SMTP Mail Plugin

README.md

@@ -17,6 +17,8 @@ some officially supported implementations.
   - defines an implementation for Prometheus Alertmanager
 - [`lenses-cloudwatch-plugin`](./lenses-cloudwatch-plugin)
   - defines an implementation for CloudWatch Events
+- [`lenses-mail-alerts-plugin`](./lenses-mail-alerts-plugin)
+  - defines an implementation for SMTP emails
 
 All modules are published to Maven central. In addition, standalone JARs of 
 each of plugin integration are available to download from Github releases, ready

build.sbt

@@ -62,6 +62,7 @@ ThisBuild / publishTo := sonatypePublishTo.value
 val scalaJava8Compat = "org.scala-lang.modules" %% "scala-java8-compat" % "0.9.0"
 val sl4fj = "org.slf4j" % "slf4j-api" % "1.7.30"
 val jslack = "com.github.seratch" % "jslack" % "1.0.26"
+val mail = "javax.mail" % "mail" % "1.5.0-b01"
 val awsCloudWatchEvents = "software.amazon.awssdk" % "cloudwatchevents" % "2.9.26"
 val httpclient = "org.apache.httpcomponents" % "httpclient" % "4.5.9"
 val circeParser = "io.circe" %% "circe-parser" % "0.13.0"
@@ -74,14 +75,15 @@ val scalaTest = "org.scalatest" %% "scalatest" % "3.0.5"
 // Root project
 lazy val root = (project in file("."))
   .disablePlugins(AssemblyPlugin)
-  .aggregate(alertsPluginApi, slackAlertsPlugin, alertManagerPlugin, cloudWatchAlertsPlugin)
+  .aggregate(alertsPluginApi, slackAlertsPlugin, alertManagerPlugin, mailAlertsPlugin, cloudWatchAlertsPlugin)
   .settings(
     name := "lenses-alerts-plugin",
     ghreleaseRepoOrg := "lensesio",
     ghreleaseNotes := identity,
     ghreleaseAssets := List(
       (slackAlertsPlugin / assembly / assemblyOutputPath).value,
       (alertManagerPlugin / assembly / assemblyOutputPath).value,
+      (mailAlertsPlugin / assembly / assemblyOutputPath).value,
       (cloudWatchAlertsPlugin / assembly / assemblyOutputPath).value,
     ),
     skip in publish := true
@@ -127,6 +129,19 @@ lazy val alertManagerPlugin = (project in file("lenses-alertmanager-plugin"))
     assembly / assemblyJarName := s"${name.value}-standalone-${version.value}.jar",
   )
 
+lazy val mailAlertsPlugin = (project in file("lenses-mail-alerts-plugin"))
+  .disablePlugins(SbtGithubReleasePlugin)
+  .dependsOn(alertsPluginApi)
+  .settings(
+    name := "lenses-mail-alerts-plugin",
+    description := "Lenses.io Mail Alerts Plugin",
+    libraryDependencies += sl4fj % Provided,
+    libraryDependencies += mail,
+    libraryDependencies += logbackClassic % Test,
+    libraryDependencies += scalaTest % Test,
+    assembly / assemblyJarName := s"${name.value}-standalone-${version.value}.jar",
+  )
+
 lazy val cloudWatchAlertsPlugin = (project in file("lenses-cloudwatch-plugin"))
   .disablePlugins(SbtGithubReleasePlugin)
   .dependsOn(alertsPluginApi)

