Initial commit

.gitignore

@@ -0,0 +1 @@
+build/

Makefile

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+
+GO			= go
+GOCCFLAGS 	= -v
+GOLDFLAGS   =
+PREFIX		= /usr/local
+
+PROGRAM_NAME=eos-api-healthcheck
+SOURCES=server.go
+DEPENDANCIES= github.com/firstrow/tcp_server \
+	github.com/liamylian/jsontime/v2 \
+	github.com/imroc/req
+
+all: build
+build: build/$(PROGRAM_NAME)
+
+build/$(PROGRAM_NAME) : $(SOURCES)
+	$(GO) build -o $@ $(GOCCFLAGS) $(GOLDFLAGS) $<
+
+deps:
+	$(GO) get $(DEPENDANCIES)
+
+package_deb: build
+	export PACKAGE_NAME="$(PROGRAM_NAME)" \
+	export PACKAGE_VERSION="0.1.0" \
+	export PACKAGE_PREFIX=$(PREFIX:/%=%) \
+	export PACKAGE_PROGRAM="build/$(PROGRAM_NAME)" \
+	&& ./scripts/build_deb.sh
+
+clean:
+	$(GO) clean
+	$(RM) -rf build/

eosapi/functions.go

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+
+package eosapi;
+
+import (
+    "fmt"
+	"time"
+	"io/ioutil"
+	"github.com/imroc/req"
+	"github.com/liamylian/jsontime/v2"
+)
+
+var json = v2.ConfigWithCustomTimeFormat;
+
+func init() {
+
+	// EOS Api does not specify timezone in timestamps (they are always UTC tho).
+	v2.SetDefaultTimeFormat("2006-01-02T15:04:05", time.UTC);
+}
+
+//  GetInfo - Fetches get_info from API
+// ---------------------------------------------------------
+func GetInfo(host string, port int) (Info, error) {
+
+	var info Info;
+
+	// Format url.
+	url := fmt.Sprintf("http://%s:%d/v1/chain/get_info", host, port);
+
+	// Go's net.http (that `req` uses) sends the port in the host header.
+	// nodeos api does not like that, so we need to provide our
+	// own Host header with just the host.
+	headers := req.Header{
+		"Host": host,
+	}
+
+	// Send HTTP Get request.
+	r, err := req.Get(url, headers)
+	resp := r.Response()
+	body, _ := ioutil.ReadAll(resp.Body);
+
+	// Parse json
+	err = json.Unmarshal(body, &info);
+	return info, err;
+}

eosapi/types.go

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+
+package eosapi;
+
+import "time";
+
+// get_info format (not all fields).
+type Info struct {
+	ServerVersion 	string 		`json:"server_version"`
+	HeadBlockNum 	int64 		`json:"head_block_num"`
+	HeadBlockTime 	time.Time 	`json:"head_block_time"`
+}

haproxy/types.go

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+
+package haproxy;
+
+// All supported health check values for HAproxy.
+// See https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#5.2-agent-check
+type HealthCheckStatus string
+const (
+	HealthCheckUp 		= "up"
+	HealthCheckDown 	= "down"
+	HealthCheckMaint 	= "maint"
+	HealthCheckReady	= "ready"
+	HealthCheckDrain	= "drain"
+	HealthCheckFailed 	= "failed"
+	HealthCheckStopped 	= "Stopped"
+)

scripts/.gitignore

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+pack/
+*.deb

scripts/build_deb.sh

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+#!/usr/bin/env bash
+
+BASE_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
+PACKAGE_DESCRIPTION="HAproxy healthcheck program for EOS API."
+PACKAGE_TMPDIR="pack"
+
+# Default to 1 if no release is set.
+if [[ -z $RELEASE ]]; then
+  RELEASE="1"
+fi
+
+PACKAGE_FULLNAME="${PACKAGE_NAME}_${PACKAGE_VERSION}-${RELEASE}_amd64"
+
+rm -fr ${BASE_DIR}/${PACKAGE_TMPDIR}
+
+# Create debian files.
+mkdir -p ${BASE_DIR}/${PACKAGE_TMPDIR}/DEBIAN
+echo "Package: ${PACKAGE_NAME}
+Version: ${PACKAGE_VERSION}-${RELEASE}
+Section: introspection
+Priority: optional
+Architecture: amd64
+Homepage: https://github.com/eosswedenorg/eos-api-healthcheck
+Maintainer: Henrik Hautakoski <henrik@eossweden.org>
+Description: ${PACKAGE_DESCRIPTION}" &> ${BASE_DIR}/${PACKAGE_TMPDIR}/DEBIAN/control
+
+cat ${BASE_DIR}/${PACKAGE_TMPDIR}/DEBIAN/control
+
+# Create service file
+mkdir -p ${BASE_DIR}/${PACKAGE_TMPDIR}/etc/systemd/system
+cat ${BASE_DIR}/template.service \
+	| sed "s~{{ DESCRIPTION }}~${PACKAGE_DESCRIPTION}~" \
+	| sed "s~{{ PROGRAM }}~/${PACKAGE_PREFIX}/bin/${PACKAGE_NAME}~" \
+	> ${BASE_DIR}/${PACKAGE_TMPDIR}/etc/systemd/system/${PACKAGE_NAME}.service
+
+# Copy program
+mkdir -p ${BASE_DIR}/${PACKAGE_TMPDIR}/${PACKAGE_PREFIX}/bin
+cp ${BASE_DIR}/../${PACKAGE_PROGRAM} ${BASE_DIR}/${PACKAGE_TMPDIR}/${PACKAGE_PREFIX}/bin/${PACKAGE_NAME}
+
+fakeroot dpkg-deb --build ${BASE_DIR}/${PACKAGE_TMPDIR} ${BASE_DIR}/${PACKAGE_FULLNAME}.deb

