telegraf/plugins/inputs/ecs/client.go

125 lines
2.7 KiB
Go

package ecs
import (
"log"
"net/http"
"net/url"
"os"
"time"
"github.com/docker/docker/api/types"
)
var (
ecsMetadataPath, _ = url.Parse("/v2/metadata")
ecsMetaStatsPath, _ = url.Parse("/v2/stats")
)
// Client is the ECS client contract
type Client interface {
Task() (*Task, error)
ContainerStats() (map[string]types.StatsJSON, error)
}
type httpClient interface {
Do(req *http.Request) (*http.Response, error)
}
// NewEnvClient configures a new Client from the env
func NewEnvClient() (*EcsClient, error) {
timeout := 5 * time.Second
if t := os.Getenv("ECS_TIMEOUT"); t != "" {
if d, err := time.ParseDuration(t); err == nil {
timeout = d
}
}
return NewClient(
timeout,
)
}
// NewClient constructs an ECS client with the passed configuration params
func NewClient(timeout time.Duration) (*EcsClient, error) {
c := &http.Client{
Timeout: timeout,
}
return &EcsClient{
client: c,
}, nil
}
// EcsClient contains ECS connection config
type EcsClient struct {
client httpClient
BaseURL *url.URL
taskURL string
statsURL string
}
// Task calls the ECS metadata endpoint and returns a populated Task
func (c *EcsClient) Task() (*Task, error) {
if c.taskURL == "" {
c.taskURL = c.BaseURL.ResolveReference(ecsMetadataPath).String()
}
req, _ := http.NewRequest("GET", c.taskURL, nil)
resp, err := c.client.Do(req)
if err != nil {
log.Println("failed to GET metadata endpoint", err)
return nil, err
}
task, err := unmarshalTask(resp.Body)
if err != nil {
log.Println("failed to decode response from metadata endpoint", err)
return nil, err
}
return task, nil
}
// ContainerStats calls the ECS stats endpoint and returns a populated container stats map
func (c *EcsClient) ContainerStats() (map[string]types.StatsJSON, error) {
if c.statsURL == "" {
c.statsURL = c.BaseURL.ResolveReference(ecsMetaStatsPath).String()
}
req, _ := http.NewRequest("GET", c.statsURL, nil)
resp, err := c.client.Do(req)
if err != nil {
log.Println("failed to GET stats endpoint", err)
return map[string]types.StatsJSON{}, err
}
statsMap, err := unmarshalStats(resp.Body)
if err != nil {
log.Println("failed to decode response from stats endpoint")
return map[string]types.StatsJSON{}, err
}
return statsMap, nil
}
// PollSync executes Task and ContainerStats in parallel. If both succeed, both structs are returned.
// If either errors, a single error is returned.
func PollSync(c Client) (*Task, map[string]types.StatsJSON, error) {
var task *Task
var stats map[string]types.StatsJSON
var err error
if stats, err = c.ContainerStats(); err != nil {
return nil, nil, err
}
if task, err = c.Task(); err != nil {
return nil, nil, err
}
return task, stats, nil
}