Update error string when failing to send alert

Wrap both originating errors

.drone.yml

@@ -4,7 +4,7 @@ name: test
 
 steps:
   - name: test
-    image: golang:1.17
+    image: golang:1.20
     environment:
       VERSION: ${DRONE_TAG:-${DRONE_COMMIT}}
     commands:
@@ -30,7 +30,7 @@ trigger:
 
 steps:
   - name: build all binaries
-    image: golang:1.17
+    image: golang:1.20
     environment:
       VERSION: ${DRONE_TAG:-${DRONE_COMMIT}}
     commands:

Dockerfile

@@ -1,5 +1,5 @@
 ARG REPO=library
-FROM ${REPO}/alpine:3.17
+FROM ${REPO}/alpine:3.18
 
 RUN mkdir /app
 WORKDIR /app/

Dockerfile.multi-stage

@@ -1,5 +1,5 @@
 ARG REPO=library
-FROM golang:1.17 AS builder
+FROM golang:1.20 AS builder
 
 RUN mkdir /app
 WORKDIR /app
@@ -14,7 +14,7 @@ ARG VERSION=dev
 ENV CGO_ENABLED=0 GOOS=linux GOARCH=${ARCH}
 RUN go build -ldflags "-X main.version=${VERSION}" -a -installsuffix nocgo -o minitor .
 
-FROM ${REPO}/alpine:3.17
+FROM ${REPO}/alpine:3.18
 RUN mkdir /app
 WORKDIR /app/
 

README.md

@@ -94,10 +94,28 @@ Also, when alerts are executed, they will be passed through Go's format function
 |`{{.AlertCount}}`|Number of times this monitor has alerted|
 |`{{.FailureCount}}`|The total number of sequential failed checks for this monitor|
 |`{{.LastCheckOutput}}`|The last returned value from the check command to either stderr or stdout|
-|`{{.LastSuccess}}`|The ISO datetime of the last successful check|
+|`{{.LastSuccess}}`|The datetime of the last successful check as a go Time struct|
 |`{{.MonitorName}}`|The name of the monitor that failed and triggered the alert|
 |`{{.IsUp}}`|Indicates if the monitor that is alerting is up or not. Can be used in a conditional message template|
 
+To provide flexible formatting, the following non-standard functions are available in templates:
+
+|func|description|
+|---|---|
+|`ANSIC <Time>`|Formats provided time in ANSIC format|
+|`UnixDate <Time>`|Formats provided time in UnixDate format|
+|`RubyDate <Time>`|Formats provided time in RubyDate format|
+|`RFC822Z <Time>`|Formats provided time in RFC822Z format|
+|`RFC850 <Time>`|Formats provided time in RFC850 format|
+|`RFC1123 <Time>`|Formats provided time in RFC1123 format|
+|`RFC1123Z <Time>`|Formats provided time in RFC1123Z format|
+|`RFC3339 <Time>`|Formats provided time in RFC3339 format|
+|`RFC3339Nano <Time>`|Formats provided time in RFC3339Nano format|
+|`FormatTime <Time> <string template>`|Formats provided time according to provided template|
+|`InTZ <Time> <string timezone name>`|Converts provided time to parsed timezone from the provided name|
+
+For more information, check out the [Go documentation for the time module](https://pkg.go.dev/time@go1.20.7#pkg-constants).
+
 ### Metrics
 