lenses-mail-alerts-plugin/README.md

@@ -0,0 +1,56 @@
+## Lenses alert mail plugin
+
+This is a Lenses plugin allowing to send Lenses raised alerts by email.
+
+### Configuration
+
+In order to enable the plugin, the following settings have to be set in Lenses:
+
+```
+    lenses.alerting.plugins = [
+      {
+        class=io.lenses.alerting.plugin.mail.MailAlertPlugin
+        config={
+           key1=value1
+           key2=value2
+           ...
+        }
+      }
+    ]
+```
+
+Available configuration options:
+
+ |Configuration    | Type   | Description                                                        |
+ |-----------------|--------|--------------------------------------------------------------------|
+ | from-address    | String | The sender mail address.                                           |
+ | email-addresses | String | Comma separated address strings in RFC822 format.                  |
+ | username        | String | The user name.                                                     |
+ | password        | String | The password.                                                      |
+ | smtp-host       | String | Host name of the SMTP mail server.                                 |
+ | smtp-port       | String | Port of the SMTP mail server.                                      |
+ | smtp-auth       | String | If true, attempt to authenticate the user using the AUTH command.  |
+ | smtp-starttls   | String | If true, enables the use of the STARTTLS command.                  |
+
+
+
+Google SMTP server example:
+
+```
+    lenses.alerting.plugins = [
+      {
+        class=io.lenses.alerting.plugin.mail.MailAlertPlugin
+        config={
+          from-address="[email protected]"
+          email-addresses="[email protected], [email protected]"
+          username="user"
+          password="passwd"  // Generate application-specific password as described here: https://support.google.com/mail/?p=InvalidSecondFactor
+          smtp-host="smtp.gmail.com"
+          smtp-port="587"
+          smtp-auth="true"
+          smtp-starttls="true"
+        }
+      }
+    ]
+```
+

lenses-mail-alerts-plugin/src/main/scala/io/lenses/alerting/plugin/mail/MailAlertConfig.scala

@@ -0,0 +1,9 @@
+package io.lenses.alerting.plugin.mail
+
+import java.util.Properties
+
+case class MailAlertConfig(senderAddress: String,
+                           emailAddresses: String,
+                           user: String,
+                           passwd: String,
+                           mailProps: Properties)

lenses-mail-alerts-plugin/src/main/scala/io/lenses/alerting/plugin/mail/MailAlertPlugin.scala

@@ -0,0 +1,75 @@
+package io.lenses.alerting.plugin.mail
+
+import java.util
+import java.util.Properties
+
+import io.lenses.alerting.plugin.javaapi.util.{Try => JTry}
+import io.lenses.alerting.plugin.javaapi.{AlertingPlugin, AlertingService, ConfigEntry}
+import io.lenses.alerting.plugin.mail.MailAlertsPlugin._
+import io.lenses.alerting.plugin.mail.TryUtils.TryExtension
+
+import scala.collection.JavaConverters._
+import scala.util.Try
+
+class MailAlertPlugin extends AlertingPlugin with Metadata {
+
+  override val name: String = "Mail"
+
+  override val description: String = "Plugin to support pushing Lenses alerts as emails"
+
+  override def init(config: util.Map[String, String]): JTry[AlertingService] = Try {
+    val map = config.asScala
+    def getOrError(key: String): String = {
+      map.getOrElse(key, throw new IllegalArgumentException(s"Invalid configuration for Mail plugin'[$key]'"))
+    }
+
+    val senderAddress = getOrError(SENDER_ADDRESS)
+    val emailAddresses = getOrError(EMAIL_ADDRESSES)
+    val username = getOrError(USERNAME)
+    val password = getOrError(PASSWORD)
+
+    def buildMailProperties = {
+      val smtpHost = getOrError(SMTP_HOST)
+      val smtpPort = getOrError(SMTP_PORT)
+      val smtpAuth = getOrError(SMTP_AUTH)
+      val smtpStartTLS = getOrError(SMTP_STARTTLS)
+
+      // https://javaee.github.io/javamail/docs/api/com/sun/mail/smtp/package-summary.html
+      val props = new Properties()
+      props.put("mail.smtp.host", smtpHost)
+      props.put("mail.smtp.port", smtpPort)
+      props.put("mail.smtp.auth", smtpAuth)
+      props.put("mail.smtp.starttls.enable", smtpStartTLS)
+      props
+    }
+
+    val props: Properties = buildMailProperties
+    val as: AlertingService = new MailAlertService(name, description, MailAlertConfig(senderAddress, emailAddresses, username, password, props))
+    as
+  }.asJava
+
+  override def configKeys(): util.List[ConfigEntry] =  {
+    import scala.collection.JavaConverters._
+    List(
+      new ConfigEntry(SENDER_ADDRESS, "The sender mail address"),
+      new ConfigEntry(EMAIL_ADDRESSES,"Comma separated address strings in RFC822 format"),
+      new ConfigEntry(USERNAME,"Username"),
+      new ConfigEntry(PASSWORD,"Password"),
+      new ConfigEntry(SMTP_HOST ,"Host name of the SMTP mail server"),
+      new ConfigEntry(SMTP_PORT,"Port of the SMTP mail server"),
+      new ConfigEntry(SMTP_AUTH,"If true, attempt to authenticate the user using the AUTH command"),
+      new ConfigEntry(SMTP_STARTTLS,"If true, enables the use of the STARTTLS command"),
+    ).asJava
+  }
+}
+
+object MailAlertsPlugin {
+  val SENDER_ADDRESS = "from-address"
+  val EMAIL_ADDRESSES = "email-addresses"
+  val USERNAME = "username"
+  val PASSWORD = "password"
+  val SMTP_HOST = "smtp-host"
+  val SMTP_PORT = "smtp-port"
+  val SMTP_AUTH = "smtp-auth"
+  val SMTP_STARTTLS = "smtp-starttls"
+}

