Merge branch 'master' of github.com:thingsboard/thingsboard

@@ -17,21 +17,21 @@ package org.thingsboard.server.service.apiusage;
 
 import com.google.common.util.concurrent.FutureCallback;
 import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
-import org.springframework.boot.context.event.ApplicationReadyEvent;
 import org.springframework.context.annotation.Lazy;
-import org.springframework.context.event.EventListener;
-import org.springframework.core.annotation.Order;
-import org.springframework.data.util.Pair;
 import org.springframework.stereotype.Service;
+import org.thingsboard.rule.engine.api.MailService;
 import org.thingsboard.server.common.data.ApiFeature;
 import org.thingsboard.server.common.data.ApiUsageRecordKey;
 import org.thingsboard.server.common.data.ApiUsageState;
+import org.thingsboard.server.common.data.ApiUsageStateMailMessage;
 import org.thingsboard.server.common.data.ApiUsageStateValue;
 import org.thingsboard.server.common.data.Tenant;
 import org.thingsboard.server.common.data.TenantProfile;
+import org.thingsboard.server.common.data.exception.ThingsboardException;
 import org.thingsboard.server.common.data.id.ApiUsageStateId;
 import org.thingsboard.server.common.data.id.TenantId;
 import org.thingsboard.server.common.data.id.TenantProfileId;
@@ -45,6 +45,7 @@ import org.thingsboard.server.common.data.tenant.profile.TenantProfileData;
 import org.thingsboard.server.common.msg.queue.ServiceType;
 import org.thingsboard.server.common.msg.queue.TbCallback;
 import org.thingsboard.server.common.msg.tools.SchedulerUtils;
+import org.thingsboard.server.dao.tenant.TbTenantProfileCache;
 import org.thingsboard.server.dao.tenant.TenantService;
 import org.thingsboard.server.dao.timeseries.TimeseriesService;
 import org.thingsboard.server.dao.usagerecord.ApiUsageStateService;
@@ -54,14 +55,12 @@ import org.thingsboard.server.queue.common.TbProtoQueueMsg;
 import org.thingsboard.server.queue.discovery.PartitionChangeEvent;
 import org.thingsboard.server.queue.discovery.PartitionService;
 import org.thingsboard.server.queue.scheduler.SchedulerComponent;
-import org.thingsboard.server.queue.util.TbCoreComponent;
-import org.thingsboard.server.dao.tenant.TbTenantProfileCache;
 import org.thingsboard.server.service.queue.TbClusterService;
 import org.thingsboard.server.service.telemetry.InternalTelemetryService;
 
 import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -69,6 +68,8 @@ import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -94,6 +95,7 @@ public class DefaultTbApiUsageStateService implements TbApiUsageStateService {
     private final ApiUsageStateService apiUsageStateService;
     private final SchedulerComponent scheduler;
     private final TbTenantProfileCache tenantProfileCache;
+    private final MailService mailService;
 
     @Lazy
     @Autowired
@@ -112,13 +114,15 @@ public class DefaultTbApiUsageStateService implements TbApiUsageStateService {
 
     private final Lock updateLock = new ReentrantLock();
 
+    private final ExecutorService mailExecutor;
+
     public DefaultTbApiUsageStateService(TbClusterService clusterService,
                                          PartitionService partitionService,
                                          TenantService tenantService,
                                          TimeseriesService tsService,
                                          ApiUsageStateService apiUsageStateService,
                                          SchedulerComponent scheduler,
-                                         TbTenantProfileCache tenantProfileCache) {
+                                         TbTenantProfileCache tenantProfileCache, MailService mailService) {
         this.clusterService = clusterService;
         this.partitionService = partitionService;
         this.tenantService = tenantService;
@@ -126,6 +130,8 @@ public class DefaultTbApiUsageStateService implements TbApiUsageStateService {
         this.apiUsageStateService = apiUsageStateService;
         this.scheduler = scheduler;
         this.tenantProfileCache = tenantProfileCache;
+        this.mailService = mailService;
+        this.mailExecutor = Executors.newSingleThreadExecutor();
     }
 
