Parse config in a way that is compatible with the Mimir Alertmanager (g…

…rafana#194)

definition/alertmanager.go

@@ -135,12 +135,6 @@ func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		return err
 	}
 
-	// Having a nil global config causes panics in the Alertmanager codebase.
-	if c.Global == nil {
-		c.Global = &config.GlobalConfig{}
-		*c.Global = config.DefaultGlobalConfig()
-	}
-
 	if c.Route == nil {
 		return fmt.Errorf("no routes provided")
 	}

definition/compat.go

@@ -2,11 +2,220 @@ package definition
 
 import (
 	"encoding/json"
+	"fmt"
+	"strings"
 
 	"github.com/grafana/alerting/notify"
 	"github.com/prometheus/alertmanager/config"
+	"gopkg.in/yaml.v3"
 )
 
+// LoadCompat loads a PostableApiAlertingConfig from a YAML configuration
+// and runs validations to ensure that it works with the Mimir Alertmanager.
+func LoadCompat(rawCfg []byte) (*PostableApiAlertingConfig, error) {
+	if len(rawCfg) == 0 {
+		return nil, fmt.Errorf("empty input")
+	}
+
+	var c PostableApiAlertingConfig
+	if err := yaml.Unmarshal(rawCfg, &c); err != nil {
+		return nil, err
+	}
+
+	// Having a nil global config causes panics in the Alertmanager codebase.
+	if c.Global == nil {
+		c.Global = &config.GlobalConfig{}
+		*c.Global = config.DefaultGlobalConfig()
+	}
+
+	// Check that the configuration for upstream receivers is well formed.
+	// Taken from https://github.com/prometheus/alertmanager/blob/e5821b78917591a5603e3e1788b6a94d5b2972e0/config/config.go#L356-L545
+	// with some modifications to ignore file-related settings.
+	names := map[string]struct{}{}
+	for _, rcv := range c.Receivers {
+		if _, ok := names[rcv.Name]; ok {
+			return nil, fmt.Errorf("notification config name %q is not unique", rcv.Name)
+		}
+		for _, wh := range rcv.WebhookConfigs {
+			if wh.HTTPConfig == nil {
+				wh.HTTPConfig = c.Global.HTTPConfig
+			}
+		}
+		for _, ec := range rcv.EmailConfigs {
+			if ec.Smarthost.String() == "" {
+				if c.Global.SMTPSmarthost.String() == "" {
+					return nil, fmt.Errorf("no global SMTP smarthost set")
+				}
+				ec.Smarthost = c.Global.SMTPSmarthost
+			}
+			if ec.From == "" {
+				if c.Global.SMTPFrom == "" {
+					return nil, fmt.Errorf("no global SMTP from set")
+				}
+				ec.From = c.Global.SMTPFrom
+			}
+			if ec.Hello == "" {
+				ec.Hello = c.Global.SMTPHello
+			}
+			if ec.AuthUsername == "" {
+				ec.AuthUsername = c.Global.SMTPAuthUsername
+			}
+			if ec.AuthPassword == "" {
+				ec.AuthPassword = c.Global.SMTPAuthPassword
+			}
+			if ec.AuthSecret == "" {
+				ec.AuthSecret = c.Global.SMTPAuthSecret
+			}
+			if ec.AuthIdentity == "" {
+				ec.AuthIdentity = c.Global.SMTPAuthIdentity
+			}
+			if ec.RequireTLS == nil {
+				ec.RequireTLS = new(bool)
+				*ec.RequireTLS = c.Global.SMTPRequireTLS
+			}
+		}
+		for _, sc := range rcv.SlackConfigs {
+			if sc.HTTPConfig == nil {
+				sc.HTTPConfig = c.Global.HTTPConfig
+			}
+			if sc.APIURL == nil {
+				if c.Global.SlackAPIURL == nil {
+					return nil, fmt.Errorf("no global Slack API URL set")
+				}
+				sc.APIURL = c.Global.SlackAPIURL
+			}
+		}
+		for _, poc := range rcv.PushoverConfigs {
+			if poc.HTTPConfig == nil {
+				poc.HTTPConfig = c.Global.HTTPConfig
+			}
+		}
+		for _, pdc := range rcv.PagerdutyConfigs {
+			if pdc.HTTPConfig == nil {
+				pdc.HTTPConfig = c.Global.HTTPConfig
+			}
+			if pdc.URL == nil {
+				if c.Global.PagerdutyURL == nil {
