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HTTP API for receiving signal requests and passing it to the wrapped …
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,90 +1,94 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "encoding/json" | ||
| "errors" | ||
| "fmt" | ||
| "net/http" | ||
| "io" | ||
| "os" | ||
| "os/exec" | ||
| "path" | ||
| "os/signal" | ||
|
|
||
| "jarnfast/signalman/pkg" | ||
| "jarnfast/signalman/pkg/api" | ||
| "jarnfast/signalman/pkg/cmdwrapper" | ||
| "jarnfast/signalman/pkg/utl" | ||
|
|
||
| "go.uber.org/zap" | ||
| ) | ||
|
|
||
| var version string = "1.0" | ||
| var build string = "n/a" | ||
| func createLogger() *zap.SugaredLogger { | ||
| var config zap.Config | ||
|
|
||
| type handlers struct { | ||
| } | ||
| configFilename := os.Getenv("SIGNALMAN_LOG_CONFIGFILE") | ||
|
|
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| type adminPortal struct { | ||
| } | ||
| if configFilename != "" { | ||
| configFile, err := os.Open(configFilename) | ||
| if err != nil { | ||
| panic(fmt.Sprintf("Unable to open config file: %v", err)) | ||
|
|
||
| func newAdminPortal() *adminPortal { | ||
| return &adminPortal{} | ||
| } | ||
| } | ||
| rawJSON, err := io.ReadAll(configFile) | ||
| if err != nil { | ||
| panic(fmt.Sprintf("Unable to read config file: %v", err)) | ||
| } | ||
|
|
||
| func (h *handlers) status(response http.ResponseWriter, request *http.Request) { | ||
| response.WriteHeader(http.StatusOK) | ||
| response.Write([]byte(versionString())) | ||
| response.Write([]byte(fmt.Sprintf("Args: %d, %s", len(os.Args[1:]), os.Args[1:]))) | ||
| } | ||
| if err := json.Unmarshal(rawJSON, &config); err != nil { | ||
| panic(fmt.Sprintf("Unable to parse config file as JSON: %v", err)) | ||
| } | ||
|
|
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| func (h *handlers) signal(response http.ResponseWriter, request *http.Request) { | ||
| if request.Method != "GET" { | ||
| response.WriteHeader(http.StatusMethodNotAllowed) | ||
| return | ||
| } else { | ||
| config = zap.NewProductionConfig() | ||
| var err error | ||
| config.Level, err = zap.ParseAtomicLevel(utl.GetenvDefault("SIGNALMAN_LOG_LEVEL", "info")) | ||
| if err != nil { | ||
| panic(err) | ||
| } | ||
| } | ||
| fmt.Println("Get request", request.URL) | ||
| } | ||
| func (h *handlers) kill(response http.ResponseWriter, request *http.Request) { | ||
| os.Exit(1337) | ||
| } | ||
| func versionString() string { | ||
| //return fmt.Sprintf("%s version %s (build %s)", path.Base(os.Args[0]), version, build) | ||
| return fmt.Sprintf("%s version %s (build %s)", path.Base(os.Args[0]), pkg.Version, build) | ||
|
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| logger, _ := config.Build() | ||
|
|
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| defer logger.Sync() | ||
|
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| sugar := logger.Sugar() | ||
| return sugar | ||
| } | ||
|
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| func main() { | ||
| fmt.Println("Starting", versionString()) | ||
| logger := createLogger() | ||
|
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||
| addr := os.Getenv("SIGNALMAN_LISTEN_ADDRESS") | ||
| if addr == "" { | ||
| addr = "localhost:30000" | ||
| } | ||
| logger.Infof("Starting %s", pkg.VersionString()) | ||
|
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||
| h := &handlers{} | ||
| http.HandleFunc("/status", h.status) | ||
| http.HandleFunc("/kill", h.kill) | ||
| http.HandleFunc("/signal/", h.signal) | ||
| sigs := make(chan os.Signal, 10) | ||
|
|
||
| go func() { | ||
| err := http.ListenAndServe(addr, nil) | ||
| if err != nil { | ||
| panic(err) | ||
| } | ||
| }() | ||
| // Relay incoming signals to process | ||
| signal.Notify(sigs) | ||
|
|
||
| fmt.Println("Listening for commands on", addr) | ||
| a := api.NewApi(logger) | ||
| // Relay signals received on HTTP | ||
| a.Notify(sigs) | ||
| a.ListenAndServe() | ||
|
