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aws.go
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aws.go
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// Copyright 2018 Authors of Cilium
//
// 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 aws
import (
"fmt"
"net"
"os"
"github.com/aws/aws-sdk-go-v2/aws"
"github.com/aws/aws-sdk-go-v2/aws/external"
"github.com/aws/aws-sdk-go-v2/service/ec2"
"github.com/cilium/cilium/pkg/policy/api"
)
const (
awsLogLevel = aws.LogOff // For debugging pourposes can be set to aws.LogDebugWithSigning
awsDefaultRegionKey = "AWS_DEFAULT_REGION"
awsDefaultRegion = "eu-west-1"
)
var (
policySecurityGroupIDKey = aws.String("instance.group-id")
policySecurityGroupName = aws.String("instance.group-name")
policyEC2Labelskey = "tag"
)
func init() {
api.RegisterToGroupsProvider(api.AWSProvider, GetIPsFromGroup)
}
// GetIPsFromGroup will return the list of the ips for the given group filter
func GetIPsFromGroup(group *api.ToGroups) ([]net.IP, error) {
result := []net.IP{}
if group.AWS == nil {
return result, fmt.Errorf("no aws data available")
}
return getInstancesIpsFromFilter(group.AWS)
}
// initializeAWSAccount retrieve the env variables from the runtime and it
// iniliazes the account in the specified region.
func initializeAWSAccount(region string) (*aws.Config, error) {
cfg, err := external.LoadDefaultAWSConfig()
if err != nil {
return nil, fmt.Errorf("Cannot initialize aws connector: %s", err)
}
cfg.Region = region
cfg.LogLevel = awsLogLevel
return &cfg, nil
}
// getInstancesFromFilter returns the instances IPs in aws EC2 filter by the
// given filter
func getInstancesIpsFromFilter(filter *api.AWSGroup) ([]net.IP, error) {
region := filter.Region
if filter.Region == "" {
region = getDefaultRegion()
}
input := &ec2.DescribeInstancesInput{}
for labelKey, labelValue := range filter.Labels {
newFilter := ec2.Filter{
Name: aws.String(fmt.Sprintf("%s:%s", policyEC2Labelskey, labelKey)),
Values: []string{labelValue},
}
input.Filters = append(input.Filters, newFilter)
}
if len(filter.SecurityGroupsIds) > 0 {
newFilter := ec2.Filter{
Name: policySecurityGroupIDKey,
Values: filter.SecurityGroupsIds,
}
input.Filters = append(input.Filters, newFilter)
}
if len(filter.SecurityGroupsNames) > 0 {
newFilter := ec2.Filter{
Name: policySecurityGroupName,
Values: filter.SecurityGroupsNames,
}
input.Filters = append(input.Filters, newFilter)
}
cfg, err := initializeAWSAccount(region)
if err != nil {
return []net.IP{}, err
}
svc := ec2.New(*cfg)
req := svc.DescribeInstancesRequest(input)
result, err := req.Send()
if err != nil {
return []net.IP{}, fmt.Errorf("Cannot retrieve aws information: %s", err)
}
return awsDumpIpsFromRequest(result), nil
}
// getDefaultRegion returns the given region of the default one.
// @TODO retrieve the region from aws metadata.
func getDefaultRegion() string {
val := os.Getenv(awsDefaultRegionKey)
if val != "" {
return val
}
return awsDefaultRegion
}
func awsDumpIpsFromRequest(req *ec2.DescribeInstancesOutput) []net.IP {
result := []net.IP{}
for _, reservation := range req.Reservations {
for _, instance := range reservation.Instances {
for _, iface := range instance.NetworkInterfaces {
for _, ifaceIP := range iface.PrivateIpAddresses {
result = append(result, net.ParseIP(string(*ifaceIP.PrivateIpAddress)))
if ifaceIP.Association != nil {
result = append(result, net.ParseIP(string(*ifaceIP.Association.PublicIp)))
}
}
}
}
}
return result
}