prometheus/discovery/ec2/ec2.go
Benji Visser 46fb4078a6 handle nil pointer in ec2 discovery (#4469)
This handles a nil pointer that was being accessed in EC2 discovery.

Fixes: #4441

Signed-off-by: noqcks <benny@noqcks.io>
2018-08-07 08:35:22 +01:00

296 lines
8.5 KiB
Go

// Copyright 2015 The Prometheus Authors
// 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 ec2
import (
"context"
"fmt"
"net"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/credentials"
"github.com/aws/aws-sdk-go/aws/credentials/stscreds"
"github.com/aws/aws-sdk-go/aws/ec2metadata"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/aws/aws-sdk-go/service/ec2"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/prometheus/discovery/targetgroup"
"github.com/prometheus/prometheus/util/strutil"
)
const (
ec2Label = model.MetaLabelPrefix + "ec2_"
ec2LabelAZ = ec2Label + "availability_zone"
ec2LabelInstanceID = ec2Label + "instance_id"
ec2LabelInstanceState = ec2Label + "instance_state"
ec2LabelInstanceType = ec2Label + "instance_type"
ec2LabelPublicDNS = ec2Label + "public_dns_name"
ec2LabelPublicIP = ec2Label + "public_ip"
ec2LabelPrivateIP = ec2Label + "private_ip"
ec2LabelPrimarySubnetID = ec2Label + "primary_subnet_id"
ec2LabelSubnetID = ec2Label + "subnet_id"
ec2LabelTag = ec2Label + "tag_"
ec2LabelVPCID = ec2Label + "vpc_id"
subnetSeparator = ","
)
var (
ec2SDRefreshFailuresCount = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_sd_ec2_refresh_failures_total",
Help: "The number of EC2-SD scrape failures.",
})
ec2SDRefreshDuration = prometheus.NewSummary(
prometheus.SummaryOpts{
Name: "prometheus_sd_ec2_refresh_duration_seconds",
Help: "The duration of a EC2-SD refresh in seconds.",
})
// DefaultSDConfig is the default EC2 SD configuration.
DefaultSDConfig = SDConfig{
Port: 80,
RefreshInterval: model.Duration(60 * time.Second),
}
)
// Filter is the configuration for filtering EC2 instances.
type Filter struct {
Name string `yaml:"name"`
Values []string `yaml:"values"`
}
// SDConfig is the configuration for EC2 based service discovery.
type SDConfig struct {
Endpoint string `yaml:"endpoint"`
Region string `yaml:"region"`
AccessKey string `yaml:"access_key,omitempty"`
SecretKey config_util.Secret `yaml:"secret_key,omitempty"`
Profile string `yaml:"profile,omitempty"`
RoleARN string `yaml:"role_arn,omitempty"`
RefreshInterval model.Duration `yaml:"refresh_interval,omitempty"`
Port int `yaml:"port"`
Filters []*Filter `yaml:"filters"`
}
// UnmarshalYAML implements the yaml.Unmarshaler interface.
func (c *SDConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
*c = DefaultSDConfig
type plain SDConfig
err := unmarshal((*plain)(c))
if err != nil {
return err
}
if c.Region == "" {
sess, err := session.NewSession()
if err != nil {
return err
}
metadata := ec2metadata.New(sess)
region, err := metadata.Region()
if err != nil {
return fmt.Errorf("EC2 SD configuration requires a region")
}
c.Region = region
}
for _, f := range c.Filters {
if len(f.Values) == 0 {
return fmt.Errorf("EC2 SD configuration filter values cannot be empty")
}
}
return nil
}
func init() {
prometheus.MustRegister(ec2SDRefreshFailuresCount)
prometheus.MustRegister(ec2SDRefreshDuration)
}
// Discovery periodically performs EC2-SD requests. It implements
// the Discoverer interface.
type Discovery struct {
aws *aws.Config
interval time.Duration
profile string
roleARN string
port int
filters []*Filter
logger log.Logger
}
// NewDiscovery returns a new EC2Discovery which periodically refreshes its targets.
func NewDiscovery(conf *SDConfig, logger log.Logger) *Discovery {
creds := credentials.NewStaticCredentials(conf.AccessKey, string(conf.SecretKey), "")
