prometheus/discovery/marathon/marathon.go
Simon Pasquier 22a1def98d
Merge pull request #5099 from prometheus/release-2.6
Merge release-2.6 to master
2019-01-16 09:26:00 +01:00

533 lines
17 KiB
Go

// Copyright 2016 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 marathon
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"math/rand"
"net"
"net/http"
"strconv"
"strings"
"time"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
"github.com/prometheus/client_golang/prometheus"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/discovery/targetgroup"
"github.com/prometheus/prometheus/util/strutil"
)
const (
// metaLabelPrefix is the meta prefix used for all meta labels in this discovery.
metaLabelPrefix = model.MetaLabelPrefix + "marathon_"
// appLabelPrefix is the prefix for the application labels.
appLabelPrefix = metaLabelPrefix + "app_label_"
// appLabel is used for the name of the app in Marathon.
appLabel model.LabelName = metaLabelPrefix + "app"
// imageLabel is the label that is used for the docker image running the service.
imageLabel model.LabelName = metaLabelPrefix + "image"
// portIndexLabel is the integer port index when multiple ports are defined;
// e.g. PORT1 would have a value of '1'
portIndexLabel model.LabelName = metaLabelPrefix + "port_index"
// taskLabel contains the mesos task name of the app instance.
taskLabel model.LabelName = metaLabelPrefix + "task"
// portMappingLabelPrefix is the prefix for the application portMappings labels.
portMappingLabelPrefix = metaLabelPrefix + "port_mapping_label_"
// portDefinitionLabelPrefix is the prefix for the application portDefinitions labels.
portDefinitionLabelPrefix = metaLabelPrefix + "port_definition_label_"
// Constants for instrumentation.
namespace = "prometheus"
)
var (
refreshFailuresCount = prometheus.NewCounter(
prometheus.CounterOpts{
Namespace: namespace,
Name: "sd_marathon_refresh_failures_total",
Help: "The number of Marathon-SD refresh failures.",
})
refreshDuration = prometheus.NewSummary(
prometheus.SummaryOpts{
Namespace: namespace,
Name: "sd_marathon_refresh_duration_seconds",
Help: "The duration of a Marathon-SD refresh in seconds.",
})
// DefaultSDConfig is the default Marathon SD configuration.
DefaultSDConfig = SDConfig{
RefreshInterval: model.Duration(30 * time.Second),
}
)
// SDConfig is the configuration for services running on Marathon.
type SDConfig struct {
Servers []string `yaml:"servers,omitempty"`
RefreshInterval model.Duration `yaml:"refresh_interval,omitempty"`
AuthToken config_util.Secret `yaml:"auth_token,omitempty"`
AuthTokenFile string `yaml:"auth_token_file,omitempty"`
HTTPClientConfig config_util.HTTPClientConfig `yaml:",inline"`
}
// 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 len(c.Servers) == 0 {
return fmt.Errorf("marathon_sd: must contain at least one Marathon server")
}
if len(c.AuthToken) > 0 && len(c.AuthTokenFile) > 0 {
return fmt.Errorf("marathon_sd: at most one of auth_token & auth_token_file must be configured")
}
if c.HTTPClientConfig.BasicAuth != nil && (len(c.AuthToken) > 0 || len(c.AuthTokenFile) > 0) {
return fmt.Errorf("marathon_sd: at most one of basic_auth, auth_token & auth_token_file must be configured")
}
if (len(c.HTTPClientConfig.BearerToken) > 0 || len(c.HTTPClientConfig.BearerTokenFile) > 0) && (len(c.AuthToken) > 0 || len(c.AuthTokenFile) > 0) {
return fmt.Errorf("marathon_sd: at most one of bearer_token, bearer_token_file, auth_token & auth_token_file must be configured")
}
return c.HTTPClientConfig.Validate()
}
func init() {
prometheus.MustRegister(refreshFailuresCount)
prometheus.MustRegister(refreshDuration)
}
const appListPath string = "/v2/apps/?embed=apps.tasks"
// Discovery provides service discovery based on a Marathon instance.
type Discovery struct {
client *http.Client
servers []string
refreshInterval time.Duration
lastRefresh map[string]*targetgroup.Group
appsClient AppListClient
logger log.Logger
}
// NewDiscovery returns a new Marathon Discovery.