     @PostConstruct
@@ -286,7 +292,49 @@ public class DefaultTbApiUsageStateService implements TbApiUsageStateService {
         List<TsKvEntry> stateTelemetry = new ArrayList<>();
         result.forEach(((apiFeature, aState) -> stateTelemetry.add(new BasicTsKvEntry(ts, new StringDataEntry(apiFeature.getApiStateKey(), aState.name())))));
         tsWsService.saveAndNotifyInternal(state.getTenantId(), state.getApiUsageState().getId(), stateTelemetry, VOID_CALLBACK);
-        //TODO: notify tenant admin via email!
+
+        String email = tenantService.findTenantById(state.getTenantId()).getEmail();
+
+        if (StringUtils.isNotEmpty(email)) {
+            result.forEach((apiFeature, stateValue) -> {
+                mailExecutor.submit(() -> {
+                    try {
+                        mailService.sendApiFeatureStateEmail(apiFeature, stateValue, email, createStateMailMessage(state, apiFeature, stateValue));
+                    } catch (ThingsboardException e) {
+                        log.warn("[{}] Can't send update of the API state to tenant with provided email [{}]", state.getTenantId(), email, e);
+                    }
+                });
+            });
+        } else {
+            log.warn("[{}] Can't send update of the API state to tenant with empty email!", state.getTenantId());
+        }
+    }
+
+    private ApiUsageStateMailMessage createStateMailMessage(TenantApiUsageState state, ApiFeature apiFeature, ApiUsageStateValue stateValue) {
+        StateChecker checker = getStateChecker(stateValue);
+        for (ApiUsageRecordKey apiUsageRecordKey : ApiUsageRecordKey.getKeys(apiFeature)) {
+            long threshold = state.getProfileThreshold(apiUsageRecordKey);
+            long warnThreshold = state.getProfileWarnThreshold(apiUsageRecordKey);
+            long value = state.get(apiUsageRecordKey);
+            if (checker.check(threshold, warnThreshold, value)) {
+                return new ApiUsageStateMailMessage(apiUsageRecordKey, threshold, value);
+            }
+        }
+        return null;
+    }
+
+    private StateChecker getStateChecker(ApiUsageStateValue stateValue) {
+        if (ApiUsageStateValue.ENABLED.equals(stateValue)) {
+            return (t, wt, v) -> true;
+        } else if (ApiUsageStateValue.WARNING.equals(stateValue)) {
+            return (t, wt, v) -> v < t && v >= wt;
+        } else {
+            return (t, wt, v) -> v >= t;
+        }
+    }
+
+    private interface StateChecker {
+        boolean check(long threshold, long warnThreshold, long value);
     }
 
     private void checkStartOfNextCycle() {
@@ -367,4 +415,10 @@ public class DefaultTbApiUsageStateService implements TbApiUsageStateService {
         }
     }
 
+    @PreDestroy
+    private void destroy() {
+        if (mailExecutor != null) {
+            mailExecutor.shutdownNow();
+        }
+    }
 }

@@ -20,6 +20,7 @@ import freemarker.template.Configuration;
 import freemarker.template.Template;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
+import org.jetbrains.annotations.NotNull;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.MessageSource;
 import org.springframework.core.NestedRuntimeException;
@@ -29,6 +30,10 @@ import org.springframework.stereotype.Service;
 import org.springframework.ui.freemarker.FreeMarkerTemplateUtils;
 import org.thingsboard.rule.engine.api.MailService;
 import org.thingsboard.server.common.data.AdminSettings;
+import org.thingsboard.server.common.data.ApiFeature;
+import org.thingsboard.server.common.data.ApiUsageRecordKey;
+import org.thingsboard.server.common.data.ApiUsageStateMailMessage;
+import org.thingsboard.server.common.data.ApiUsageStateValue;
 import org.thingsboard.server.common.data.exception.ThingsboardErrorCode;
 import org.thingsboard.server.common.data.exception.ThingsboardException;
 import org.thingsboard.server.common.data.id.EntityId;
@@ -51,6 +56,8 @@ public class DefaultMailService implements MailService {
     public static final String MAIL_PROP = "mail.";
     public static final String TARGET_EMAIL = "targetEmail";
     public static final String UTF_8 = "UTF-8";
+    public static final int _10K = 10000;
+    public static final int _1M = 1000000;
     @Autowired
     private MessageSource messages;
 
