Add string-based For field and convert from ForDuration

Author: alexweav

alerting_alert_rule.go

@@ -22,7 +22,8 @@ type AlertRule struct {
 	Title        string            `json:"title"`
 	UID          string            `json:"uid,omitempty"`
 	Updated      time.Time         `json:"updated"`
-	ForDuration  time.Duration     `json:"for"`
+	For          string            `json:"for"`
+	ForDuration  time.Duration     `json:"-"`
 	Provenance   string            `json:"provenance"`
 }
 
@@ -82,6 +83,7 @@ func (c *Client) AlertRuleGroup(folderUID string, name string) (RuleGroup, error
 
 // SetAlertRuleGroup overwrites an existing rule group on the server.
 func (c *Client) SetAlertRuleGroup(group RuleGroup) error {
+	syncCalculatedRuleGroupFields(&group)
 	folderUID := group.FolderUID
 	name := group.Title
 	req, err := json.Marshal(group)
@@ -95,6 +97,7 @@ func (c *Client) SetAlertRuleGroup(group RuleGroup) error {
 
 // NewAlertRule creates a new alert rule and returns its UID.
 func (c *Client) NewAlertRule(ar *AlertRule) (string, error) {
+	syncCalculatedRuleFields(ar)
 	req, err := json.Marshal(ar)
 	if err != nil {
 		return "", err
@@ -109,6 +112,7 @@ func (c *Client) NewAlertRule(ar *AlertRule) (string, error) {
 
 // UpdateAlertRule replaces an alert rule, identified by the alert rule's UID.
 func (c *Client) UpdateAlertRule(ar *AlertRule) error {
+	syncCalculatedRuleFields(ar)
 	uri := fmt.Sprintf("/api/v1/provisioning/alert-rules/%s", ar.UID)
 	req, err := json.Marshal(ar)
 	if err != nil {
@@ -123,3 +127,50 @@ func (c *Client) DeleteAlertRule(uid string) error {
 	uri := fmt.Sprintf("/api/v1/provisioning/alert-rules/%s", uid)
 	return c.request("DELETE", uri, nil, nil, nil)
 }
+
+func syncCalculatedRuleGroupFields(group *RuleGroup) {
+	for i := range group.Rules {
+		syncCalculatedRuleFields(&group.Rules[i])
+	}
+}
+
+func syncCalculatedRuleFields(rule *AlertRule) {
+	// rule.For is the newer field. Older systems may not provide the value.
+	// If the user provided a For, prefer that over whatever we might calculate.
+	// Otherwise, translate the time.Duration-based field to the format that the rule API expects.
+	if rule.For == "" {
+		rule.For = timeDurationToRuleDuration(rule.ForDuration)
+	}
+}
+
+// timeDurationToRuleDuration converts a typical time.Duration to the string-based format that alert rules expect.
+func timeDurationToRuleDuration(d time.Duration) string {
+	ms := int64(d / time.Millisecond)
+	if ms == 0 {
+		return "0s"
+	}
+
+	r := ""
+	f := func(unit string, mult int64, exact bool) {
+		if exact && ms%mult != 0 {
+			return
+		}
+		if v := ms / mult; v > 0 {
+			r += fmt.Sprintf("%d%s", v, unit)
+			ms -= v * mult
+		}
+	}
+
+	// Only format years and weeks if the remainder is zero, as it is often
+	// easier to read 90d than 12w6d.
+	f("y", 1000*60*60*24*365, true)
+	f("w", 1000*60*60*24*7, true)
+
+	f("d", 1000*60*60*24, false)
+	f("h", 1000*60*60, false)
+	f("m", 1000*60, false)
+	f("s", 1000, false)
+	f("ms", 1, false)
+
+	return r
+}

alerting_alert_rule_test.go

@@ -3,6 +3,7 @@ package gapi
 import (
 	"encoding/json"
 	"testing"
+	"time"
 
 	"github.com/gobs/pretty"
 )
@@ -138,7 +139,7 @@ func createAlertRule() AlertRule {
 		OrgID:        1,
 		RuleGroup:    "eval_group_1",
 		Title:        "Always in alarm",
-		ForDuration:  0,
+		ForDuration:  60 * time.Second,
 	}
 }
 
@@ -165,7 +166,7 @@ const writeAlertRuleJSON = `
 	"orgId": 1,
 	"ruleGroup": "eval_group_1",
 	"title": "Always in alarm",
-	"for": 0
+	"for": "1m"
 }
 `
 
@@ -180,7 +181,7 @@ const getAlertRuleJSON = `
 	"uid": "123abcd",
 	"ruleGroup": "eval_group_1",
 	"title": "Always in alarm",
-	"for": 0
+	"for": "1m"
 }
 `
 
@@ -266,7 +267,7 @@ const getAlertRuleGroupJSON = `
 			"RuleGroupIndex": 1,
 			"NoDataState": "NoData",
 			"ExecErrState": "Alerting",
-			"For": 300000000000,
+			"For": "1m",
 			"Annotations": {},
 			"Labels": {}
 		}