func NewDiscovery(conf SDConfig, logger log.Logger) (*Discovery, error) {
if logger == nil {
logger = log.NewNopLogger()
}
rt, err := config_util.NewRoundTripperFromConfig(conf.HTTPClientConfig, "marathon_sd")
if err != nil {
return nil, err
}
if len(conf.AuthToken) > 0 {
rt, err = newAuthTokenRoundTripper(conf.AuthToken, rt)
} else if len(conf.AuthTokenFile) > 0 {
rt, err = newAuthTokenFileRoundTripper(conf.AuthTokenFile, rt)
}
if err != nil {
return nil, err
}
return &Discovery{
client: &http.Client{Transport: rt},
servers: conf.Servers,
refreshInterval: time.Duration(conf.RefreshInterval),
appsClient: fetchApps,
logger: logger,
}, nil
}
type authTokenRoundTripper struct {
authToken config_util.Secret
rt http.RoundTripper
}
// newAuthTokenRoundTripper adds the provided auth token to a request.
func newAuthTokenRoundTripper(token config_util.Secret, rt http.RoundTripper) (http.RoundTripper, error) {
return &authTokenRoundTripper{token, rt}, nil
}
func (rt *authTokenRoundTripper) RoundTrip(request *http.Request) (*http.Response, error) {
// According to https://docs.mesosphere.com/1.11/security/oss/managing-authentication/
// DC/OS wants with "token=" a different Authorization header than implemented in httputil/client.go
// so we set this explicitly here.
request.Header.Set("Authorization", "token="+string(rt.authToken))
return rt.rt.RoundTrip(request)
}
type authTokenFileRoundTripper struct {
authTokenFile string
rt http.RoundTripper
}
// newAuthTokenFileRoundTripper adds the auth token read from the file to a request.
func newAuthTokenFileRoundTripper(tokenFile string, rt http.RoundTripper) (http.RoundTripper, error) {
// fail-fast if we can't read the file.
_, err := ioutil.ReadFile(tokenFile)
if err != nil {
return nil, fmt.Errorf("unable to read auth token file %s: %s", tokenFile, err)
}
return &authTokenFileRoundTripper{tokenFile, rt}, nil
}
func (rt *authTokenFileRoundTripper) RoundTrip(request *http.Request) (*http.Response, error) {
b, err := ioutil.ReadFile(rt.authTokenFile)
if err != nil {
return nil, fmt.Errorf("unable to read auth token file %s: %s", rt.authTokenFile, err)
}
authToken := strings.TrimSpace(string(b))
// According to https://docs.mesosphere.com/1.11/security/oss/managing-authentication/
// DC/OS wants with "token=" a different Authorization header than implemented in httputil/client.go
// so we set this explicitly here.
request.Header.Set("Authorization", "token="+authToken)
return rt.rt.RoundTrip(request)
}
// Run implements the Discoverer interface.
func (d *Discovery) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
for {
select {
case <-ctx.Done():
return
case <-time.After(d.refreshInterval):
err := d.updateServices(ctx, ch)
if err != nil {
level.Error(d.logger).Log("msg", "Error while updating services", "err", err)
}
}
}
}
func (d *Discovery) updateServices(ctx context.Context, ch chan<- []*targetgroup.Group) (err error) {
t0 := time.Now()
defer func() {
refreshDuration.Observe(time.Since(t0).Seconds())
if err != nil {
refreshFailuresCount.Inc()
}
}()
targetMap, err := d.fetchTargetGroups()
if err != nil {
return err
}
all := make([]*targetgroup.Group, 0, len(targetMap))
for _, tg := range targetMap {
all = append(all, tg)
}
select {
case <-ctx.Done():
return ctx.Err()
case ch <- all:
}
// Remove services which did disappear.
for source := range d.lastRefresh {
_, ok := targetMap[source]
if !ok {
select {
case <-ctx.Done():
return ctx.Err()
case ch <- []*targetgroup.Group{{Source: source}}:
level.Debug(d.logger).Log("msg", "Removing group", "source", source)
}
}
}
d.lastRefresh = targetMap
return nil
}
func (d *Discovery) fetchTargetGroups() (map[string]*targetgroup.Group, error) {
url := RandomAppsURL(d.servers)
apps, err := d.appsClient(d.client, url)
if err != nil {
return nil, err
}
groups := AppsToTargetGroups(apps)
return groups, nil
}
// Task describes one instance of a service running on Marathon.
