consumer.go

Copyright 2020, 2021 Red Hat, 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
main
import
(
"context"
"errors"
"github.com/rs/zerolog/log"
"github.com/RedHatInsights/insights-results-aggregator/broker"
"github.com/RedHatInsights/insights-results-aggregator/conf"
"github.com/RedHatInsights/insights-results-aggregator/consumer"
"github.com/RedHatInsights/insights-results-aggregator/types"
)
var
(
consumerInstance
*
consumer
.
KafkaConsumer
consumerInstanceIsStarting
,
finishConsumerInstanceInitialization
=
context
.
WithCancel
(
context
.
Background
(
)
)
)

startConsumer function starts the consumer or returns an error in case of any error. When consumer is started properly, nil is returned instead.

func
startConsumer
(
brokerConf
broker
.
Configuration
)
error
{
defer
finishConsumerInstanceInitialization
(
)

right now just the OCP recommendation storage is handled by consumer

	
ocpRecommendationsStorage
,
dvoRecommendationStorage
,
err
:=
createStorage
(
)
if
err
!=
nil
{
return
err
}
defer
closeStorage
(
ocpRecommendationsStorage
)
defer
closeStorage
(
dvoRecommendationStorage
)

when DVO consumer will be made, it will need to use DVO storage (see line that calls createStorage())

	
if
conf
.
GetStorageBackendConfiguration
(
)
.
Use
==
types
.
OCPRecommendationsStorage
{
consumerInstance
,
err
=
consumer
.
NewOCPRulesConsumer
(
brokerConf
,
ocpRecommendationsStorage
)
if
err
!=
nil
{
log
.
Error
(
)
.
Err
(
err
)
.
Msg
(
"Broker initialization error"
)
return
err
}
}
else
if
conf
.
GetStorageBackendConfiguration
(
)
.
Use
==
types
.
DVORecommendationsStorage
{
consumerInstance
,
err
=
consumer
.
NewDVORulesConsumer
(
brokerConf
,
dvoRecommendationStorage
)
if
err
!=
nil
{
log
.
Error
(
)
.
Err
(
err
)
.
Msg
(
"Broker initialization error"
)
return
err
}
}
else
{
log
.
Error
(
)
.
Msg
(
"No backend storage or incompatible one selected. Exitting"
)
return
errors
.
New
(
"no backend storage or incompatible selected"
)
}
finishConsumerInstanceInitialization
(
)
consumerInstance
.
Serve
(
)
return
nil
}

stopConsumer function tries to stop the consumer. If consumer is not started or if it is not possible to stop it properly, error value is returned.

func
stopConsumer
(
)
error
{
waitForConsumerToStartOrFail
(
)
if
consumerInstance
==
nil
{
return
nil
}
err
:=
consumerInstance
.
Close
(
)
if
err
!=
nil
{
log
.
Error
(
)
.
Err
(
err
)
.
Msg
(
"Consumer stop error"
)
return
err
}
return
nil
}

waitForConsumerToStartOrFail function perform synchronization with the consumer goroutine via shared channel.

func
waitForConsumerToStartOrFail
(
)
{
log
.
Info
(
)
.
Msg
(
"waiting for consumer to start"
)
<-
consumerInstanceIsStarting
.
Done
(
)
}