feat: add healtcheck tip check

ref #1

Signed-off-by: Marko Kungla <marko.kungla@gmail.com>

cmd-api.go

@@ -28,9 +28,6 @@ import (
 	"github.com/cardano-community/koios-go-client"
 )
 
-//nolint: gochecknoglobals
-var api *koios.Client
-
 func attachAPICommmand(app *cli.App) {
 	apicmd := &cli.Command{
 		Name:     "api",

cmd-healthcheck.go

@@ -0,0 +1,184 @@
+// Copyright 2022 The Cardano Community Authors
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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
+//   or LICENSE file in repository root.
+//
+// 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 (
+	"context"
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/urfave/cli/v2"
+
+	"github.com/cardano-community/koios-go-client"
+)
+
+type HealthcheckResponse struct {
+	Tip struct {
+		koios.Response
+		Data            *koios.Tip    `json:"data,omitempty"`
+		LastBlockAgeNs  time.Duration `json:"last_block_age_ns"`
+		LastBlockAgeStr string        `json:"last_block_age_str"`
+		TipTimoutNs     time.Duration `json:"tip_timeout_ns"`
+		TipTimoutStr    string        `json:"tip_timeout_str"`
+	} `json:"chk_tip"`
+
+	RPC struct {
+	} `json:"chk_rpcs"`
+	Cache struct {
+	} `json:"chk_cache_status"`
+	Limit struct {
+	} `json:"chk_limit"`
+	Endpoints []struct {
+		Endpoint string `json:"endpoint"`
+	} `json:"chk_endpt_get"`
+}
+
+func attachHealthcheckCommmand(app *cli.App) {
+	hcmd := &cli.Command{
+		Name:     "healthcheck",
+		Category: "GENERAL",
+		Usage:    "perform healthcheck against Koios instances",
+		Flags: []cli.Flag{
+			&cli.IntFlag{
+				Name:    "timeout",
+				Usage:   "Seconds when request will timeout.",
+				Aliases: []string{"t"},
+				Value:   2,
+			},
+			&cli.IntFlag{
+				Name:    "age",
+				Usage:   "Maximum allowed age of last block in seconds.",
+				Aliases: []string{"a"},
+				Value:   600,
+			},
+			&cli.BoolFlag{
+				Name:  "quiet",
+				Usage: "do not print nothing to sdtout",
+				Value: false,
+			},
+
+			&cli.UintFlag{
+				Name:    "port",
+				Aliases: []string{"p"},
+				Usage:   "Set port",
+				Value:   uint(koios.DefaultPort),
+			},
+			&cli.StringFlag{
+				Name:  "host",
+				Usage: "Set host",
+				Value: koios.MainnetHost,
+			},
+			&cli.StringFlag{
+				Name:  "api-version",
+				Usage: "Set API version",
+				Value: koios.DefaultAPIVersion,
+			},
+			&cli.StringFlag{
+				Name:  "scheme",
+				Usage: "Set URL scheme",
+				Value: koios.DefaultScheme,
+			},
+			&cli.BoolFlag{
+				Name:  "no-format",
+				Usage: "prints response json strings directly without calling json pretty.",
+				Value: false,
+			},
+		},
+		Before: func(c *cli.Context) error {
+			var (
+				hostopt koios.Option
+				err     error
+			)
+			if c.Bool("testnet") {
+				hostopt = koios.Host(koios.TestnetHost)
+			} else {
+				hostopt = koios.Host(c.String("host"))
+			}
+
+			api, err = koios.New(
+				hostopt,
+				koios.APIVersion(c.String("api-version")),
+				koios.Port(uint16(c.Uint("port"))),
+				koios.Scheme(c.String("scheme")),
+				koios.CollectRequestsStats(true),
+			)
+
+			return err
+		},
+		Action: func(ctx *cli.Context) error {
+			tiptimeout := time.Second * time.Duration(ctx.Int("timeout"))
+			tipage := time.Second * time.Duration(ctx.Int("age"))
+			tipctx, tipcancel := context.WithTimeout(callctx, tiptimeout)
+			defer tipcancel()
+
+			res := HealthcheckResponse{}
+			var failed bool
+
+			// CHECK TIP
+			// replace ./scripts/grest-helper-scripts/grest-poll.sh#L80
+			// function chk_tip()
+			res.Tip.TipTimoutNs = tiptimeout
+			res.Tip.TipTimoutStr = tiptimeout.String()
+			tipres, err := api.GetTip(tipctx)
+
+			//nolint: nestif
+			if err != nil {
+				if err.Error() == "context deadline exceeded" {
+					tipres.StatusCode = http.StatusRequestTimeout
+					tipres.Status = http.StatusText(http.StatusRequestTimeout)
+					tipres.Error.Code = fmt.Sprint(http.StatusRequestTimeout)
+					tipres.Error.Message = fmt.Sprintf("instance did not respond within %s", tiptimeout)
+					tipres.Error.Details = "to increase the timeout value adjust the --timeout flag value (n) seconds"
+				}
+				failed = true
+			} else {
+				reqtime, err := time.Parse(time.RFC1123, tipres.Date)
+				if err != nil {
+					return err
+				}
+				blocktime, err := time.Parse("2006-01-02T15:04:05", tipres.Data.BlockTime)
+				if err != nil {
+					return err
+				}
+				res.Tip.LastBlockAgeNs = reqtime.Sub(blocktime)
+				res.Tip.LastBlockAgeStr = res.Tip.LastBlockAgeNs.String()
+				res.Tip.Response = tipres.Response
+				res.Tip.Data = tipres.Data
+
+				if res.Tip.LastBlockAgeNs > tipage {
+					failed = true
+				}
+			}
+
+			// Output if quiet flag is not present
+			if !ctx.Bool("quiet") {
+				apiOutput(ctx, res, nil)
+			}
+
+			// exit with code 1 if any checks failed
+			if failed {
+				os.Exit(1)
+			}
+
+			return nil
+		},
+	}
+
+	app.Commands = append(app.Commands, hcmd)
+}

main.go

@@ -28,17 +28,23 @@ import (
 	"runtime/debug"
 
 	"github.com/urfave/cli/v2"
+
+	"github.com/cardano-community/koios-go-client"
 )
 
 //nolint: gochecknoglobals
 var (
+	ErrCommand = errors.New("command error")
+
 	callctx context.Context
 	cancel  context.CancelFunc
 
 	// Populated by goreleaser during build.
-	version    = "dev"
-	date       = ""
-	ErrCommand = errors.New("command error")
+	version = "dev"
+	date    = ""
+
+	//nolint: gochecknoglobals
+	api *koios.Client
 )
 
 //nolint:gochecknoinits
@@ -71,6 +77,7 @@ func main() {
 	}
 
 	attachAPICommmand(app)
+	attachHealthcheckCommmand(app)
 	handleErr(app.Run(os.Args))
 }