scripts/template.service

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+[Unit]
+Description={{ DESCRIPTION }}
+After=network.target
+
+[Service]
+Type=simple
+# Another Type: forking
+#User=nanodano
+#WorkingDirectory=/home/nanodano
+ExecStart={{ PROGRAM }}
+Restart=on-failure
+# Other restart options: always, on-abort, etc
+
+# The install section is needed to use
+# `systemctl enable` to start on boot
+# For a user service that you want to enable
+# and start automatically, use `default.target`
+# For system level services, use `multi-user.target`
+[Install]
+WantedBy=multi-user.target

server.go

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+package main
+
+import (
+	"os"
+    "fmt"
+	"time"
+	"strings"
+	"strconv"
+	"./haproxy"
+	"./eosapi"
+    "github.com/firstrow/tcp_server"
+)
+
+//  check_api - Validates head block time.
+// ---------------------------------------------------------
+func check_api(host string, port int) (haproxy.HealthCheckStatus, string) {
+
+	info, err := eosapi.GetInfo(host, port)
+	if err != nil {
+		msg := fmt.Sprintf("%s", err);
+		return haproxy.HealthCheckFailed, msg
+	}
+
+	// Validate head block.
+	now  := time.Now().In(time.UTC)
+	diff := now.Sub(info.HeadBlockTime).Seconds()
+
+	if diff > 10.0 {
+		return haproxy.HealthCheckDown,
+			fmt.Sprintf("Taking offline because head block is lagging %.0f seconds", diff)
+	} else if diff < -10.0 {
+		return haproxy.HealthCheckDown,
+			fmt.Sprintf("Taking offline because head block is %.0f seconds into the future", diff)
+	}
+	return haproxy.HealthCheckUp, "OK"
+}
+
+//  argv_listen_addr
+//    Parse listen address from command line.
+// ---------------------------------------------------------
+func argv_listen_addr() string {
+
+	var addr string
+
+	argv := os.Args[1:]
+	if len(argv) > 0 {
+		addr = argv[0]
+	} else {
+		addr = "127.0.0.1"
+	}
+
+	addr += ":"
+	if len(argv) > 1 {
+		addr += argv[1]
+	} else {
+		addr += "1337"
+	}
+
+	return addr
+}
+
+//  main
+// ---------------------------------------------------------
+func main() {
+
+    server := tcp_server.New(argv_listen_addr())
+
+	// TCP Client connect.
+    server.OnNewClient(func(c *tcp_server.Client) {
+        fmt.Println("# Client connected")
+    });
+
+	// TCP Client sends message.
+	server.OnNewMessage(func(c *tcp_server.Client, message string) {
+		var host string
+		var port int = 80
+
+		// Parse host + port.
+		split := strings.Split(strings.TrimSpace(message), ":")
+
+		host = split[0]
+		if len(split) > 1 {
+			p, err := strconv.ParseInt(split[1], 10, 32)
+			if err == nil {
+				port = int(p)
+			}
+		}
+
+		// Check api.
+		status, msg := check_api(host, port)
+
+		fmt.Printf("API HealthCheck: %s, %s\n", status, msg)
+
+		// Report status to HAproxy
+		c.Send(fmt.Sprintln(status))
+        c.Close()
+	});
+
+	// TCP Client disconnect.
+	server.OnClientConnectionClosed(func(c *tcp_server.Client, err error) {
+		fmt.Println("# Client disconnected")
+	});
+
+    server.Listen()
+}