Serge Bazanski | 3d116b2 | 2021-03-27 15:43:18 +0000 | [diff] [blame] | 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "flag" |
| 7 | "fmt" |
| 8 | "net/http" |
| 9 | "sync" |
| 10 | "time" |
| 11 | |
| 12 | "code.hackerspace.pl/hscloud/go/mirko" |
| 13 | "github.com/golang/glog" |
| 14 | "github.com/grpc-ecosystem/grpc-gateway/runtime" |
| 15 | |
| 16 | pb "code.hackerspace.pl/hscloud/personal/q3k/shipstuck/proto" |
| 17 | ) |
| 18 | |
| 19 | type vessel struct { |
Serge Bazanski | 5c1ab3c | 2021-03-27 15:57:16 +0000 | [diff] [blame] | 20 | Speed float64 `json:"ss"` |
Serge Bazanski | 3d116b2 | 2021-03-27 15:43:18 +0000 | [diff] [blame] | 21 | } |
| 22 | |
| 23 | // get retrieves the current status of the ship - returns true if stack, false |
| 24 | // otherwise. |
| 25 | func get(ctx context.Context) (bool, error) { |
| 26 | // Sorry vesselfinder, if you made it easy to set up an account I would |
| 27 | // gladly pay for the API instead of doing this. Limiting requests to once |
| 28 | // every 15 minutes though, that seems fair enough. |
| 29 | req, err := http.NewRequestWithContext(ctx, "GET", "https://www.vesselfinder.com/api/pub/click/353136000", nil) |
| 30 | if err != nil { |
| 31 | return false, fmt.Errorf("NewRequestWithContext: %w", err) |
| 32 | } |
| 33 | req.Header.Set("User-Agent", "Mozilla/5.0 (X11; Linux x86_64; rv:86.0) Gecko/20100101 Firefox/86.0") |
| 34 | |
| 35 | res, err := http.DefaultClient.Do(req) |
| 36 | if err != nil { |
| 37 | return false, fmt.Errorf("Do: %w", err) |
| 38 | } |
| 39 | |
| 40 | defer res.Body.Close() |
| 41 | |
| 42 | v := &vessel{} |
| 43 | err = json.NewDecoder(res.Body).Decode(v) |
| 44 | if err != nil { |
| 45 | return false, fmt.Errorf("Decode: %w", err) |
| 46 | } |
| 47 | |
Serge Bazanski | 5c1ab3c | 2021-03-27 15:57:16 +0000 | [diff] [blame] | 48 | if v.Speed == 0.0 { |
Serge Bazanski | 3d116b2 | 2021-03-27 15:43:18 +0000 | [diff] [blame] | 49 | return true, nil |
| 50 | } else { |
| 51 | glog.Infof("Freed! %+v", v) |
| 52 | return false, nil |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | type shipState string |
| 57 | |
| 58 | const ( |
| 59 | shipStateUnknown shipState = "UNKNOWN" |
| 60 | shipStateStuck shipState = "STUCK" |
| 61 | shipStateFreed shipState = "FREED" |
| 62 | ) |
| 63 | |
| 64 | type service struct { |
| 65 | lastStateMu sync.RWMutex |
| 66 | lastState shipState |
| 67 | lastStateTime time.Time |
| 68 | } |
| 69 | |
| 70 | func (s *service) worker(ctx context.Context) { |
| 71 | update := func() { |
| 72 | state := shipStateUnknown |
| 73 | // shitty back off, good enough. |
| 74 | retries := 10 |
| 75 | for { |
| 76 | stuck, err := get(ctx) |
| 77 | if err != nil { |
| 78 | glog.Warningf("get: %v", err) |
| 79 | if retries > 0 { |
| 80 | time.Sleep(60 * time.Second) |
| 81 | retries -= 1 |
| 82 | } else { |
| 83 | glog.Errorf("giving up on get") |
| 84 | break |
| 85 | } |
| 86 | } else { |
| 87 | if stuck { |
| 88 | state = shipStateStuck |
| 89 | } else { |
| 90 | state = shipStateFreed |
| 91 | } |
