing.SpanFromContext(ctx); span != nil {
span.SetBaggageItem("customer", customer.Name)
}
drivers, err := eta.driver.FindNearest(ctx, customer.Location)
if err != nil {
return nil, err
}
eta.logger.For(ctx).Info("Found drivers", zap.Any("drivers", drivers))
results := eta.getRoutes(ctx, customer, drivers)
eta.logger.For(ctx).Info("Found routes", zap.Any("routes", results))
resp := &Response{ETA: math.MaxInt64}
for _, result := range results {
if result.err != nil {
return nil, err
}
if result.route.ETA < resp.ETA {
resp.ETA = result.route.ETA
resp.Driver = result.driver
}
}
if resp.Driver == "" {
return nil, errors.New("No routes found")
}
eta.logger.For(ctx).Info("Dispatch successful", zap.String("driver", resp.Driver), zap.String("eta", resp.ETA.String()))
return resp, nil
}
type routeResult struct {
driver string
route *route.Route
err error
}
// getRoutes calls Route service for each (customer, driver) pair
func (eta *bestETA) getRoutes(ctx context.Context, customer *customer.Customer, drivers []driver.Driver) []routeResult {
results := make([]routeResult, 0, len(drivers))
wg := sync.WaitGroup{}
routesLock := sync.Mutex{}
for _, dd := range drivers {
wg.Add(1)
driver := dd // capture loop var
// Use worker pool to (potentially) execute requests in parallel
eta.pool.Execute(func() {
route, err := eta.route.FindRoute(ctx, driver.Location, customer.Location)
routesLock.Lock()
results = append(results, routeResult{
driver: driver.DriverID,
route: route,
err: err,
})
routesLock.Unlock()
wg.Done()
})
}
wg.Wait()
return results
}