type Task struct {
ID string `json:"id"`
Host string `json:"host"`
Ports []uint32 `json:"ports"`
IPAddresses []IPAddress `json:"ipAddresses"`
}
// IPAddress describes the address and protocol the container's network interface is bound to.
type IPAddress struct {
Address string `json:"ipAddress"`
Proto string `json:"protocol"`
}
// PortMapping describes in which port the process are binding inside the docker container.
type PortMapping struct {
Labels map[string]string `json:"labels"`
ContainerPort uint32 `json:"containerPort"`
HostPort uint32 `json:"hostPort"`
ServicePort uint32 `json:"servicePort"`
}
// DockerContainer describes a container which uses the docker runtime.
type DockerContainer struct {
Image string `json:"image"`
PortMappings []PortMapping `json:"portMappings"`
}
// Container describes the runtime an app in running in.
type Container struct {
Docker DockerContainer `json:"docker"`
PortMappings []PortMapping `json:"portMappings"`
}
// PortDefinition describes which load balancer port you should access to access the service.
type PortDefinition struct {
Labels map[string]string `json:"labels"`
Port uint32 `json:"port"`
}
// Network describes the name and type of network the container is attached to.
type Network struct {
Name string `json:"name"`
Mode string `json:"mode"`
}
// App describes a service running on Marathon.
type App struct {
ID string `json:"id"`
Tasks []Task `json:"tasks"`
RunningTasks int `json:"tasksRunning"`
Labels map[string]string `json:"labels"`
Container Container `json:"container"`
PortDefinitions []PortDefinition `json:"portDefinitions"`
Networks []Network `json:"networks"`
RequirePorts bool `json:"requirePorts"`
}
// isContainerNet checks if the app's first network is set to mode 'container'.
func (app App) isContainerNet() bool {
return len(app.Networks) > 0 && app.Networks[0].Mode == "container"
}
// AppList is a list of Marathon apps.
type AppList struct {
Apps []App `json:"apps"`
}
// AppListClient defines a function that can be used to get an application list from marathon.
type AppListClient func(client *http.Client, url string) (*AppList, error)
// fetchApps requests a list of applications from a marathon server.
func fetchApps(client *http.Client, url string) (*AppList, error) {
request, err := http.NewRequest("GET", url, nil)
if err != nil {
return nil, err
}
resp, err := client.Do(request)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if (resp.StatusCode < 200) || (resp.StatusCode >= 300) {
return nil, fmt.Errorf("non 2xx status '%v' response during marathon service discovery", resp.StatusCode)
}
var apps AppList
err = json.NewDecoder(resp.Body).Decode(&apps)
if err != nil {
return nil, fmt.Errorf("%q: %v", url, err)
}
return &apps, nil
}
// RandomAppsURL randomly selects a server from an array and creates
// an URL pointing to the app list.
func RandomAppsURL(servers []string) string {
// TODO: If possible update server list from Marathon at some point.
server := servers[rand.Intn(len(servers))]
return fmt.Sprintf("%s%s", server, appListPath)
}
// AppsToTargetGroups takes an array of Marathon apps and converts them into target groups.
func AppsToTargetGroups(apps *AppList) map[string]*targetgroup.Group {
tgroups := map[string]*targetgroup.Group{}
for _, a := range apps.Apps {
group := createTargetGroup(&a)
tgroups[group.Source] = group
}
return tgroups
}
func createTargetGroup(app *App) *targetgroup.Group {
var (
targets = targetsForApp(app)
appName = model.LabelValue(app.ID)
image = model.LabelValue(app.Container.Docker.Image)
)
tg := &targetgroup.Group{
Targets: targets,
Labels: model.LabelSet{
appLabel: appName,
imageLabel: image,
},
Source: app.ID,
}
for ln, lv := range app.Labels {
ln = appLabelPrefix + strutil.SanitizeLabelName(ln)
tg.Labels[model.LabelName(ln)] = model.LabelValue(lv)
}
return tg
}
func targetsForApp(app *App) []model.LabelSet {
targets := make([]model.LabelSet, 0, len(app.Tasks))
var ports []uint32
var labels []map[string]string
var prefix string
if len(app.Container.PortMappings) != 0 {
// In Marathon 1.5.x the "container.docker.portMappings" object was moved
// to "container.portMappings".