@@ -246,6 +253,108 @@ public class DefaultMailService implements MailService {
         sendMail(mailSender, mailFrom, email, subject, message);
     }
 
+    @Override
+    public void sendApiFeatureStateEmail(ApiFeature apiFeature, ApiUsageStateValue stateValue, String email, ApiUsageStateMailMessage msg) throws ThingsboardException {
+        String subject = messages.getMessage("api.usage.state", null, Locale.US);
+
+        Map<String, Object> model = new HashMap<>();
+        model.put("apiFeature", apiFeature.getLabel());
+        model.put(TARGET_EMAIL, email);
+
+        String message = null;
+
+        switch (stateValue) {
+            case ENABLED:
+                model.put("apiLabel", toEnabledValueLabel(apiFeature));
+                message = mergeTemplateIntoString("state.enabled.ftl", model);
+                break;
+            case WARNING:
+                model.put("apiValueLabel", toDisabledValueLabel(apiFeature) + " " + toWarningValueLabel(msg.getKey(), msg.getValue(), msg.getThreshold()));
+                message = mergeTemplateIntoString("state.warning.ftl", model);
+                break;
+            case DISABLED:
+                model.put("apiLimitValueLabel", toDisabledValueLabel(apiFeature) + " " + toDisabledValueLabel(msg.getKey(), msg.getThreshold()));
+                message = mergeTemplateIntoString("state.disabled.ftl", model);
+                break;
+        }
+        sendMail(mailSender, mailFrom, email, subject, message);
+    }
+
+    private String toEnabledValueLabel(ApiFeature apiFeature) {
+        switch (apiFeature) {
+            case DB:
+                return "save";
+            case TRANSPORT:
+                return "receive";
+            case JS:
+                return "invoke";
+            case RE:
+                return "process";
+            default:
+                throw new RuntimeException("Not implemented!");
+        }
+    }
+
+    private String toDisabledValueLabel(ApiFeature apiFeature) {
+        switch (apiFeature) {
+            case DB:
+                return "saved";
+            case TRANSPORT:
+                return "received";
+            case JS:
+                return "invoked";
+            case RE:
+                return "processed";
+            default:
+                throw new RuntimeException("Not implemented!");
+        }
+    }
+
+    private String toWarningValueLabel(ApiUsageRecordKey key, long value, long threshold) {
+        String valueInM = getValueAsString(value);
+        String thresholdInM = getValueAsString(threshold);
+        switch (key) {
+            case STORAGE_DP_COUNT:
+            case TRANSPORT_DP_COUNT:
+                return valueInM + " out of " + thresholdInM + " allowed data points";
+            case TRANSPORT_MSG_COUNT:
+                return valueInM + " out of " + thresholdInM + " allowed messages";
+            case JS_EXEC_COUNT:
+                return valueInM + " out of " + thresholdInM + " allowed JavaScript functions";
+            case RE_EXEC_COUNT:
+                return valueInM + " out of " + thresholdInM + " allowed Rule Engine messages";
+            default:
+                throw new RuntimeException("Not implemented!");
+        }
+    }
+
+    private String toDisabledValueLabel(ApiUsageRecordKey key, long value) {
+        switch (key) {
+            case STORAGE_DP_COUNT:
+            case TRANSPORT_DP_COUNT:
+                return getValueAsString(value) + " data points";
+            case TRANSPORT_MSG_COUNT:
+                return getValueAsString(value) + " messages";
+            case JS_EXEC_COUNT:
+                return "JavaScript functions " + getValueAsString(value) + " times";
+            case RE_EXEC_COUNT:
+                return getValueAsString(value) + " Rule Engine messages";
+            default:
+                throw new RuntimeException("Not implemented!");
+        }
+    }
+
+    @NotNull
+    private String getValueAsString(long value) {
+        if (value > _1M && value % _1M < _10K) {
+            return value / _1M + "M";
+        } else if (value > _10K) {
+            return String.format("%.2fM", ((double) value) / 1000000);
+        } else {
+            return value + "";
+        }
+    }
+
     private void sendMail(JavaMailSenderImpl mailSender,
                           String mailFrom, String email,
                           String subject, String message) throws ThingsboardException {