 Minitor supports exporting metrics for [Prometheus](https://prometheus.io/). Prometheus is an open source tool for reading and querying metrics from different sources. Combined with another tool, [Grafana](https://grafana.com/), it allows building of charts and dashboards. You could also opt to just use Minitor to log check results, and instead do your alerting with Grafana.
@@ -158,7 +176,7 @@ minitor-go:
 check_interval: 1m30s
 ```
 
-The `-py-compat` flag has been removed. Any existing Python oriented configuration needs to be migrated to the new templates.
+For the time being, legacy configs for the Python version of Minitor should be compatible if you apply the `-py-compat` flag when running Minitor. Eventually, this flag will go away when later breaking changes are introduced.
 
 ## Future
 

alert.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"os/exec"
+	"strings"
 	"text/template"
 	"time"
 
@@ -44,21 +45,70 @@ func (alert Alert) IsValid() bool {
 
 // BuildTemplates compiles command templates for the Alert
 func (alert *Alert) BuildTemplates() error {
+	// TODO: Remove legacy template support later after 1.0
+	legacy := strings.NewReplacer(
+		"{alert_count}", "{{.AlertCount}}",
+		"{alert_message}", "{{.MonitorName}} check has failed {{.FailureCount}} times",
+		"{failure_count}", "{{.FailureCount}}",
+		"{last_output}", "{{.LastCheckOutput}}",
+		"{last_success}", "{{.LastSuccess}}",
+		"{monitor_name}", "{{.MonitorName}}",
+	)
+
 	slog.Debugf("Building template for alert %s", alert.Name)
 
+	// Time format func factory
+	tff := func(formatString string) func(time.Time) string {
+		return func(t time.Time) string {
+			return t.Format(formatString)
+		}
+	}
+
+	// Create some functions for formatting datetimes in popular formats
+	timeFormatFuncs := template.FuncMap{
+		"ANSIC":       tff(time.ANSIC),
+		"UnixDate":    tff(time.UnixDate),
+		"RubyDate":    tff(time.RubyDate),
+		"RFC822Z":     tff(time.RFC822Z),
+		"RFC850":      tff(time.RFC850),
+		"RFC1123":     tff(time.RFC1123),
+		"RFC1123Z":    tff(time.RFC1123Z),
+		"RFC3339":     tff(time.RFC3339),
+		"RFC3339Nano": tff(time.RFC3339Nano),
+		"FormatTime": func(t time.Time, timeFormat string) string {
+			return t.Format(timeFormat)
+		},
+		"InTZ": func(t time.Time, tzName string) (time.Time, error) {
+			tz, err := time.LoadLocation(tzName)
+			if err != nil {
+				return t, fmt.Errorf("failed to convert time to specified tz: %w", err)
+			}
+
+			return t.In(tz), nil
+		},
+	}
+
 	switch {
 	case alert.commandTemplate == nil && alert.Command.Command != nil:
 		alert.commandTemplate = []*template.Template{}
 		for i, cmdPart := range alert.Command.Command {
+			if PyCompat {
+				cmdPart = legacy.Replace(cmdPart)
+			}
+
 			alert.commandTemplate = append(alert.commandTemplate, template.Must(
-				template.New(alert.Name+fmt.Sprint(i)).Parse(cmdPart),
+				template.New(alert.Name+fmt.Sprint(i)).Funcs(timeFormatFuncs).Parse(cmdPart),
 			))
 		}
 	case alert.commandShellTemplate == nil && alert.Command.ShellCommand != "":
 		shellCmd := alert.Command.ShellCommand
 
+		if PyCompat {
+			shellCmd = legacy.Replace(shellCmd)
+		}
+
 		alert.commandShellTemplate = template.Must(
-			template.New(alert.Name).Parse(shellCmd),
+			template.New(alert.Name).Funcs(timeFormatFuncs).Parse(shellCmd),
 		)
 	default:
 		return fmt.Errorf("No template provided for alert %s: %w", alert.Name, errNoTemplate)
@@ -118,7 +168,7 @@ func (alert Alert) Send(notice AlertNotice) (outputStr string, err error) {
 
 	if err != nil {
 		err = fmt.Errorf(
-			"Alert '%s' failed to send. Returned %v: %w",
+			"Alert %s failed to send. Returned %w: %w",
 			alert.Name,
 			err,
 			ErrAlertFailed,

alert_test.go

@@ -70,6 +70,14 @@ func TestAlertSend(t *testing.T) {
 			"Command shell with bad template",
 			false,
 		},
+		{
+			Alert{Command: CommandOrShell{ShellCommand: "echo {alert_message}"}},