ports, labels = extractPortMapping(app.Container.PortMappings, app.isContainerNet())
prefix = portMappingLabelPrefix
} else if len(app.Container.Docker.PortMappings) != 0 {
// Prior to Marathon 1.5 the port mappings could be found at the path
// "container.docker.portMappings".
ports, labels = extractPortMapping(app.Container.Docker.PortMappings, app.isContainerNet())
prefix = portMappingLabelPrefix
} else if len(app.PortDefinitions) != 0 {
// PortDefinitions deprecates the "ports" array and can be used to specify
// a list of ports with metadata in case a mapping is not required.
ports = make([]uint32, len(app.PortDefinitions))
labels = make([]map[string]string, len(app.PortDefinitions))
for i := 0; i < len(app.PortDefinitions); i++ {
labels[i] = app.PortDefinitions[i].Labels
// When requirePorts is false, this port becomes the 'servicePort', not the listen port.
// In this case, the port needs to be taken from the task instead of the app.
if app.RequirePorts {
ports[i] = app.PortDefinitions[i].Port
}
}
prefix = portDefinitionLabelPrefix
}
// Gather info about the app's 'tasks'. Each instance (container) is considered a task
// and can be reachable at one or more host:port endpoints.
for _, t := range app.Tasks {
// There are no labels to gather if only Ports is defined. (eg. with host networking)
// Ports can only be gathered from the Task (not from the app) and are guaranteed
// to be the same across all tasks. If we haven't gathered any ports by now,
// use the task's ports as the port list.
if len(ports) == 0 && len(t.Ports) != 0 {
ports = t.Ports
}
// Iterate over the ports we gathered using one of the methods above.
for i, port := range ports {
// A zero port here means that either the portMapping has a zero port defined,
// or there is a portDefinition with requirePorts set to false. This means the port
// is auto-generated by Mesos and needs to be looked up in the task.
if port == 0 && len(t.Ports) == len(ports) {
port = t.Ports[i]
}
// Each port represents a possible Prometheus target.
targetAddress := targetEndpoint(&t, port, app.isContainerNet())
target := model.LabelSet{
model.AddressLabel: model.LabelValue(targetAddress),
taskLabel: model.LabelValue(t.ID),
portIndexLabel: model.LabelValue(strconv.Itoa(i)),
}
// Gather all port labels and set them on the current target, skip if the port has no Marathon labels.
// This will happen in the host networking case with only `ports` defined, where
// it is inefficient to allocate a list of possibly hundreds of empty label maps per host port.
if len(labels) > 0 {
for ln, lv := range labels[i] {
ln = prefix + strutil.SanitizeLabelName(ln)
target[model.LabelName(ln)] = model.LabelValue(lv)
}
}
targets = append(targets, target)
}
}
return targets
}
// Generate a target endpoint string in host:port format.
func targetEndpoint(task *Task, port uint32, containerNet bool) string {
var host string
// Use the task's ipAddress field when it's in a container network
if containerNet && len(task.IPAddresses) > 0 {
host = task.IPAddresses[0].Address
} else {
host = task.Host
}
return net.JoinHostPort(host, fmt.Sprintf("%d", port))
}
// Get a list of ports and a list of labels from a PortMapping.
func extractPortMapping(portMappings []PortMapping, containerNet bool) ([]uint32, []map[string]string) {
ports := make([]uint32, len(portMappings))
labels := make([]map[string]string, len(portMappings))
for i := 0; i < len(portMappings); i++ {
labels[i] = portMappings[i].Labels
if containerNet {
// If the app is in a container network, connect directly to the container port.
ports[i] = portMappings[i].ContainerPort
} else {
// Otherwise, connect to the allocated host port for the container.
// Note that this host port is likely set to 0 in the app definition, which means it is
// automatically generated and needs to be extracted from the task's 'ports' array at a later stage.
ports[i] = portMappings[i].HostPort
}
}
return ports, labels
}