+					return nil, fmt.Errorf("no global PagerDuty URL set")
+				}
+				pdc.URL = c.Global.PagerdutyURL
+			}
+		}
+		for _, ogc := range rcv.OpsGenieConfigs {
+			if ogc.HTTPConfig == nil {
+				ogc.HTTPConfig = c.Global.HTTPConfig
+			}
+			if ogc.APIURL == nil {
+				if c.Global.OpsGenieAPIURL == nil {
+					return nil, fmt.Errorf("no global OpsGenie URL set")
+				}
+				ogc.APIURL = c.Global.OpsGenieAPIURL
+			}
+			if !strings.HasSuffix(ogc.APIURL.Path, "/") {
+				ogc.APIURL.Path += "/"
+			}
+			if ogc.APIKey == "" {
+				if c.Global.OpsGenieAPIKey == "" {
+					return nil, fmt.Errorf("no global OpsGenie API Key set")
+				}
+				ogc.APIKey = c.Global.OpsGenieAPIKey
+			}
+		}
+		for _, wcc := range rcv.WechatConfigs {
+			if wcc.HTTPConfig == nil {
+				wcc.HTTPConfig = c.Global.HTTPConfig
+			}
+
+			if wcc.APIURL == nil {
+				if c.Global.WeChatAPIURL == nil {
+					return nil, fmt.Errorf("no global Wechat URL set")
+				}
+				wcc.APIURL = c.Global.WeChatAPIURL
+			}
+
+			if wcc.APISecret == "" {
+				if c.Global.WeChatAPISecret == "" {
+					return nil, fmt.Errorf("no global Wechat ApiSecret set")
+				}
+				wcc.APISecret = c.Global.WeChatAPISecret
+			}
+
+			if wcc.CorpID == "" {
+				if c.Global.WeChatAPICorpID == "" {
+					return nil, fmt.Errorf("no global Wechat CorpID set")
+				}
+				wcc.CorpID = c.Global.WeChatAPICorpID
+			}
+
+			if !strings.HasSuffix(wcc.APIURL.Path, "/") {
+				wcc.APIURL.Path += "/"
+			}
+		}
+		for _, voc := range rcv.VictorOpsConfigs {
+			if voc.HTTPConfig == nil {
+				voc.HTTPConfig = c.Global.HTTPConfig
+			}
+			if voc.APIURL == nil {
+				if c.Global.VictorOpsAPIURL == nil {
+					return nil, fmt.Errorf("no global VictorOps URL set")
+				}
+				voc.APIURL = c.Global.VictorOpsAPIURL
+			}
+			if !strings.HasSuffix(voc.APIURL.Path, "/") {
+				voc.APIURL.Path += "/"
+			}
+			if voc.APIKey == "" {
+				if c.Global.VictorOpsAPIKey == "" {
+					return nil, fmt.Errorf("no global VictorOps API Key set")
+				}
+				voc.APIKey = c.Global.VictorOpsAPIKey
+			}
+		}
+		for _, sns := range rcv.SNSConfigs {
+			if sns.HTTPConfig == nil {
+				sns.HTTPConfig = c.Global.HTTPConfig
+			}
+		}
+
+		for _, telegram := range rcv.TelegramConfigs {
+			if telegram.HTTPConfig == nil {
+				telegram.HTTPConfig = c.Global.HTTPConfig
+			}
+			if telegram.APIUrl == nil {
+				telegram.APIUrl = c.Global.TelegramAPIUrl
+			}
+		}
+		for _, discord := range rcv.DiscordConfigs {
+			if discord.HTTPConfig == nil {
+				discord.HTTPConfig = c.Global.HTTPConfig
+			}
+			if discord.WebhookURL == nil {
+				return nil, fmt.Errorf("no discord webhook URL provided")
+			}
+		}
+		for _, webex := range rcv.WebexConfigs {
+			if webex.APIURL == nil {
+				if c.Global.WebexAPIURL == nil {
+					return nil, fmt.Errorf("no global Webex URL set")
+				}
+
+				webex.APIURL = c.Global.WebexAPIURL
+			}
+		}
+		for _, msteams := range rcv.MSTeamsConfigs {
+			if msteams.HTTPConfig == nil {
+				msteams.HTTPConfig = c.Global.HTTPConfig
+			}
+			if msteams.WebhookURL == nil {
+				return nil, fmt.Errorf("no msteams webhook URL provided")
+			}
+		}
+		names[rcv.Name] = struct{}{}
+	}
+
+	return &c, nil
+}
+
 // GrafanaToUpstreamConfig converts a Grafana alerting configuration into an upstream Alertmanager configuration.
 // It ignores the configuration for Grafana receivers, adding only their names.
 func GrafanaToUpstreamConfig(cfg *PostableApiAlertingConfig) config.Config {