Fix #19: add formatting and subjects to emails

- the underlying alert struct needs to be refactored to store the raw data and let the
alerters figure out how to do the formatting.

- until it can be refactored, simple message parsing and formatting has been added to
emails.

- Fixed a few errant typos/idioms

README.md

@@ -147,7 +147,7 @@ background process as per your operating system.
 
 ### As A Systemd Service (for Linux systems with systemd)
 
-If you have a systemd based system then you can refer to [docker-alertd.service.example](https://github.com/deltaskelta/docker-alertd/blob/master/docker-alertd.service.example) 
+If you have a systemd based system then you can refer to [docker-alertd.service.example](https://github.com/deltaskelta/docker-alertd/blob/master/docker-alertd.service.example)
 the example systemd service file and this [tutorial](https://www.digitalocean.com/community/tutorials/how-to-use-systemctl-to-manage-systemd-services-and-units)
 
 ### With Launchd (MacOS)

cmd/alertd_container.go

@@ -58,7 +58,7 @@ type AlertdContainer struct {
 func (c *AlertdContainer) CheckMetrics(s *types.Stats, e error) {
 	switch {
 	case e != nil:
-		c.Alert.Add(e, nil, "Received an unknown error")
+		c.Alert.Add(e, nil, "Received an unknown error", "")
 	default:
 		if c.CPUCheck.Limit != nil {
 			c.CheckCPUUsage(s)
@@ -124,17 +124,17 @@ func (c *AlertdContainer) CheckExists(e error) {
 	switch {
 	case c.IsUnknown(e) && !c.ExistenceCheck.AlertActive:
 		// if the alert is not active I need to alert and make it active
-		c.Alert.Add(e, ErrExistCheckFail, fmt.Sprintf("%s", c.Name))
+		c.Alert.Add(e, ErrExistCheckFail, fmt.Sprintf("%s", c.Name), ErrExistCheckFail.Error())
 		c.ExistenceCheck.ToggleAlertActive()
 
 	case c.IsUnknown(e) && c.ExistenceCheck.AlertActive:
 		// do nothing
 	case c.HasErrored(e):
 		// if there is some other error besides an existence check error
-		c.Alert.Add(e, ErrUnknown, fmt.Sprintf("%s", c.Name))
+		c.Alert.Add(e, ErrUnknown, fmt.Sprintf("%s", c.Name), "")
 
 	case c.HasBecomeKnown(e):
-		c.Alert.Add(ErrExistCheckRecovered, nil, fmt.Sprintf("%s", c.Name))
+		c.Alert.Add(ErrExistCheckRecovered, nil, fmt.Sprintf("%s", c.Name), ErrExistCheckRecovered.Error())
 		c.ExistenceCheck.ToggleAlertActive()
 	default:
 		return // nothing is wrong, just keep going
@@ -152,13 +152,15 @@ func (c *AlertdContainer) CheckRunning(j *types.ContainerJSON) {
 	switch {
 	case c.ShouldAlertRunning(j) && !c.RunningCheck.AlertActive:
 		c.Alert.Add(ErrRunningCheckFail, nil, fmt.Sprintf("%s: expected running state: "+
-			"%t, current running state: %t", c.Name, *c.RunningCheck.Expected, j.State.Running))
+			"%t, current running state: %t", c.Name, *c.RunningCheck.Expected, j.State.Running),
+			ErrRunningCheckFail.Error())
 
 		c.RunningCheck.ToggleAlertActive()
 
 	case !c.ShouldAlertRunning(j) && c.RunningCheck.AlertActive:
 		c.Alert.Add(ErrRunningCheckRecovered, nil, fmt.Sprintf("%s: expected running state: "+
-			"%t, current running state: %t", c.Name, *c.RunningCheck.Expected, j.State.Running))
+			"%t, current running state: %t", c.Name, *c.RunningCheck.Expected, j.State.Running),
+			ErrRunningCheckRecovered.Error())
 
 		c.RunningCheck.ToggleAlertActive()
 	}
@@ -189,13 +191,13 @@ func (c *AlertdContainer) CheckCPUUsage(s *types.Stats) {
 	switch {
 	case a && !c.CPUCheck.AlertActive:
 		c.Alert.Add(ErrCPUCheckFail, nil, fmt.Sprintf("%s: CPU limit: %d, current usage: %d",
-			c.Name, c.CPUCheck.Limit, u))
+			c.Name, c.CPUCheck.Limit, u), ErrCPUCheckFail.Error())
 
 		c.CPUCheck.ToggleAlertActive()
 
 	case !a && c.CPUCheck.AlertActive:
 		c.Alert.Add(ErrCPUCheckRecovered, nil, fmt.Sprintf("%s: CPU limit: %d, current usage %d",
-			c.Name, c.CPUCheck.Limit, u))
+			c.Name, c.CPUCheck.Limit, u), ErrCPUCheckRecovered.Error())
 
