jiralert: Improved docs and config.

README.md

@@ -52,9 +52,19 @@ $ curl -H "Content-type: application/json" -X POST \
 
 ## Configuration
 
-The configuration file is essentially a list of receivers matching 1-to-1 all Alertmanager receivers using JIRAlert; plus defaults (in the form of a partially defined receiver); and a pointer to the template file.
+The configuration file is essentially a list of JiraAlert receivers plus defaults (in the form of a partially defined receiver); and a pointer to the template file.
 
-Each receiver must have a unique name (matching the Alertmanager receiver name), JIRA API access fields (URL, username and password), a handful of required issue fields (such as the JIRA project and issue summary), some optional issue fields (e.g. priority) and a `fields` map for other (standard or custom) JIRA fields. Most of these may use [Go templating](https://golang.org/pkg/text/template/) to generate the actual field values based on the contents of the Alertmanager notification. The exact same data structures and functions as those defined in the [Alertmanager template reference](https://prometheus.io/docs/alerting/notifications/) are available in JIRAlert.
+You can find more docs in [the configuration itself](/pkg/config/config.go)
+
+Each receiver must have:
+* a unique name (matching the Alertmanager receiver name)
+* JIRA API access fields (URL, username and password),
+* handful of required issue fields (such as the JIRA project and issue summary), 
+* some optional issue fields (e.g. priority) and a `fields` map for other (standard or custom) JIRA fields. 
+
+Most of these may use [Go templating](https://golang.org/pkg/text/template/) to generate the actual field values based on the contents of the Alertmanager notification. 
+
+The exact same data structures and functions as those defined in the [Alertmanager template reference](https://prometheus.io/docs/alerting/notifications/) are available in JIRAlert.
 
 ## Alertmanager configuration
 

cmd/jiralert/content.go

@@ -53,11 +53,6 @@ const (
       <h2>Configuration</h2>
       <pre>{{ .Config }}</pre>
     {{- end }}
-
-    {{ define "content.error" -}}
-      <h2>Error</h2>
-      <pre>{{ .Err }}</pre>
-    {{- end }}
     `
 )
 
@@ -66,16 +61,12 @@ type tdata struct {
 
 	// `/config` only
 	Config string
-
-	// `/error` only
-	Err error
 }
 
 var (
 	allTemplates   = template.Must(template.New("").Parse(templates))
 	homeTemplate   = pageTemplate("home")
 	configTemplate = pageTemplate("config")
-	// errorTemplate  = pageTemplate("error")
 )
 
 func pageTemplate(name string) *template.Template {
@@ -86,7 +77,7 @@ func pageTemplate(name string) *template.Template {
 // HomeHandlerFunc is the HTTP handler for the home page (`/`).
 func HomeHandlerFunc() func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
-		homeTemplate.Execute(w, &tdata{
+		_ = homeTemplate.Execute(w, &tdata{
 			DocsUrl: docsUrl,
 		})
 	}
@@ -95,19 +86,9 @@ func HomeHandlerFunc() func(http.ResponseWriter, *http.Request) {
 // ConfigHandlerFunc is the HTTP handler for the `/config` page. It outputs the configuration marshaled in YAML format.
 func ConfigHandlerFunc(config *config.Config) func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
-		configTemplate.Execute(w, &tdata{
+		_ = configTemplate.Execute(w, &tdata{
 			DocsUrl: docsUrl,
 			Config:  config.String(),
 		})
 	}
 }
-
-// HandleError is an error handler that other handlers defer to in case of error. It is important to not have written
-// anything to w before calling HandleError(), or the 500 status code won't be set (and the content might be mixed up).
-//func HandleError(err error, metricsPath string, w http.ResponseWriter, r *http.Request) {
-//	w.WriteHeader(http.StatusInternalServerError)
-//	errorTemplate.Execute(w, &tdata{
-//		DocsUrl: docsUrl,
-//		Err:     err,
-//	})
-//}

cmd/jiralert/main.go

@@ -48,21 +48,21 @@ func main() {
 	var logger = setupLogger(*logLevel, *logFormat)
 	level.Info(logger).Log("msg", "starting JIRAlert", "version", Version)
 
-	config, _, err := config.LoadFile(*configFile, logger)
+	cfg, _, err := config.LoadFile(*configFile, logger)
 	if err != nil {
 		level.Error(logger).Log("msg", "error loading configuration", "path", *configFile, "err", err)
 		os.Exit(1)
 	}
 
-	tmpl, err := template.LoadTemplate(config.Template, logger)
+	tmpl, err := template.LoadTemplate(cfg.Template, logger)
 	if err != nil {
-		level.Error(logger).Log("msg", "error loading templates", "path", config.Template, "err", err)
+		level.Error(logger).Log("msg", "error loading templates", "path", cfg.Template, "err", err)
 		os.Exit(1)
 	}
 
 	http.HandleFunc("/alert", func(w http.ResponseWriter, req *http.Request) {
 		level.Debug(logger).Log("msg", "handling /alert webhook request")
-		defer req.Body.Close()
+		defer func() { _ = req.Body.Close() }()
 
 		// https://godoc.org/github.com/prometheus/alertmanager/template#Data
 		data := alertmanager.Data{}
@@ -71,7 +71,7 @@ func main() {
 			return
 		}
 
-		conf := config.ReceiverByName(data.Receiver)
+		conf := cfg.ReceiverByName(data.Receiver)
 		if conf == nil {
 			errorHandler(w, http.StatusNotFound, fmt.Errorf("receiver missing: %s", data.Receiver), unknownReceiver, &data, logger)
 			return
@@ -107,7 +107,7 @@ func main() {
 	})
 
 	http.HandleFunc("/", HomeHandlerFunc())
-	http.HandleFunc("/config", ConfigHandlerFunc(config))
+	http.HandleFunc("/cfg", ConfigHandlerFunc(cfg))
 	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) { http.Error(w, "OK", http.StatusOK) })
 	http.Handle("/metrics", promhttp.Handler())
 

pkg/config/config.go

@@ -74,31 +74,52 @@ func resolveFilepaths(baseDir string, cfg *Config, logger log.Logger) {
 	cfg.Template = join(cfg.Template)
 }
 
