harness-drone/cmd/drone-agent/health.go
2018-03-21 14:02:17 +01:00

145 lines
3.2 KiB
Go

// Copyright 2018 Drone.IO Inc.
//
// 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 main
import (
"encoding/json"
"fmt"
"io"
"net/http"
"sync"
"time"
"github.com/drone/drone/version"
"github.com/urfave/cli"
)
// the file implements some basic healthcheck logic based on the
// following specification:
// https://github.com/mozilla-services/Dockerflow
func init() {
http.HandleFunc("/varz", handleStats)
http.HandleFunc("/healthz", handleHeartbeat)
http.HandleFunc("/version", handleVersion)
}
func handleHeartbeat(w http.ResponseWriter, r *http.Request) {
if counter.Healthy() {
w.WriteHeader(200)
} else {
w.WriteHeader(500)
}
}
func handleVersion(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(200)
w.Header().Add("Content-Type", "text/json")
json.NewEncoder(w).Encode(versionResp{
Source: "https://github.com/drone/drone",
Version: version.Version.String(),
})
}
func handleStats(w http.ResponseWriter, r *http.Request) {
if counter.Healthy() {
w.WriteHeader(200)
} else {
w.WriteHeader(500)
}
w.Header().Add("Content-Type", "text/json")
counter.writeTo(w)
}
type versionResp struct {
Version string `json:"version"`
Source string `json:"source"`
}
// default statistics counter
var counter = &state{
Metadata: map[string]info{},
}
type state struct {
sync.Mutex `json:"-"`
Polling int `json:"polling_count"`
Running int `json:"running_count"`
Metadata map[string]info `json:"running"`
}
type info struct {
ID string `json:"id"`
Repo string `json:"repository"`
Build string `json:"build_number"`
Started time.Time `json:"build_started"`
Timeout time.Duration `json:"build_timeout"`
}
func (s *state) Add(id string, timeout time.Duration, repo, build string) {
s.Lock()
s.Polling--
s.Running++
s.Metadata[id] = info{
ID: id,
Repo: repo,
Build: build,
Timeout: timeout,
Started: time.Now().UTC(),
}
s.Unlock()
}
func (s *state) Done(id string) {
s.Lock()
s.Polling++
s.Running--
delete(s.Metadata, id)
s.Unlock()
}
func (s *state) Healthy() bool {
s.Lock()
defer s.Unlock()
now := time.Now()
buf := time.Hour // 1 hour buffer
for _, item := range s.Metadata {
if now.After(item.Started.Add(item.Timeout).Add(buf)) {
return false
}
}
return true
}
func (s *state) writeTo(w io.Writer) (int, error) {
s.Lock()
out, _ := json.Marshal(s)
s.Unlock()
return w.Write(out)
}
// handles pinging the endpoint and returns an error if the
// agent is in an unhealthy state.
func pinger(c *cli.Context) error {
resp, err := http.Get("http://localhost:3000/healthz")
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
return fmt.Errorf("agent returned non-200 status code")
}
return nil
}