 		c.CPUCheck.ToggleAlertActive()
 	}
@@ -215,13 +217,13 @@ func (c *AlertdContainer) CheckMinPids(s *types.Stats) {
 		// do nothing because the check is disabled
 	case a && !c.PIDCheck.AlertActive:
 		c.Alert.Add(ErrMinPIDCheckFail, nil, fmt.Sprintf("%s: minimum PIDs: %d, current PIDs: %d",
-			c.Name, c.PIDCheck.Limit, s.PidsStats.Current))
+			c.Name, c.PIDCheck.Limit, s.PidsStats.Current), ErrMinPIDCheckFail.Error())
 
 		c.PIDCheck.ToggleAlertActive()
 
 	case !a && c.PIDCheck.AlertActive:
 		c.Alert.Add(ErrMinPIDCheckRecovered, nil, fmt.Sprintf("%s: minimum PIDs: %d, current PIDs: %d",
-			c.Name, c.PIDCheck.Limit, s.PidsStats.Current))
+			c.Name, c.PIDCheck.Limit, s.PidsStats.Current), ErrMinPIDCheckRecovered.Error())
 
 		c.PIDCheck.ToggleAlertActive()
 	}
@@ -251,13 +253,13 @@ func (c *AlertdContainer) CheckMemory(s *types.Stats) {
 		// do nothing because the check is disabled
 	case a && !c.MemCheck.AlertActive:
 		c.Alert.Add(ErrMemCheckFail, nil, fmt.Sprintf("%s: Memory limit: %d, current usage: %d",
-			c.Name, c.MemCheck.Limit, u))
+			c.Name, c.MemCheck.Limit, u), ErrMemCheckFail.Error())
 
 		c.MemCheck.ToggleAlertActive()
 
 	case !a && c.MemCheck.AlertActive:
 		c.Alert.Add(ErrMemCheckRecovered, nil, fmt.Sprintf("%s: Memory limit: %d, current usage: %d",
-			c.Name, c.MemCheck.Limit, u))
+			c.Name, c.MemCheck.Limit, u), ErrMemCheckRecovered.Error())
 
 		c.MemCheck.ToggleAlertActive()
 	}

cmd/alerters.go

@@ -33,11 +33,20 @@ type Email struct {
 // Alert sends an email alert
 func (e Email) Alert(a *Alert) error {
 	// alerts in string form
-	alerts := a.Dump()
+	alerts := a.DumpEmail()
+
+	subject := e.Subject + ": "
+	for i := range a.SubjectAddendums {
+		// add addendums to the subject
+		subject += fmt.Sprintf("%s ", a.SubjectAddendums[i])
+		if i == 2 { // subjects cannot be too long, stop if it is at position 3
+			subject += fmt.Sprintf("...")
+		}
+	}
 
 	// The email message formatted properly
 	formattedMsg := []byte(fmt.Sprintf("To: %s\r\nSubject: %s\r\n\r\n%s\r\n",
-		e.To, e.Subject, alerts))
+		e.To, subject, alerts))
 
 	// Set up authentication/address information
 	auth := smtp.PlainAuth("", e.From, e.Password, e.SMTP)
@@ -140,9 +149,9 @@ func (s Slack) Alert(a *Alert) error {
 
 // Pushover contains all info needed to push a notification to Pushover api
 type Pushover struct {
-	ApiToken string
-	UserKey string
-	ApiURL string
+	APIToken string
+	UserKey  string
+	APIURL   string
 }
 
 // Valid returns an error if pushover settings are invalid
@@ -153,16 +162,16 @@ func (p Pushover) Valid() error {
 		return nil // assume that pushover was omitted
 	}
 
-	if p.ApiToken == "" {
-		errString = append(errString, ErrPushoverApiToken.Error())
+	if p.APIToken == "" {
+		errString = append(errString, ErrPushoverAPIToken.Error())
 	}
 
 	if p.UserKey == "" {
 		errString = append(errString, ErrPushoverUserKey.Error())
 	}
 
-	if p.ApiURL == "" {
-		errString = append(errString, ErrPushoverApiURL.Error())
+	if p.APIURL == "" {
+		errString = append(errString, ErrPushoverAPIURL.Error())
 	}
 
 	if len(errString) == 0 {
@@ -176,13 +185,14 @@ func (p Pushover) Valid() error {
 }
 
 // Alert sends the alert to Pushover API
-func (s Pushover) Alert(a *Alert) error {
+func (p Pushover) Alert(a *Alert) error {
 	alerts := a.Dump()
 
-	parsed_body := fmt.Sprintf("token=%s&user=%s&message=%s", s.ApiToken, s.UserKey, url.QueryEscape(alerts))
-	body := bytes.NewBufferString(parsed_body)
+	parsedBody := fmt.Sprintf("token=%s&user=%s&message=%s", p.APIToken, p.UserKey,
+		url.QueryEscape(alerts))
+	body := bytes.NewBufferString(parsedBody)
 
