feature(discord): Add discord output

Co-authored-by: Thomas Labarussias <issif+github@gadz.org>

.gitignore

@@ -16,3 +16,4 @@ config.yaml
 .env
 .vscode
 .idea
+*.swp

README.md

@@ -17,6 +17,7 @@ Currently available outputs are :
 * [**Mattermost**](https://mattermost.com/)
 * [**Teams**](https://products.office.com/en-us/microsoft-teams/group-chat-software)
 * [**Datadog**](https://www.datadoghq.com/)
+* [**Discord**](https://www.discord.com/)
 * [**AlertManager**](https://prometheus.io/docs/alerting/alertmanager/)
 * [**Elasticsearch**](https://www.elastic.co/)
 * [**Loki**](https://grafana.com/oss/loki)
@@ -194,6 +195,11 @@ azure:
     # namespace: "" # The name of the space the Hub is part of
     # minimumpriority: "" # minimum priority of event for using this output, order is emergency|alert|critical|error|warning|notice|informational|debug or "" (default)
 
+discord:
+  webhookurl: "" # discord WebhookURL (ex: https://discord.com/api/webhooks/xxxxxxxxxx...), if not empty, Discord output is enabled
+  #icon: "" # Discord icon (avatar)
+  minimumpriority: "debug" # minimum priority of event for using this output, order is emergency|alert|critical|error|warning|notice|informational|debug or "" (default)
+
 ```
 
 Usage :
@@ -239,6 +245,9 @@ The *env vars* "match" field names in *yaml file with this structure (**take car
 * **DATADOG_APIKEY** : Datadog API Key, if not `empty`, Datadog output is *enabled*
 * **DATADOG_HOST** : Datadog host. Override if you are on the Datadog EU site. Defaults to american site with "https://api.datadoghq.com"
 * **DATADOG_MINIMUMPRIORITY** : minimum priority of event for using this output, order is `emergency|alert|critical|error|warning|notice|informational|debug or "" (default)`
+* **DISCORD_WEBHOOKURL** : Discord WebhookURL (ex: https://discord.com/api/webhooks/xxxxxxxxxx...), if not empty, Discord output is enabled
+* **DISCORD_ICON** : Discord icon (avatar)
+* **DISCORD_MINIMUMPRIORITY** : minimum priority of event for using use this output, order is `emergency|alert|critical|error|warning|notice|informational|debug or "" (default)`
 * **ALERTMANAGER_HOSTPORT** : AlertManager http://host:port, if not `empty`, AlertManager is *enabled*
 * **ALERTMANAGER_MINIMUMPRIORITY** : minimum priority of event for using this output, order is `emergency|alert|critical|error|warning|notice|informational|debug or "" (default)`
 * **ELASTICSEARCH_HOSTPORT** : Elasticsearch http://host:port, if not `empty`, Elasticsearch is *enabled*
@@ -407,6 +416,10 @@ time                akey    bkey    ckey    priority rule      value
 
 ![opsgenie example](https://github.com/falcosecurity/falcosidekick/raw/master/imgs/opsgenie.png)
 
+### Discord
+
+![discord example](imgs/discord_example.png)
+
 ## Development
 
 ### Build
@@ -415,6 +428,14 @@ time                akey    bkey    ckey    priority rule      value
 go build
 ```
 