-// ReceiverConfig is the configuration for one receiver. It has a unique name and includes API access fields (URL, user
-// and password) and issue fields (required -- e.g. project, issue type -- and optional -- e.g. priority).
+// ReceiverConfig is the configuration for one receiver.
 type ReceiverConfig struct {
+	// Name represents unique name for a receiver.
+	// If Iiralert is used with Alertmanager, name it as Alertmanager receiver that sends alert via webhook to Jiralert for
+	// desired propagation.
 	Name string `yaml:"name" json:"name"`
 
-	// API access fields
+	// APIURL specifies API URL for JIRA e.g https://<your org>.atlassian.net.
+	// Required.
 	APIURL   string `yaml:"api_url" json:"api_url"`
+	// User specifies user to pass in basicauth against JIRA.
 	User     string `yaml:"user" json:"user"`
+	// Password specifies password in baiscauth against JIRA.
 	Password Secret `yaml:"password" json:"password"`
 
-	// Required issue fields
+	// Required issue fields.
+
+	// Projects specifies in what project within  org to create/reopen JIRA issues.
 	Project     string `yaml:"project" json:"project"`
+	// IssueType specifies what type of the issue to use for new JIRA issues.
 	IssueType   string `yaml:"issue_type" json:"issue_type"`
+	// Summary specifies Golang template invocation for generating the issue summary.
 	Summary     string `yaml:"summary" json:"summary"`
+	// ReopenState specifies the state to transition into when reopening a closed issue.
+	// This state has to exists for the chosen project.
 	ReopenState string `yaml:"reopen_state" json:"reopen_state"`
+	// ReopenDuration specifies the time after being closed that an issue should be reopened, after which,
+	// a new issue is created instead. Set to large value if you always want to reopen.
+	ReopenDuration    *Duration              `yaml:"reopen_duration" json:"reopen_duration"`
+
+	// Optional issue fields.
 
-	// Optional issue fields
+	// Priority represents issue priority.
 	Priority          string                 `yaml:"priority" json:"priority"`
+	// Description specifies Golang template invocation for generating the issue description.
 	Description       string                 `yaml:"description" json:"description"`
+	// WontFixResolution specifies to not reopen issues with this resolution. Useful for silencing alerts.
 	WontFixResolution string                 `yaml:"wont_fix_resolution" json:"wont_fix_resolution"`
+	// Fields specifies standard or custom field values to set on created issue.
+	//
+	// See https://developer.atlassian.com/server/jira/platform/jira-rest-api-examples/#setting-custom-field-data-for-other-field-types for further examples.
 	Fields            map[string]interface{} `yaml:"fields" json:"fields"`
+	// Components specifies issue components. Sometimes required, depending on JIRA project.
 	Components        []string               `yaml:"components" json:"components"`
-	ReopenDuration    *Duration              `yaml:"reopen_duration" json:"reopen_duration"`
-
-	// Label copy settings
+	// AddGroupLabels specifies if all Prometheus labels should be copied into separate JIRA labels.
+	// Default: false.
 	AddGroupLabels bool `yaml:"add_group_labels" json:"add_group_labels"`
 
 	// Catches all undefined fields and must be empty after parsing.
@@ -123,8 +144,13 @@ func (rc *ReceiverConfig) UnmarshalYAML(unmarshal func(interface{}) error) error
 
 // Config is the top-level configuration for JIRAlert's config file.
 type Config struct {
+	// Default specifies default values to be used in place of any ReceiverConfig' empty field.
 	Defaults  *ReceiverConfig   `yaml:"defaults,omitempty" json:"defaults,omitempty"`
+
+	// Receivers contains configuration per each receiver.
 	Receivers []*ReceiverConfig `yaml:"receivers,omitempty" json:"receivers,omitempty"`
+
+	// Template specifies an optional file with template definitions.
 	Template  string            `yaml:"template" json:"template"`
 
 	// Catches all undefined fields and must be empty after parsing.
@@ -232,10 +258,6 @@ func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		return fmt.Errorf("no receivers defined")
 	}
 
-	if c.Template == "" {
-		return fmt.Errorf("missing template file")
-	}
-
 	return checkOverflow(c.XXX, "config")
 }
 

pkg/template/template.go

@@ -32,13 +32,19 @@ var funcs = template.FuncMap{
 }
 
 // LoadTemplate reads and parses all templates defined in the given file and constructs a jiralert.Template.
+// If file is empty, or no file is passed, empty file template is returned.
 func LoadTemplate(path string, logger log.Logger) (*Template, error) {
-	level.Debug(logger).Log("msg", "loading templates", "path", path)
-	tmpl, err := template.New("").Option("missingkey=zero").Funcs(funcs).ParseFiles(path)
-	if err != nil {
-		return nil, err
+	if len(path) > 0 {
+		level.Debug(logger).Log("msg", "loading templates", "path", path)
+		tmpl, err := template.New("").Option("missingkey=zero").Funcs(funcs).ParseFiles(path)
+		if err != nil {
+			return nil, err
+		}
+		return &Template{tmpl: tmpl}, nil
 	}
-	return &Template{tmpl: tmpl}, nil
+
+	level.Info(logger).Log("msg", "no template was passed.")
+	return &Template{tmpl: template.New("")}, nil
 }
 
 func (t *Template) Err() error {