Clean up code and update docs

This commit is contained in:
IamTheFij 2019-10-02 16:09:11 -07:00
parent 7b746ed62a
commit ba33071070
5 changed files with 61 additions and 22 deletions

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@ -92,5 +92,6 @@ Improvement:
- [] Implement leveled logging (maybe glog or logrus) - [] Implement leveled logging (maybe glog or logrus)
- [] Consider switching from YAML to TOML - [] Consider switching from YAML to TOML
- [] Consider value of templating vs injecting values into Env variables - [] Consider value of templating vs injecting values into Env variables
- [] Consider dropping `alert_up` and `alert_down` in favor of using Go templates that offer more control of messaging
- [] Async checking - [] Async checking
- [] Use durations rather than seconds checked in event loop - [] Use durations rather than seconds checked in event loop

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@ -8,6 +8,7 @@ import (
"time" "time"
) )
// Alert is a config driven mechanism for sending a notice
type Alert struct { type Alert struct {
Name string Name string
Command []string Command []string
@ -16,12 +17,25 @@ type Alert struct {
commandShellTemplate *template.Template commandShellTemplate *template.Template
} }
// AlertNotice captures the context for an alert to be sent
type AlertNotice struct {
MonitorName string
AlertCount int16
FailureCount int16
LastCheckOutput string
LastSuccess time.Time
IsUp bool
}
// IsValid returns a boolean indicating if the Alert has been correctly
// configured
func (alert Alert) IsValid() bool { func (alert Alert) IsValid() bool {
atLeastOneCommand := (alert.CommandShell != "" || alert.Command != nil) atLeastOneCommand := (alert.CommandShell != "" || alert.Command != nil)
atMostOneCommand := (alert.CommandShell == "" || alert.Command == nil) atMostOneCommand := (alert.CommandShell == "" || alert.Command == nil)
return atLeastOneCommand && atMostOneCommand return atLeastOneCommand && atMostOneCommand
} }
// BuildTemplates compiles command templates for the Alert
func (alert *Alert) BuildTemplates() { func (alert *Alert) BuildTemplates() {
if alert.commandTemplate == nil && alert.Command != nil { if alert.commandTemplate == nil && alert.Command != nil {
// build template // build template
@ -40,17 +54,12 @@ func (alert *Alert) BuildTemplates() {
) )
log.Printf("Template built: %v", alert.commandShellTemplate) log.Printf("Template built: %v", alert.commandShellTemplate)
} else { } else {
panic("No template provided?") panic("No template provided for alert %s", alert.Name)
} }
} }
func (alert *Alert) Send(notice AlertNotice) { // Send will send an alert notice by executing the command template
// TODO: Validate and build templates in a better place and make this immutable func (alert Alert) Send(notice AlertNotice) {
if !alert.IsValid() {
log.Fatalf("Alert is invalid: %v", alert)
}
alert.BuildTemplates()
var cmd *exec.Cmd var cmd *exec.Cmd
if alert.commandTemplate != nil { if alert.commandTemplate != nil {
@ -86,12 +95,3 @@ func (alert *Alert) Send(notice AlertNotice) {
panic(err) panic(err)
} }
} }
type AlertNotice struct {
MonitorName string
AlertCount int16
FailureCount int16
LastCheckOutput string
LastSuccess time.Time
IsUp bool
}

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@ -7,12 +7,42 @@ import (
"os" "os"
) )
// Config type is contains all provided user configuration
type Config struct { type Config struct {
CheckInterval int64 `yaml:"check_interval"` CheckInterval int64 `yaml:"check_interval"`
Monitors []*Monitor Monitors []*Monitor
Alerts map[string]*Alert Alerts map[string]*Alert
} }
// IsValid checks config validity and returns true if valid
func (config Config) IsValid() (isValid bool) {
isValid = true
for _, monitor := range config.Monitors {
if !monitor.IsValid() {
log.Printf("ERROR: Invalid monitor configuration: %s", monitor.Name)
isValid = false
}
}
for _, alert := range config.Alerts {
if !alert.IsValid() {
log.Printf("ERROR: Invalid alert configuration: %s", alert.Name)
isValid = false
}
}
return
}
// Init performs extra initialization on top of loading the config from file
func (config *Config) Init() {
for name, alert := range config.Alerts {
alert.Name = name
alert.BuildTemplates()
}
}
// LoadConfig will read config from the given path and parse it
func LoadConfig(filePath string) (config Config) { func LoadConfig(filePath string) (config Config) {
data, err := ioutil.ReadFile(filePath) data, err := ioutil.ReadFile(filePath)
if err != nil { if err != nil {
@ -20,9 +50,8 @@ func LoadConfig(filePath string) (config Config) {
} }
// TODO: Decide if this is better expanded here, or only when executing // TODO: Decide if this is better expanded here, or only when executing
env_expanded := os.ExpandEnv(string(data)) envExpanded := os.ExpandEnv(string(data))
err = yaml.Unmarshal([]byte(envExpanded), &config)
err = yaml.Unmarshal([]byte(env_expanded), &config)
if err != nil { if err != nil {
log.Fatalf("ERROR: %v", err) log.Fatalf("ERROR: %v", err)
panic(err) panic(err)
@ -30,5 +59,12 @@ func LoadConfig(filePath string) (config Config) {
log.Printf("config:\n%v\n", config) log.Printf("config:\n%v\n", config)
if !config.IsValid() {
panic("Cannot continue with invalid configuration")
}
// Finish initializing configuration
config.Init()
return config return config
} }

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@ -12,6 +12,8 @@ func main() {
for _, monitor := range config.Monitors { for _, monitor := range config.Monitors {
if monitor.ShouldCheck() { if monitor.ShouldCheck() {
_, alertNotice := monitor.Check() _, alertNotice := monitor.Check()
// Should probably consider refactoring everything below here
if alertNotice != nil { if alertNotice != nil {
//log.Printf("Recieved an alert notice: %v", alertNotice) //log.Printf("Recieved an alert notice: %v", alertNotice)
var alerts []string var alerts []string

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@ -5,7 +5,7 @@ import (
"strings" "strings"
) )
/// escapeCommandShell accepts a command to be executed by a shell and escapes it // escapeCommandShell accepts a command to be executed by a shell and escapes it
func escapeCommandShell(command string) string { func escapeCommandShell(command string) string {
// Remove extra spaces and newlines from ends // Remove extra spaces and newlines from ends
command = strings.TrimSpace(command) command = strings.TrimSpace(command)
@ -15,7 +15,7 @@ func escapeCommandShell(command string) string {
return command return command
} }
/// ShellCommand takes a string and executes it as a command using `sh` // ShellCommand takes a string and executes it as a command using `sh`
func ShellCommand(command string) *exec.Cmd { func ShellCommand(command string) *exec.Cmd {
shellCommand := []string{"sh", "-c", escapeCommandShell(command)} shellCommand := []string{"sh", "-c", escapeCommandShell(command)}
//log.Printf("Shell command: %v", shellCommand) //log.Printf("Shell command: %v", shellCommand)