if conf.AccessKey == "" && conf.SecretKey == "" {
creds = nil
}
if logger == nil {
logger = log.NewNopLogger()
}
return &Discovery{
aws: &aws.Config{
Endpoint: &conf.Endpoint,
Region: &conf.Region,
Credentials: creds,
},
profile: conf.Profile,
roleARN: conf.RoleARN,
filters: conf.Filters,
interval: time.Duration(conf.RefreshInterval),
port: conf.Port,
logger: logger,
}
}
// Run implements the Discoverer interface.
func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
ticker := time.NewTicker(d.interval)
defer ticker.Stop()
// Get an initial set right away.
tg, err := d.refresh()
if err != nil {
level.Error(d.logger).Log("msg", "Refresh failed", "err", err)
} else {
select {
case ch <- []*targetgroup.Group{tg}:
case <-ctx.Done():
return
}
}
for {
select {
case <-ticker.C:
tg, err := d.refresh()
if err != nil {
level.Error(d.logger).Log("msg", "Refresh failed", "err", err)
continue
}
select {
case ch <- []*targetgroup.Group{tg}:
case <-ctx.Done():
return
}
case <-ctx.Done():
return
}
}
}
func (d *Discovery) refresh() (tg *targetgroup.Group, err error) {
t0 := time.Now()
defer func() {
ec2SDRefreshDuration.Observe(time.Since(t0).Seconds())
if err != nil {
ec2SDRefreshFailuresCount.Inc()
}
}()
sess, err := session.NewSessionWithOptions(session.Options{
Config: *d.aws,
Profile: d.profile,
})
if err != nil {
return nil, fmt.Errorf("could not create aws session: %s", err)
}
var ec2s *ec2.EC2
if d.roleARN != "" {
creds := stscreds.NewCredentials(sess, d.roleARN)
ec2s = ec2.New(sess, &aws.Config{Credentials: creds})
} else {
ec2s = ec2.New(sess)
}
tg = &targetgroup.Group{
Source: *d.aws.Region,
}
var filters []*ec2.Filter
for _, f := range d.filters {
filters = append(filters, &ec2.Filter{
Name: aws.String(f.Name),
Values: aws.StringSlice(f.Values),
})
}
input := &ec2.DescribeInstancesInput{Filters: filters}
if err = ec2s.DescribeInstancesPages(input, func(p *ec2.DescribeInstancesOutput, lastPage bool) bool {
for _, r := range p.Reservations {
for _, inst := range r.Instances {
if inst.PrivateIpAddress == nil {
continue
}
labels := model.LabelSet{
ec2LabelInstanceID: model.LabelValue(*inst.InstanceId),
}
labels[ec2LabelPrivateIP] = model.LabelValue(*inst.PrivateIpAddress)
addr := net.JoinHostPort(*inst.PrivateIpAddress, fmt.Sprintf("%d", d.port))
labels[model.AddressLabel] = model.LabelValue(addr)
if inst.PublicIpAddress != nil {
labels[ec2LabelPublicIP] = model.LabelValue(*inst.PublicIpAddress)
labels[ec2LabelPublicDNS] = model.LabelValue(*inst.PublicDnsName)
}
labels[ec2LabelAZ] = model.LabelValue(*inst.Placement.AvailabilityZone)
labels[ec2LabelInstanceState] = model.LabelValue(*inst.State.Name)
labels[ec2LabelInstanceType] = model.LabelValue(*inst.InstanceType)
if inst.VpcId != nil {
labels[ec2LabelVPCID] = model.LabelValue(*inst.VpcId)
labels[ec2LabelPrimarySubnetID] = model.LabelValue(*inst.SubnetId)
// Deduplicate VPC Subnet IDs maintaining the order of the network interfaces returned by EC2.
var subnets []string
subnetsMap := make(map[string]struct{})
for _, eni := range inst.NetworkInterfaces {
if eni.SubnetId == nil {
continue
}
if _, ok := subnetsMap[*eni.SubnetId]; !ok {
subnetsMap[*eni.SubnetId] = struct{}{}
subnets = append(subnets, *eni.SubnetId)
}
}
labels[ec2LabelSubnetID] = model.LabelValue(
subnetSeparator +
strings.Join(subnets, subnetSeparator) +
subnetSeparator)
}
for _, t := range inst.Tags {
if t == nil || t.Key == nil || t.Value == nil {
continue
}
name := strutil.SanitizeLabelName(*t.Key)
labels[ec2LabelTag+model.LabelName(name)] = model.LabelValue(*t.Value)
}
tg.Targets = append(tg.Targets, labels)
}
}
return true
}); err != nil {
return nil, fmt.Errorf("could not describe instances: %s", err)
}
return tg, nil
}