traefik/traefik: pkg/provider/ecs/ecs.go; 128 LoC

Found a possible issue in [traefik/traefik](https://www.github.com/traefik/traefik) at [pkg/provider/ecs/ecs.go](https://github.com/traefik/traefik/blob/a3327c4430cf4a2cb35216776c2c9843281dec00/pkg/provider/ecs/ecs.go#L240-L367)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to c was used in a composite literal at line 242

[Click here to see the code in its original context.](https://github.com/traefik/traefik/blob/a3327c4430cf4a2cb35216776c2c9843281dec00/pkg/provider/ecs/ecs.go#L240-L367)

Click here to show the 128 line(s) of Go which triggered the analyzer.

```go
for _, c := range clusters {
input := &ecs.ListTasksInput{
Cluster: &c,
DesiredStatus: aws.String(ecs.DesiredStatusRunning),
}

tasks := make(map[string]*ecs.Task)
err := client.ecs.ListTasksPagesWithContext(ctx, input, func(page *ecs.ListTasksOutput, lastPage bool) bool {
if len(page.TaskArns) > 0 {
resp, err := client.ecs.DescribeTasksWithContext(ctx, &ecs.DescribeTasksInput{
Tasks: page.TaskArns,
Cluster: &c,
})
if err != nil {
logger.Errorf("Unable to describe tasks for %v", page.TaskArns)
} else {
for _, t := range resp.Tasks {
if aws.StringValue(t.LastStatus) == ecs.DesiredStatusRunning {
tasks[aws.StringValue(t.TaskArn)] = t
}
}
}
}
return !lastPage
})
if err != nil {
logger.Error("Unable to list tasks")
return nil, err
}

// Skip to the next cluster if there are no tasks found on
// this cluster.
if len(tasks) == 0 {
continue
}

ec2Instances, err := p.lookupEc2Instances(ctx, client, &c, tasks)
if err != nil {
return nil, err
}

taskDefinitions, err := p.lookupTaskDefinitions(ctx, client, tasks)
if err != nil {
return nil, err
}

for key, task := range tasks {
containerInstance := ec2Instances[aws.StringValue(task.ContainerInstanceArn)]
taskDef := taskDefinitions[key]

for _, container := range task.Containers {
var containerDefinition *ecs.ContainerDefinition
for _, def := range taskDef.ContainerDefinitions {
if aws.StringValue(container.Name) == aws.StringValue(def.Name) {
containerDefinition = def
break
}
}

if containerDefinition == nil {
logger.Debugf("Unable to find container definition for %s", aws.StringValue(container.Name))
continue
}

var mach *machine
if len(task.Attachments) != 0 {
var ports []portMapping
for _, mapping := range containerDefinition.PortMappings {
if mapping != nil {
protocol := "TCP"
if aws.StringValue(mapping.Protocol) == "udp" {
protocol = "UDP"
}

ports = append(ports, portMapping{
hostPort: aws.Int64Value(mapping.HostPort),
containerPort: aws.Int64Value(mapping.ContainerPort),
protocol: protocol,
})
}
}
mach = &machine{
privateIP: aws.StringValue(container.NetworkInterfaces[0].PrivateIpv4Address),
ports: ports,
state: aws.StringValue(task.LastStatus),
healthStatus: aws.StringValue(task.HealthStatus),
}
} else {
if containerInstance == nil {
logger.Errorf("Unable to find container instance information for %s", aws.StringValue(container.Name))
continue
}

var ports []portMapping
for _, mapping := range container.NetworkBindings {
if mapping != nil {
ports = append(ports, portMapping{
hostPort: aws.Int64Value(mapping.HostPort),
containerPort: aws.Int64Value(mapping.ContainerPort),
})
}
}
mach = &machine{
privateIP: aws.StringValue(containerInstance.PrivateIpAddress),
ports: ports,
state: aws.StringValue(containerInstance.State.Name),
}
}

instance := ecsInstance{
Name: fmt.Sprintf("%s-%s", strings.Replace(aws.StringValue(task.Group), ":", "-", 1), *container.Name),
ID: key[len(key)-12:],
containerDefinition: containerDefinition,
machine: mach,
Labels: aws.StringValueMap(containerDefinition.DockerLabels),
}

extraConf, err := p.getConfiguration(instance)
if err != nil {
log.FromContext(ctx).Errorf("Skip container %s: %w", getServiceName(instance), err)
continue
}
instance.ExtraConf = extraConf

instances = append(instances, instance)
}
}
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: a3327c4430cf4a2cb35216776c2c9843281dec00