initial commit

.gitignore

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+
+# Created by https://www.gitignore.io/api/go
+
+### Go ###
+# Binaries for programs and plugins
+*.exe
+*.dll
+*.so
+*.dylib
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
+.glide/
+vendor/
+
+# End of https://www.gitignore.io/api/go

README.md

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+# prometheus-swarm-discovery

glide.yaml

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+package: .
+import: []

swarm.go

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+package main
+
+import (
+ "context"
+ "encoding/json"
+ "fmt"
+ "io/ioutil"
+ "net"
+ "strings"
+
+ "github.com/docker/docker/api/types"
+ "github.com/docker/docker/api/types/filters"
+ "github.com/docker/docker/api/types/network"
+ "github.com/docker/docker/api/types/swarm"
+ "github.com/docker/docker/client"
+ "github.com/spf13/cobra"
+)
+
+var prometheusContainerID = "b171793f9e26"
+
+// allocateIP returns the 3rd last IP in the network range.
+func allocateIP(netCIDR *net.IPNet) string {
+
+ allocIP := net.IP(make([]byte, 4))
+ for i := range netCIDR.IP {
+ allocIP[i] = netCIDR.IP[i] | ^netCIDR.Mask[i]
+ }
+
+ allocIP[3] = allocIP[3] - 2
+ return allocIP.String()
+}
+
+func connectNetworks(networks map[string]swarm.Network) {
+ cli, err := client.NewEnvClient()
+ if err != nil {
+ panic(err)
+ }
+
+ prometheusContainer, err := cli.ContainerInspect(context.Background(), prometheusContainerID)
+ if err != nil {
+ panic(err)
+ }
+
+ promNetworks := make(map[string]*network.EndpointSettings)
+
+ for _, cntnet := range prometheusContainer.NetworkSettings.Networks {
+ promNetworks[cntnet.NetworkID] = cntnet
+ }
+
+ for id, netwrk := range networks {
+ if _, ok := promNetworks[id]; ok || len(netwrk.IPAMOptions.Configs) == 0 {
+ continue
+ }
+
+ _, netCIDR, err := net.ParseCIDR(netwrk.IPAMOptions.Configs[0].Subnet)
+ if err != nil {
+ panic(err)
+ }
+ prometheusIP := allocateIP(netCIDR)
+ fmt.Println("Connecting network ", netwrk.Spec.Name, "(", netCIDR.IP, ") to ", prometheusContainerID, "(", prometheusIP, ")")
+ netconfig := &network.EndpointSettings{
+ IPAMConfig: &network.EndpointIPAMConfig{
+ IPv4Address: prometheusIP,
+ },
+ }
+
+ err = cli.NetworkConnect(context.Background(), netwrk.ID, prometheusContainerID, netconfig)
+ if err != nil {
+ panic(err)
+ }
+
+ }
+
+}
+
+func writeSDConfig(scrapeTargets []scrapeTarget) {
+ jsonScrapeConfig, err := json.MarshalIndent(scrapeTargets, "", " ")
+ if err != nil {
+ panic(err)
+ }
+
+ fmt.Println("Writing config file.")
+
+ err = ioutil.WriteFile("swarm-endpoints.json", jsonScrapeConfig, 0644)
+ if err != nil {
+ panic(err)
+ }
+}
+
+type scrapeTarget struct {
+ Targets []string
+ Labels map[string]string
+}
+
+func discoverSwarm(cmd *cobra.Command, args []string) {
+ cli, err := client.NewEnvClient()
+ if err != nil {
+ panic(err)
+ }
+
+ networkFilters := filters.NewArgs()
+ networkFilters.Add("driver", "overlay")
+
+ networks, err := cli.NetworkList(context.Background(), types.NetworkListOptions{Filters: networkFilters})
+ if err != nil {
+ panic(err)
+ }
+
+ for _, network := range networks {
+ fmt.Printf("Network %s %s %s\n", network.ID, network.Name, network.Scope)
+ }
+
+ tasks, err := cli.TaskList(context.Background(), types.TaskListOptions{})
+ if err != nil {
+ panic(err)
+ }
+
+ var scrapeTargets []scrapeTarget
+ taskNetworks := make(map[string]swarm.Network)
+
+ for _, task := range tasks {
+ fmt.Printf("Task %s %s\n", task.ID, task.Name)
+ taskRaw, _, err := cli.TaskInspectWithRaw(context.Background(), task.ID)
+ if err != nil {
+ panic(err)
+ }
+ if len(taskRaw.NetworksAttachments) > 0 {
+ containerIP := strings.Split(taskRaw.NetworksAttachments[0].Addresses[0], "/")[0]
+ taskNetworks[taskRaw.NetworksAttachments[0].Network.ID] = taskRaw.NetworksAttachments[0].Network
+ scrapeTargets = append(scrapeTargets, scrapeTarget{Targets: []string{containerIP}, Labels: map[string]string{"labelname": "value"}})
+ }
+ }
+
+ connectNetworks(taskNetworks)
+ writeSDConfig(scrapeTargets)
+}
+
+func main() {
+
+ var cmdDiscover = &cobra.Command{
+ Use: "discover",
+ Short: "Starts Swarm service discovery",
+ Run: discoverSwarm,
+ }
+
+ var rootCmd = &cobra.Command{Use: "promswarm"}
+ rootCmd.AddCommand(cmdDiscover)
+ rootCmd.Execute()
+
+}