@@ -3,4 +3,5 @@ activation.subject=Your account activation on Thingsboard
 account.activated.subject=Thingsboard - your account has been activated
 reset.password.subject=Thingsboard - Password reset has been requested
 password.was.reset.subject=Thingsboard - your account password has been reset
-account.lockout.subject=Thingsboard - User account has been lockout
\ No newline at end of file
+account.lockout.subject=Thingsboard - User account has been lockout
+api.usage.state=Thingsboard - Api Usage State for tenant has been updated
\ No newline at end of file

+<#--
+
+    Copyright © 2016-2020 The Thingsboard Authors
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+-->
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml"
+      style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+<head>
+    <meta name="viewport" content="width=device-width"/>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+    <title>Thingsboard - Api Usage State</title>
+
+
+    <style type="text/css">
+        img {
+            max-width: 100%;
+        }
+
+        body {
+            -webkit-font-smoothing: antialiased;
+            -webkit-text-size-adjust: none;
+            width: 100% !important;
+            height: 100%;
+            line-height: 1.6em;
+        }
+
+        body {
+            background-color: #f6f6f6;
+        }
+
+        @media only screen and (max-width: 640px) {
+            body {
+                padding: 0 !important;
+            }
+
+            h1 {
+                font-weight: 800 !important;
+                margin: 20px 0 5px !important;
+            }
+
+            h2 {
+                font-weight: 800 !important;
+                margin: 20px 0 5px !important;
+            }
+
+            h3 {
+                font-weight: 800 !important;
+                margin: 20px 0 5px !important;
+            }
+
+            h4 {
+                font-weight: 800 !important;
+                margin: 20px 0 5px !important;
+            }
+
+            h1 {
+                font-size: 22px !important;
+            }
+
+            h2 {
+                font-size: 18px !important;
+            }
+
+            h3 {
+                font-size: 16px !important;
+            }
+
+            .container {
+                padding: 0 !important;
+                width: 100% !important;
+            }
+
+            .content {
+                padding: 0 !important;
+            }
+
+            .content-wrap {
+                padding: 10px !important;
+            }
+
+            .invoice {
+                width: 100% !important;
+            }
+        }
+    </style>
+</head>
+
+<body itemscope itemtype="http://schema.org/EmailMessage"
+      style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; -webkit-font-smoothing: antialiased; -webkit-text-size-adjust: none; width: 100% !important; height: 100%; line-height: 1.6em; background-color: #f6f6f6; margin: 0;"
+      bgcolor="#f6f6f6">
+
+<table class="main"
+       style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; box-sizing: border-box; border-radius: 3px; width: 100%; background-color: #f6f6f6; margin: 0px auto;"
+       cellspacing="0" cellpadding="0" bgcolor="#f6f6f6">
+    <tbody>
+    <tr style="box-sizing: border-box; margin: 0px;">
+        <td class="content-wrap" style="box-sizing: border-box; vertical-align: top; margin: 0px; padding: 20px;"
+            align="center" valign="top">
+            <table style="box-sizing: border-box; border: 1px solid #e9e9e9; border-radius: 3px; margin: 0px; height: 223px; padding: 20px; background-color: #ffffff; width: 600px; max-width: 600px !important;"
+                   width="600" cellspacing="0" cellpadding="0">
+                <tbody>
+                <tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+                    <td class="content-block"
+                        style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; color: #348eda; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 84px;"
+                        valign="top">
+                        <h2>Your ThingsBoard account feature was disabled</h2>
+                    </td>
+                </tr>
+                <tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+                    <td class="content-block"
+                        style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 40px;"
+                        valign="top">We have disabled the ${apiFeature} for your account because ThingsBoard has already ${apiLimitValueLabel}.
+                    </td>
+                </tr>
+                <tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+                    <td class="content-block"
+                        style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 59px;"
+                        valign="top">Please contact your system administrator to resolve the issue.
+                    </td>
+                </tr>
+                <tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+                    <td class="content-block"
+                        style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 40px;"
+                        valign="top">&mdash; The ThingsBoard
+                    </td>
+                </tr>
+                </tbody>
+            </table>
+        </td>
+    </tr>
+    </tbody>
+</table>
+<table style="color: #999999; font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; box-sizing: border-box; margin: 0px auto; height: 64px; background-color: #f6f6f6; width: 100%;"
+       cellpadding="0px 0px 20px">
+    <tbody>
+    <tr style="box-sizing: border-box; margin: 0px;">
+        <td class="aligncenter content-block"
+            style="box-sizing: border-box; font-size: 12px; margin: 0px; padding: 0px 0px 20px; width: 600px; text-align: center; vertical-align: middle;"
+            align="center" valign="top">This email was sent to&nbsp;<a
+                    style="box-sizing: border-box; color: #999999; margin: 0px;"
+                    href="mailto:${targetEmail}">${targetEmail}</a>&nbsp;by ThingsBoard.
+        </td>
+    </tr>
+    </tbody>
+</table>
+</body>
+</html>