-	resp, err := http.Post(s.ApiURL, "application/x-www-form-urlencoded", body)
+	resp, err := http.Post(p.APIURL, "application/x-www-form-urlencoded", body)
 	if err != nil {
 		return err
 	}

cmd/errors.go

@@ -8,15 +8,15 @@ import (
 
 // these errors are for the purpose of being able to compare them later
 var (
-	ErrEmptyConfig           = errors.New("The configuration is completely empty (check config file)")
+	ErrEmptyConfig           = errors.New("the configuration is completely empty (check config file)")
 	ErrEmailNoSMTP           = errors.New("no email SMTP server")
 	ErrEmailNoTo             = errors.New("no email to addresses")
 	ErrEmailNoFrom           = errors.New("no email from addresses")
 	ErrEmailNoPass           = errors.New("no email password")
 	ErrEmailNoPort           = errors.New("no email port")
 	ErrEmailNoSubject        = errors.New("no email subject")
 	ErrSlackNoWebHookURL     = errors.New("no slack webhook url")
-	ErrNoContainers          = errors.New("There were no containers found in the configuration file")
+	ErrNoContainers          = errors.New("there were no containers found in the configuration file")
 	ErrExistCheckFail        = errors.New("Existence check failure")
 	ErrExistCheckRecovered   = errors.New("Existence check recovered")
 	ErrRunningCheckFail      = errors.New("Running check failure")
@@ -30,9 +30,9 @@ var (
 	ErrMaxPIDCheckFail       = errors.New("Max PID check Failure")
 	ErrMaxPIDCheckRecovered  = errors.New("Max PID check recovered")
 	ErrUnknown               = errors.New("Received an unknown error")
-	ErrPushoverApiToken     = errors.New("no pushover api token")
-	ErrPushoverUserKey     = errors.New("no pushover user key")
-	ErrPushoverApiURL     = errors.New("no pushover api url")
+	ErrPushoverAPIToken      = errors.New("no pushover api token")
+	ErrPushoverUserKey       = errors.New("no pushover user key")
+	ErrPushoverAPIURL        = errors.New("no pushover api url")
 )
 
 // ErrContainsErr returns true if the error string contains the message

cmd/types.go

@@ -3,6 +3,7 @@ package cmd
 import (
 	"fmt"
 	"log"
+	"strings"
 
 	"github.com/pkg/errors"
 )
@@ -16,7 +17,8 @@ type Evaluator interface {
 // Alert is the struct that stores information about alerts and its methods satisfy the
 // Alerter interface
 type Alert struct {
-	Messages []error
+	Messages         []error
+	SubjectAddendums []string
 }
 
 // ShouldSend returns true if there is an alert message to be sent
@@ -37,7 +39,9 @@ func (a *Alert) Len() int {
 }
 
 // Add should take in an error and wrap it
-func (a *Alert) Add(e1, e2 error, s string) {
+func (a *Alert) Add(e1, e2 error, s, subAddendum string) {
+
+	a.SubjectAddendums = append(a.SubjectAddendums, subAddendum)
 
 	e := e1
 	if e2 != nil {
@@ -54,6 +58,10 @@ func (a *Alert) Concat(b ...*Alert) {
 		for _, msg := range v.Messages {
 			a.Messages = append(a.Messages, msg)
 		}
+
+		for _, addendum := range v.SubjectAddendums {
+			a.SubjectAddendums = append(a.SubjectAddendums, addendum)
+		}
 	}
 }
 
@@ -68,6 +76,7 @@ func (a *Alert) Log() {
 // Clear will reset the alert to an empty string
 func (a *Alert) Clear() {
 	a.Messages = []error{}
+	a.SubjectAddendums = []string{}
 }
 
 // Dump takes the slice of alerts and dumps them to a single string
@@ -79,6 +88,26 @@ func (a *Alert) Dump() string {
 	return s
 }
 
+// DumpEmail behaves like dump, but formats them for email by splitting on ":" and adding
+// \n\t (newline and tab) for the first two segments and joining the last segment. This
+// should result in an email that is formatted as follows...
+// [containerName]:
+// 		[alertName]:
+// 		Error: [errString]
+func (a *Alert) DumpEmail() (s string) {
+	for _, e := range a.Messages {
+		errString := e.Error()
+		splitErr := strings.SplitN(errString, ":", 3)
+
+		for _, v := range splitErr {
+			s += fmt.Sprintf("%s\n\t", v)
+		}
+		s += fmt.Sprintf("\n\n")
+
+	}
+	return s
+}
+
 // Send is for sending out alerts to syslog and to alerts that are active in conf
 func (a *Alert) Send(b []Alerter) {
 	a.Log()

cmd/version.go

@@ -7,7 +7,7 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var version = "Version 0.4.3"
+var version = "Version 0.4.4"
 
 // versionCmd represents the version command
 var versionCmd = &cobra.Command{