+			AlertNotice{MonitorName: "test", FailureCount: 1},
+			"test check has failed 1 times\n",
+			false,
+			"Command shell with legacy template",
+			true,
+		},
 		// Test default log alert down
 		{
 			*NewLogAlert(),
@@ -92,6 +100,8 @@ func TestAlertSend(t *testing.T) {
 
 	for _, c := range cases {
 		log.Printf("Testing case %s", c.name)
+		// Set PyCompat to value of compat flag
+		PyCompat = c.pyCompat
 
 		err := c.alert.BuildTemplates()
 		if err != nil {
@@ -111,6 +121,9 @@ func TestAlertSend(t *testing.T) {
 			log.Printf("Case failed: %s", c.name)
 		}
 
+		// Set PyCompat back to default value
+		PyCompat = false
+
 		log.Println("-----")
 	}
 }

config.go

@@ -13,11 +13,11 @@ var errInvalidConfig = errors.New("Invalid configuration")
 
 // Config type is contains all provided user configuration
 type Config struct {
-	CheckInterval     time.Duration `yaml:"check_interval"`
+	CheckInterval     SecondsOrDuration `yaml:"check_interval"`
-	DefaultAlertAfter int16         `yaml:"default_alert_after"`
+	DefaultAlertAfter int16             `yaml:"default_alert_after"`
-	DefaultAlertEvery *int16        `yaml:"default_alert_every"`
+	DefaultAlertEvery *int16            `yaml:"default_alert_every"`
-	DefaultAlertDown  []string      `yaml:"default_alert_down"`
+	DefaultAlertDown  []string          `yaml:"default_alert_down"`
-	DefaultAlertUp    []string      `yaml:"default_alert_up"`
+	DefaultAlertUp    []string          `yaml:"default_alert_up"`
 	Monitors          []*Monitor
 	Alerts            map[string]*Alert
 }
@@ -56,6 +56,34 @@ func (cos *CommandOrShell) UnmarshalYAML(unmarshal func(interface{}) error) erro
 	return nil
 }
 
+// SecondsOrDuration wraps a duration value for parsing a duration or seconds from YAML
+// NOTE: This should be removed in favor of only parsing durations once compatibility is broken
+type SecondsOrDuration struct {
+	value time.Duration
+}
+
+// Value returns a duration value
+func (sod SecondsOrDuration) Value() time.Duration {
+	return sod.value
+}
+
+// UnmarshalYAML allows unmarshalling a duration value or seconds if an int was provided
+func (sod *SecondsOrDuration) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	var seconds int64
+	err := unmarshal(&seconds)
+
+	if err == nil {
+		sod.value = time.Second * time.Duration(seconds)
+
+		return nil
+	}
+
+	// Error indicates that we don't have an int
+	err = unmarshal(&sod.value)
+
+	return err
+}
+
 // IsValid checks config validity and returns true if valid
 func (config Config) IsValid() (isValid bool) {
 	isValid = true
@@ -154,6 +182,18 @@ func LoadConfig(filePath string) (config Config, err error) {
 
 	slog.Debugf("Config values:\n%v\n", config)
 
+	// Add log alert if not present
+	if PyCompat {
+		// Initialize alerts list if not present
+		if config.Alerts == nil {
+			config.Alerts = map[string]*Alert{}
+		}
+
+		if _, ok := config.Alerts["log"]; !ok {
+			config.Alerts["log"] = NewLogAlert()
+		}
+	}
+
 	// Finish initializing configuration
 	if err = config.Init(); err != nil {
 		return

config_test.go

@@ -15,6 +15,7 @@ func TestLoadConfig(t *testing.T) {
 	}{
 		{"./test/valid-config.yml", false, "Valid config file", false},
 		{"./test/valid-config-default-values.yml", false, "Valid config file with default values", false},
+		{"./test/valid-default-log-alert.yml", false, "Valid config file with default log alert PyCompat", true},
 		{"./test/valid-default-log-alert.yml", true, "Invalid config file no log alert", false},
 		{"./test/does-not-exist", true, "Invalid config path", false},
 		{"./test/invalid-config-type.yml", true, "Invalid config type for key", false},
@@ -24,6 +25,8 @@ func TestLoadConfig(t *testing.T) {
 
 	for _, c := range cases {
 		log.Printf("Testing case %s", c.name)
+		// Set PyCompat based on compatibility mode
+		PyCompat = c.pyCompat
 		_, err := LoadConfig(c.configPath)
 		hasErr := (err != nil)
 
@@ -31,6 +34,9 @@ func TestLoadConfig(t *testing.T) {