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| args := os.Args[1:] | ||
| binary, err := exec.LookPath(args[0]) | ||
| if err != nil { | ||
| fmt.Println("Command not found", binary) | ||
| panic(err) | ||
| } | ||
| c := cmdwrapper.NewCmdWrapper(logger) | ||
| // Subscribe on the received signals | ||
| c.Subscribe(sigs) | ||
| c.Start() | ||
|
|
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| exitCode, err := c.Wait() | ||
|
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| cmd := exec.Command(binary, args[1:]...) | ||
| cmd.Stdout = os.Stdout | ||
| cmd.Stderr = os.Stderr | ||
| cmd.Stdin = os.Stdin | ||
| close(sigs) | ||
|
|
||
| err = cmd.Start() | ||
| if err != nil { | ||
| fmt.Println("Unable to run command", err) | ||
| panic(err) | ||
| exitCode := -1 | ||
| // try to get the original exit code | ||
| var exitError *exec.ExitError | ||
| if errors.As(err, &exitError) { | ||
| exitCode = exitError.ExitCode() | ||
| } | ||
| logger.Warnf("Wrapped command finished with error: %v", err) | ||
| os.Exit(exitCode) | ||
| } else { | ||
| logger.Info("Wrapped command finished without errors") | ||
| os.Exit(exitCode) | ||
| } | ||
|
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| cmd.Wait() | ||
|
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||
| fmt.Println("Command terminated") | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,3 +1,10 @@ | ||
| module jarnfast/signalman | ||
|
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||
| go 1.19 | ||
|
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| require ( | ||
| github.com/spf13/cast v1.5.0 // indirect | ||
| go.uber.org/atomic v1.7.0 // indirect | ||
| go.uber.org/multierr v1.6.0 // indirect | ||
| go.uber.org/zap v1.24.0 // indirect | ||
| ) |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,13 @@ | ||
| github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= | ||
| github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= | ||
| github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= | ||
| github.com/spf13/cast v1.5.0 h1:rj3WzYc11XZaIZMPKmwP96zkFEnnAmV8s6XbB2aY32w= | ||
| github.com/spf13/cast v1.5.0/go.mod h1:SpXXQ5YoyJw6s3/6cMTQuxvgRl3PCJiyaX9p6b155UU= | ||
| github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= | ||
| github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI= | ||
| go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw= | ||
| go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc= | ||
| go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4= | ||
| go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU= | ||
| go.uber.org/zap v1.24.0 h1:FiJd5l1UOLj0wCgbSE0rwwXHzEdAZS6hiiSnxJN/D60= | ||
| go.uber.org/zap v1.24.0/go.mod h1:2kMP+WWQ8aoFoedH3T2sq6iJ2yDWpHbP0f6MQbS9Gkg= |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,133 @@ | ||
| package api | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "jarnfast/signalman/pkg" | ||
| "jarnfast/signalman/pkg/utl" | ||
| "os" | ||
| "strconv" | ||
| "strings" | ||
| "syscall" | ||
| "time" | ||
|
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| "net/http" | ||
|
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| "github.com/spf13/cast" | ||
| "go.uber.org/zap" | ||
| ) | ||
|
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| type Api struct { | ||
| addr string | ||
| logger *zap.SugaredLogger | ||
| sigs chan<- os.Signal | ||
| } | ||
|
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| func NewApi(logger *zap.SugaredLogger) *Api { | ||
| addr := utl.GetenvDefault("SIGNALMAN_LISTEN_ADDRESS", "localhost:30000") | ||
|
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| return &Api{ | ||
| addr: addr, | ||
| logger: logger, | ||
| } | ||
| } | ||
|
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| // Notify causes api to relay signal received on HTTP to c. | ||
| func (a *Api) Notify(c chan<- os.Signal) { | ||
| a.sigs = c | ||
| } | ||
|
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| func (a *Api) debugLogRequest(r *http.Request) { | ||