| 92 | break |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | glog.Infof("New state: %v", state) |
| 97 | s.lastStateMu.Lock() |
| 98 | s.lastState = state |
| 99 | s.lastStateTime = time.Now() |
| 100 | s.lastStateMu.Unlock() |
| 101 | } |
| 102 | |
| 103 | update() |
| 104 | ticker := time.NewTicker(15 * 60 * time.Second) |
| 105 | for { |
| 106 | select { |
| 107 | case <-ctx.Done(): |
| 108 | return |
| 109 | case <-ticker.C: |
| 110 | update() |
| 111 | } |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | func timeMust(t time.Time, err error) time.Time { |
| 116 | if err != nil { |
| 117 | panic(err) |
| 118 | } |
| 119 | return t |
| 120 | } |
| 121 | |
| 122 | var ( |
| 123 | timeStuck = timeMust(time.Parse( |
Serge Bazanski | 5da0494 | 2021-03-27 16:03:45 +0000 | [diff] [blame] | 124 | "At 15:04 Eastern European Time (-0700) on 2 January 2006", |
| 125 | "At 07:40 Eastern European Time (+0200) on 23 March 2021", |
Serge Bazanski | 3d116b2 | 2021-03-27 15:43:18 +0000 | [diff] [blame] | 126 | )) |
| 127 | ) |
| 128 | |
| 129 | func (s *service) Status(ctx context.Context, req *pb.StatusRequest) (*pb.StatusResponse, error) { |
| 130 | s.lastStateMu.RLock() |
| 131 | state := s.lastState |
| 132 | lastChecked := s.lastStateTime |
| 133 | s.lastStateMu.RUnlock() |
| 134 | |
| 135 | res := &pb.StatusResponse{ |
| 136 | LastChecked: lastChecked.UnixNano(), |
| 137 | } |
| 138 | switch state { |
| 139 | case shipStateUnknown: |
| 140 | res.Current = pb.StatusResponse_STUCKNESS_UNKNOWN |
| 141 | case shipStateStuck: |
| 142 | res.Current = pb.StatusResponse_STUCKNESS_STUCK |
| 143 | res.Elapsed = time.Since(timeStuck).Nanoseconds() |
| 144 | case shipStateFreed: |
| 145 | res.Current = pb.StatusResponse_STUCKNESS_FREE |
| 146 | } |
| 147 | |
| 148 | return res, nil |
| 149 | } |
| 150 | |
| 151 | var ( |
| 152 | flagPublicAddress string |
| 153 | ) |
| 154 | |
| 155 | func main() { |
| 156 | flag.StringVar(&flagPublicAddress, "public_address", "127.0.0.1:8080", "Public HTTP/JSON listen address") |
| 157 | flag.Parse() |
| 158 | m := mirko.New() |
| 159 | if err := m.Listen(); err != nil { |
| 160 | glog.Exitf("Listen(): %v", err) |
| 161 | } |
| 162 | |
| 163 | s := &service{} |
| 164 | pb.RegisterShipStuckServer(m.GRPC(), s) |
| 165 | |
| 166 | publicMux := runtime.NewServeMux() |
| 167 | publicSrv := http.Server{ |
| 168 | Addr: flagPublicAddress, |
| 169 | Handler: publicMux, |
| 170 | } |
| 171 | go func() { |
| 172 | glog.Infof("REST listening on %s", flagPublicAddress) |
| 173 | if err := publicSrv.ListenAndServe(); err != nil { |
| 174 | glog.Exitf("public ListenAndServe: %v", err) |
| 175 | } |
| 176 | }() |
| 177 | if err := pb.RegisterShipStuckHandlerServer(m.Context(), publicMux, s); err != nil { |
| 178 | glog.Exitf("RegisterShipStuckHandlerSerever: %v", err) |
| 179 | } |
| 180 | |
| 181 | go s.worker(m.Context()) |
| 182 | |
| 183 | if err := m.Serve(); err != nil { |
| 184 | glog.Exitf("Serve(): %v", err) |
| 185 | } |
| 186 | |
| 187 | <-m.Done() |
| 188 | } |