 			t.Errorf("LoadConfig(%v), expected_error=%v actual=%v", c.name, c.expectErr, err)
 			log.Printf("Case failed: %s", c.name)
 		}
+
+		// Set PyCompat to default value
+		PyCompat = false
 	}
 }
 
@@ -47,15 +53,15 @@ func TestIntervalParsing(t *testing.T) {
 	oneMinute := time.Minute
 
 	// validate top level interval seconds represented as an int
-	if config.CheckInterval != oneSecond {
+	if config.CheckInterval.Value() != oneSecond {
 		t.Errorf("Incorrectly parsed int seconds. expected=%v actual=%v", oneSecond, config.CheckInterval)
 	}
 
-	if config.Monitors[0].CheckInterval != tenSeconds {
+	if config.Monitors[0].CheckInterval.Value() != tenSeconds {
 		t.Errorf("Incorrectly parsed seconds duration. expected=%v actual=%v", oneSecond, config.CheckInterval)
 	}
 
-	if config.Monitors[1].CheckInterval != oneMinute {
+	if config.Monitors[1].CheckInterval.Value() != oneMinute {
 		t.Errorf("Incorrectly parsed seconds duration. expected=%v actual=%v", oneSecond, config.CheckInterval)
 	}
 

go.mod

@@ -1,6 +1,6 @@
 module git.iamthefij.com/iamthefij/minitor-go
 
-go 1.17
+go 1.20
 
 require (
 	git.iamthefij.com/iamthefij/slog v1.3.0

main.go

@@ -17,6 +17,9 @@ var (
 	// Metrics contains all active metrics
 	Metrics = NewMetrics()
 
+	// PyCompat enables support for legacy Python templates
+	PyCompat = false
+
 	// version of minitor being run
 	version = "dev"
 
@@ -94,6 +97,7 @@ func main() {
 
 	flag.BoolVar(&slog.DebugLevel, "debug", false, "Enables debug logs (default: false)")
 	flag.BoolVar(&ExportMetrics, "metrics", false, "Enables prometheus metrics exporting (default: false)")
+	flag.BoolVar(&PyCompat, "py-compat", false, "Enables support for legacy Python Minitor config. Will eventually be removed. (default: false)")
 	flag.IntVar(&MetricsPort, "metrics-port", MetricsPort, "The port that Prometheus metrics should be exported on, if enabled. (default: 8080)")
 	flag.Parse()
 
@@ -120,6 +124,6 @@ func main() {
 		err = checkMonitors(&config)
 		slog.OnErrPanicf(err, "Error checking monitors")
 
-		time.Sleep(config.CheckInterval)
+		time.Sleep(config.CheckInterval.Value())
 	}
 }

monitor.go

@@ -11,9 +11,9 @@ import (
 // Monitor represents a particular periodic check of a command
 type Monitor struct { //nolint:maligned
 	// Config values
-	AlertAfter    int16         `yaml:"alert_after"`
+	AlertAfter    int16             `yaml:"alert_after"`
-	AlertEvery    *int16        `yaml:"alert_every"`
+	AlertEvery    *int16            `yaml:"alert_every"`
-	CheckInterval time.Duration `yaml:"check_interval"`
+	CheckInterval SecondsOrDuration `yaml:"check_interval"`
 	Name          string
 	AlertDown     []string `yaml:"alert_down"`
 	AlertUp       []string `yaml:"alert_up"`
@@ -45,7 +45,7 @@ func (monitor Monitor) ShouldCheck() bool {
 
 	sinceLastCheck := time.Since(monitor.lastCheck)
 
-	return sinceLastCheck >= monitor.CheckInterval
+	return sinceLastCheck >= monitor.CheckInterval.Value()
 }
 
 // Check will run the command configured by the Monitor and return a status

monitor_test.go

@@ -45,9 +45,9 @@ func TestMonitorShouldCheck(t *testing.T) {
 		name     string
 	}{
 		{Monitor{}, true, "Empty"},
-		{Monitor{lastCheck: timeNow, CheckInterval: time.Second * 15}, false, "Just checked"},
+		{Monitor{lastCheck: timeNow, CheckInterval: SecondsOrDuration{time.Second * 15}}, false, "Just checked"},
-		{Monitor{lastCheck: timeTenSecAgo, CheckInterval: time.Second * 15}, false, "-10s"},
+		{Monitor{lastCheck: timeTenSecAgo, CheckInterval: SecondsOrDuration{time.Second * 15}}, false, "-10s"},
-		{Monitor{lastCheck: timeTwentySecAgo, CheckInterval: time.Second * 15}, true, "-20s"},
+		{Monitor{lastCheck: timeTwentySecAgo, CheckInterval: SecondsOrDuration{time.Second * 15}}, true, "-20s"},
 	}
 
 	for _, c := range cases {

test/valid-config.yml

@@ -1,5 +1,5 @@
 ---
-check_interval: 1s
+check_interval: 1
 
 monitors:
   - name: Command