| a.logger.Debugf("HTTP Request: %s %s", r.Method, r.URL) | ||
| } | ||
|
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| func (a *Api) handleStatus(w http.ResponseWriter, r *http.Request) { | ||
| a.debugLogRequest(r) | ||
|
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| if r.Method != "GET" { | ||
| w.WriteHeader(http.StatusMethodNotAllowed) | ||
| return | ||
| } | ||
| w.WriteHeader(http.StatusOK) | ||
| w.Write([]byte(pkg.VersionString())) | ||
| } | ||
|
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| func (a *Api) handleSignal(w http.ResponseWriter, r *http.Request) { | ||
| a.debugLogRequest(r) | ||
|
|
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| if r.Method != "POST" { | ||
| w.WriteHeader(http.StatusMethodNotAllowed) | ||
| return | ||
| } | ||
|
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| parts := strings.Split(r.URL.String(), "/") | ||
|
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| if len(parts) != 3 { | ||
| w.WriteHeader(http.StatusBadRequest) | ||
| return | ||
| } | ||
|
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| i, err := strconv.Atoi(parts[2]) | ||
| if err != nil { | ||
| m := fmt.Sprintf("Unable to parse signal as int: %s", parts[2]) | ||
| a.logger.Debug(m) | ||
| w.WriteHeader(http.StatusBadRequest) | ||
| w.Write([]byte(m)) | ||
| return | ||
| } | ||
|
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| w.WriteHeader(http.StatusAccepted) | ||
|
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| s := syscall.Signal(i) | ||
|
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| a.sigs <- s | ||
|
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| w.Write([]byte(fmt.Sprintf("Got signal (%d) %s\r\n", len(parts), parts[2]))) | ||
| w.Write([]byte("This signal is: ")) | ||
| w.Write([]byte(strconv.Itoa(i))) | ||
| } | ||
|
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| func (a *Api) handleTerm(w http.ResponseWriter, r *http.Request) { | ||
| a.debugLogRequest(r) | ||
|
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| w.WriteHeader(http.StatusAccepted) | ||
|
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| a.sigs <- syscall.SIGTERM | ||
|
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| timeval := cast.ToDuration(utl.GetenvDefault("SIGNALMAN_TERM_TIMEOUT", "10")) | ||
| <-time.After(timeval * time.Second) | ||
|
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| a.logger.Warnf("Wrapped command did not react to TERM within %d seconds. Sending KILL.", timeval) | ||
|
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| a.sigs <- syscall.SIGKILL | ||
| } | ||
|
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| func (a *Api) handleKill(w http.ResponseWriter, r *http.Request) { | ||
| a.debugLogRequest(r) | ||
|
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| w.WriteHeader(http.StatusAccepted) | ||
| a.sigs <- syscall.SIGKILL | ||
| } | ||
|
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| // ListenAndServe listens on the configured TCP network address and relays received | ||
| // signals to the configured channel | ||
| func (a *Api) ListenAndServe() { | ||
|
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| if a.sigs == nil { | ||
| a.logger.Panic("No signal channel found") | ||
| } | ||
|
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| mux := http.NewServeMux() | ||
| mux.HandleFunc("/status", a.handleStatus) | ||
| mux.HandleFunc("/signal/", a.handleSignal) | ||
| mux.HandleFunc("/term", a.handleTerm) | ||
| mux.HandleFunc("/kill", a.handleKill) | ||
|
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| go func() { | ||
| err := http.ListenAndServe(a.addr, mux) | ||
| if err != nil { | ||
| a.logger.Panic(err) | ||
| } | ||
| }() | ||
|
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| a.logger.Infof("Listening for commands on %s", a.addr) | ||
| } |
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