lenses-mail-alerts-plugin/src/main/scala/io/lenses/alerting/plugin/mail/MailAlertService.scala

@@ -0,0 +1,55 @@
+package io.lenses.alerting.plugin.mail
+
+import java.sql.Timestamp
+import java.util
+import java.util.Date
+
+import io.lenses.alerting.plugin.Alert
+import io.lenses.alerting.plugin.javaapi.AlertingService
+import io.lenses.alerting.plugin.javaapi.util.{Try => JTry}
+import io.lenses.alerting.plugin.mail.TryUtils.TryExtension
+import javax.mail.internet.{InternetAddress, MimeMessage}
+import javax.mail.{Authenticator, Message, PasswordAuthentication, Session, Transport}
+
+import scala.util.Try
+
+class MailAlertService(override val name: String,
+                       override val description: String,
+                       config: MailAlertConfig) extends AlertingService with Metadata {
+
+  val session: Session = Session.getInstance(config.mailProps, new Authenticator() {
+    override protected def getPasswordAuthentication = new PasswordAuthentication(config.user, config.passwd)
+  })
+
+  override def displayedInformation(): util.Map[String, String] = {
+    import scala.collection.JavaConverters._
+    Map("Email Addresses" -> config.emailAddresses).asJava
+  }
+
+  override def publish(alert: Alert): JTry[Alert] = {
+    Try {
+      val message = new MimeMessage(session)
+      message.setFrom(new InternetAddress(config.senderAddress))
+      message.setRecipients(Message.RecipientType.TO, config.emailAddresses)
+      message.setSubject("Lenses Alert")
+      message.setSentDate(new Date())
+      message.setText(alertToText(alert))
+
+      Transport.send(message)
+      alert
+    }.asJava
+  }
+
+  private def alertToText(alert: Alert): String = {
+    val sb = new StringBuilder()
+    sb.append("AlertId: ").append(alert.alertId).append("\n")
+    sb.append("Category: ").append(alert.category).append("\n")
+    sb.append("Level: ").append(alert.level).append("\n")
+    sb.append("Timestamp: ").append(new Timestamp(alert.timestamp).toString).append("\n")
+    sb.append("Labels: ").append(alert.labels).append("\n")
+    sb.append("Tags: ").append(alert.tags).append("\n")
+    sb.append("Summary: ").append(alert.summary).append("\n")
+    alert.docs.ifPresent(docs => sb.append("Docs: ").append(docs).append("\n"))
+    sb.toString()
+  }
+}

lenses-mail-alerts-plugin/src/main/scala/io/lenses/alerting/plugin/mail/Metadata.scala

@@ -0,0 +1,6 @@
+package io.lenses.alerting.plugin.mail
+
+trait Metadata {
+  def name(): String = "Mail"
+  def description(): String = "Send an email for each Lenses alert."
+}

lenses-mail-alerts-plugin/src/main/scala/io/lenses/alerting/plugin/mail/TryUtils.scala

@@ -0,0 +1,18 @@
+package io.lenses.alerting.plugin.mail
+
+import io.lenses.alerting.plugin.javaapi.util.{Failure => JFailure, Success => JSuccess, Try => JTry}
+
+import scala.util.{Failure, Success, Try}
+
+object TryUtils {
+
+  implicit class TryExtension[T](val t: Try[T]) extends AnyVal {
+    def asJava: JTry[T] = {
+      t match {
+        case Success(value) => new JSuccess[T](value)
+        case Failure(exception) => new JFailure[T](exception)
+      }
+    }
+  }
+
+}