+### Quicktest
+
+Create a debug event
+
+```bash
+curl -H "Content-Type: application/json" -H "Accept: application/json" localhost:2801/test
+```
+
 ### Test & Coverage
 
 ```bash

config.go

@@ -49,6 +49,9 @@ func getConfig() *types.Configuration {
 	v.SetDefault("Datadog.APIKey", "")
 	v.SetDefault("Datadog.Host", "https://api.datadoghq.com")
 	v.SetDefault("Datadog.MinimumPriority", "")
+	v.SetDefault("Discord.WebhookURL", "")
+	v.SetDefault("Discord.MinimumPriority", "")
+	v.SetDefault("Discord.Icon", "https://raw.githubusercontent.com/falcosecurity/falcosidekick/master/imgs/falcosidekick_color.png")
 	v.SetDefault("Alertmanager.HostPort", "")
 	v.SetDefault("Alertmanager.MinimumPriority", "")
 	v.SetDefault("Elasticsearch.HostPort", "")

config_example.yaml

@@ -109,3 +109,8 @@ azure:
     name: "" # Name of the Hub, if not empty, EventHub is enabled
     namespace: "" # Name of the space the Hub is in
     # minimumpriority: "" # minimum priority of event for using this output, order is emergency|alert|critical|error|warning|notice|informational|debug or "" (default)
+    #
+discord:
+  webhookurl: "" # discord WebhookURL (ex: https://discord.com/api/webhooks/xxxxxxxxxx...), if not empty, Discord output is enabled
+  #icon: "" # Discord icon (avatar)
+  minimumpriority: "debug" # minimum priority of event for using this output, order is emergency|alert|critical|error|warning|notice|informational|debug or "" (default)

handlers.go

@@ -125,6 +125,9 @@ func forwardEvent(falcopayload types.FalcoPayload) {
 	if config.Datadog.APIKey != "" && (priorityMap[strings.ToLower(falcopayload.Priority)] >= priorityMap[strings.ToLower(config.Datadog.MinimumPriority)] || falcopayload.Rule == "Test rule") {
 		go datadogClient.DatadogPost(falcopayload)
 	}
+	if config.Discord.WebhookURL != "" && (priorityMap[strings.ToLower(falcopayload.Priority)] >= priorityMap[strings.ToLower(config.Discord.MinimumPriority)] || falcopayload.Rule == "Test rule") {
+		go discordClient.DiscordPost(falcopayload)
+	}
 	if config.Alertmanager.HostPort != "" && (priorityMap[strings.ToLower(falcopayload.Priority)] >= priorityMap[strings.ToLower(config.Alertmanager.MinimumPriority)] || falcopayload.Rule == "Test rule") {
 		go alertmanagerClient.AlertmanagerPost(falcopayload)
 	}

main.go

@@ -19,6 +19,7 @@ var (
 	mattermostClient    *outputs.Client
 	teamsClient         *outputs.Client
 	datadogClient       *outputs.Client
+	discordClient       *outputs.Client
 	alertmanagerClient  *outputs.Client
 	elasticsearchClient *outputs.Client
 	influxdbClient      *outputs.Client
@@ -30,7 +31,6 @@ var (
 	webhookClient       *outputs.Client
 	azureClient         *outputs.Client
 )
-
 var statsdClient, dogstatsdClient *statsd.Client
 var config *types.Configuration
 var stats *types.Statistics
@@ -116,6 +116,15 @@ func init() {
 			enabledOutputsText += "Datadog "
 		}
 	}
+	if config.Discord.WebhookURL != "" {
+		var err error
+		discordClient, err = outputs.NewClient("Discord", config.Discord.WebhookURL, config, stats, statsdClient, dogstatsdClient)
+		if err != nil {
+			config.Discord.WebhookURL = ""
+		} else {
+			enabledOutputsText += "Discord "
+		}
+	}
 	if config.Alertmanager.HostPort != "" {
 		var err error
 		alertmanagerClient, err = outputs.NewClient("AlertManager", config.Alertmanager.HostPort+outputs.AlertmanagerURI, config, stats, statsdClient, dogstatsdClient)

outputs/discord.go

@@ -0,0 +1,110 @@
+package outputs
+
+import (
+	"github.com/falcosecurity/falcosidekick/types"
+	"strings"
+)
+
+type discordPayload struct {
+	Content    string                `json:"content"`
+	Avatar_url string                `json:"avatar_url,omitempty"`
+	Embeds     []discordEmbedPayload `json:"embeds"`
+}
+
+type discordEmbedPayload struct {
+	Title       string                     `json:"title"`
+	Url         string                     `json:"url"`
+	Description string                     `json:"description"`
+	Color       string                     `json:"color"`
+	Fields      []discordEmbedFieldPayload `json:"fields"`
