132 lines
3.5 KiB
Go
132 lines
3.5 KiB
Go
package main
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import (
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"bytes"
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"fmt"
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"log"
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"os/exec"
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"strings"
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"text/template"
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"time"
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)
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// Alert is a config driven mechanism for sending a notice
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type Alert struct {
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Name string
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Command CommandOrShell
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commandTemplate []*template.Template
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commandShellTemplate *template.Template
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}
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// AlertNotice captures the context for an alert to be sent
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type AlertNotice struct {
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MonitorName string
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AlertCount int16
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FailureCount int16
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LastCheckOutput string
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LastSuccess time.Time
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IsUp bool
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}
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// IsValid returns a boolean indicating if the Alert has been correctly
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// configured
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func (alert Alert) IsValid() bool {
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return !alert.Command.Empty()
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}
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// BuildTemplates compiles command templates for the Alert
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func (alert *Alert) BuildTemplates() error {
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// TODO: Remove legacy template support later after 1.0
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legacy := strings.NewReplacer(
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"{alert_count}", "{{.AlertCount}}",
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"{alert_message}", "{{.MonitorName}} check has failed {{.FailureCount}} times",
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"{failure_count}", "{{.FailureCount}}",
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"{last_output}", "{{.LastCheckOutput}}",
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"{last_success}", "{{.LastSuccess}}",
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"{monitor_name}", "{{.MonitorName}}",
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)
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if LogDebug {
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log.Printf("DEBUG: Building template for alert %s", alert.Name)
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}
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if alert.commandTemplate == nil && alert.Command.Command != nil {
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alert.commandTemplate = []*template.Template{}
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for i, cmdPart := range alert.Command.Command {
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if PyCompat {
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cmdPart = legacy.Replace(cmdPart)
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}
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alert.commandTemplate = append(alert.commandTemplate, template.Must(
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template.New(alert.Name+fmt.Sprint(i)).Parse(cmdPart),
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))
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}
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} else if alert.commandShellTemplate == nil && alert.Command.ShellCommand != "" {
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shellCmd := alert.Command.ShellCommand
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if PyCompat {
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shellCmd = legacy.Replace(shellCmd)
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}
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alert.commandShellTemplate = template.Must(
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template.New(alert.Name).Parse(shellCmd),
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)
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} else {
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return fmt.Errorf("No template provided for alert %s", alert.Name)
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}
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return nil
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}
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// Send will send an alert notice by executing the command template
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func (alert Alert) Send(notice AlertNotice) (outputStr string, err error) {
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log.Printf("INFO: Sending alert %s for %s", alert.Name, notice.MonitorName)
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var cmd *exec.Cmd
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if alert.commandTemplate != nil {
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command := []string{}
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for _, cmdTmp := range alert.commandTemplate {
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var commandBuffer bytes.Buffer
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err = cmdTmp.Execute(&commandBuffer, notice)
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if err != nil {
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return
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}
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command = append(command, commandBuffer.String())
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}
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cmd = exec.Command(command[0], command[1:]...)
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} else if alert.commandShellTemplate != nil {
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var commandBuffer bytes.Buffer
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err = alert.commandShellTemplate.Execute(&commandBuffer, notice)
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if err != nil {
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return
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}
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shellCommand := commandBuffer.String()
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cmd = ShellCommand(shellCommand)
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} else {
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err = fmt.Errorf("No templates compiled for alert %v", alert.Name)
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return
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}
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// Exit if we're not ready to run the command
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if cmd == nil || err != nil {
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return
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}
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var output []byte
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output, err = cmd.CombinedOutput()
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outputStr = string(output)
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if LogDebug {
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log.Printf("DEBUG: Alert output for: %s\n---\n%s\n---", alert.Name, outputStr)
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}
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return outputStr, err
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}
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// NewLogAlert creates an alert that does basic logging using echo
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func NewLogAlert() *Alert {
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return &Alert{
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Name: "log",
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Command: CommandOrShell{
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Command: []string{
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"echo",
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"{{.MonitorName}} {{if .IsUp}}has recovered{{else}}check has failed {{.FailureCount}} times{{end}}",
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},
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},
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}
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}
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