+}
+
+type discordEmbedFieldPayload struct {
+	Name   string `json:"name"`
+	Value  string `json:"value"`
+	Inline bool   `json:"inline"`
+}
+
+func newDiscordPayload(falcopayload types.FalcoPayload, config *types.Configuration) discordPayload {
+	var iconURL string
+	if config.Discord.Icon != "" {
+		iconURL = config.Discord.Icon
+	} else {
+		iconURL = "https://raw.githubusercontent.com/falcosecurity/falcosidekick/master/imgs/falcosidekick.png"
+	}
+
+	var color string
+	switch strings.ToLower(falcopayload.Priority) {
+	case "emergency":
+		color = "15158332" // red
+	case "alert":
+		color = "11027200" // dark orange
+	case "critical":
+		color = "15105570" // orange
+	case "error":
+		color = "15844367" // gold
+	case "warning":
+		color = "12745742" // dark gold
+	case "notice":
+		color = "3066993" // teal
+	case "informational":
+		color = "3447003" // blue
+	case "debug":
+		color = "12370112" // light grey
+	}
+
+	embeds := make([]discordEmbedPayload, 0)
+
+	embedFields := make([]discordEmbedFieldPayload, 0)
+	var embedField discordEmbedFieldPayload
+
+	for i, j := range falcopayload.OutputFields {
+		switch j.(type) {
+		case string:
+			embedField.Name = i
+			embedField.Inline = true
+			embedField.Value = "```" + j.(string) + "```"
+		default:
+			continue
+		}
+		embedFields = append(embedFields, embedField)
+	}
+	embedField.Name = "rule"
+	embedField.Value = falcopayload.Rule
+	embedField.Inline = true
+	embedFields = append(embedFields, embedField)
+	embedField.Name = "priority"
+	embedField.Value = falcopayload.Priority
+	embedField.Inline = true
+	embedFields = append(embedFields, embedField)
+	embedField.Name = "time"
+	embedField.Value = falcopayload.Time.String()
+	embedField.Inline = true
+	embedFields = append(embedFields, embedField)
+
+	embed := discordEmbedPayload{
+		Title:       "",
+		Description: falcopayload.Output,
+		Color:       color,
+		Fields:      embedFields,
+	}
+	embeds = append(embeds, embed)
+
+	ds := discordPayload{
+		Content:    "",
+		Avatar_url: iconURL,
+		Embeds:     embeds,
+	}
+	return ds
+}
+
+// DiscordPost posts events to discord
+func (c *Client) DiscordPost(falcopayload types.FalcoPayload) {
+	err := c.Post(newDiscordPayload(falcopayload, c.Config))
+	if err != nil {
+		c.Stats.Discord.Add("error", 1)
+	} else {
+		c.Stats.Discord.Add("ok", 1)
+	}
+	c.Stats.Discord.Add("total", 1)
+}

stats.go

@@ -26,6 +26,7 @@ func getInitStats() *types.Statistics {
 		Mattermost:    expvar.NewMap("outputs.mattermost"),
 		Teams:         expvar.NewMap("outputs.teams"),
 		Datadog:       expvar.NewMap("outputs.datadog"),
+		Discord:       expvar.NewMap("outputs.discord"),
 		Alertmanager:  expvar.NewMap("outputs.alertmanager"),
 		Elasticsearch: expvar.NewMap("outputs.elasticsearch"),
 		Loki:          expvar.NewMap("outputs.loki"),
@@ -72,6 +73,9 @@ func getInitStats() *types.Statistics {
 	stats.Datadog.Add("total", 0)
 	stats.Datadog.Add("error", 0)
 	stats.Datadog.Add("ok", 0)
+	stats.Discord.Add("total", 0)
+	stats.Discord.Add("error", 0)
+	stats.Discord.Add("ok", 0)
 	stats.Alertmanager.Add("total", 0)
 	stats.Alertmanager.Add("error", 0)
 	stats.Alertmanager.Add("ok", 0)

types/types.go

@@ -24,6 +24,7 @@ type Configuration struct {
 	Rocketchat    rocketchatOutputConfig
 	Teams         teamsOutputConfig
 	Datadog       datadogOutputConfig
+	Discord       discordOutputConfig
 	Alertmanager  alertmanagerOutputConfig
 	Elasticsearch elasticsearchOutputConfig
 	Influxdb      influxdbOutputConfig
@@ -82,6 +83,12 @@ type datadogOutputConfig struct {
 	MinimumPriority string
 }
 
+type discordOutputConfig struct {
+	WebhookURL      string
+	MinimumPriority string
+	Icon            string
+}
+
 type alertmanagerOutputConfig struct {
 	HostPort        string
 	MinimumPriority string
@@ -181,6 +188,7 @@ type Statistics struct {
 	Rocketchat    *expvar.Map
 	Teams         *expvar.Map
 	Datadog       *expvar.Map
+	Discord       *expvar.Map
 	Alertmanager  *expvar.Map
 	Elasticsearch *expvar.Map
 	Loki          *expvar.Map