+<#--
+
+    Copyright © 2016-2020 The Thingsboard Authors
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+-->
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+		"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml"
+	  style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+<head>
+	<meta name="viewport" content="width=device-width"/>
+	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+	<title>Thingsboard - Api Usage State</title>
+
+
+	<style type="text/css">
+		img {
+			max-width: 100%;
+		}
+
+		body {
+			-webkit-font-smoothing: antialiased;
+			-webkit-text-size-adjust: none;
+			width: 100% !important;
+			height: 100%;
+			line-height: 1.6em;
+		}
+
+		body {
+			background-color: #f6f6f6;
+		}
+
+		@media only screen and (max-width: 640px) {
+			body {
+				padding: 0 !important;
+			}
+
+			h1 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h2 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h3 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h4 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h1 {
+				font-size: 22px !important;
+			}
+
+			h2 {
+				font-size: 18px !important;
+			}
+
+			h3 {
+				font-size: 16px !important;
+			}
+
+			.container {
+				padding: 0 !important;
+				width: 100% !important;
+			}
+
+			.content {
+				padding: 0 !important;
+			}
+
+			.content-wrap {
+				padding: 10px !important;
+			}
+
+			.invoice {
+				width: 100% !important;
+			}
+		}
+	</style>
+</head>
+
+<body itemscope itemtype="http://schema.org/EmailMessage"
+	  style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; -webkit-font-smoothing: antialiased; -webkit-text-size-adjust: none; width: 100% !important; height: 100%; line-height: 1.6em; background-color: #f6f6f6; margin: 0;"
+	  bgcolor="#f6f6f6">
+
+<table class="main"
+	   style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; box-sizing: border-box; border-radius: 3px; width: 100%; background-color: #f6f6f6; margin: 0px auto;"
+	   cellspacing="0" cellpadding="0" bgcolor="#f6f6f6">
+	<tbody>
+	<tr style="box-sizing: border-box; margin: 0px;">
+		<td class="content-wrap" style="box-sizing: border-box; vertical-align: top; margin: 0px; padding: 20px;"
+			align="center" valign="top">
+			<table style="box-sizing: border-box; border: 1px solid #e9e9e9; border-radius: 3px; margin: 0px; height: 223px; padding: 20px; background-color: #ffffff; width: 600px; max-width: 600px !important;"
+				   width="600" cellspacing="0" cellpadding="0">
+				<tbody>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; color: #348eda; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 84px;"
+						valign="top">
+						<h2>Your ThingsBoard account feature was enabled</h2>
+					</td>
+				</tr>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 40px;"
+						valign="top">We have enabled the ${apiFeature} for your account and ThingsBoard is already able to ${apiLabel} messages.
+					</td>
+				</tr>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 40px;"
+						valign="top">&mdash; The ThingsBoard
+					</td>
+				</tr>
+				</tbody>
+			</table>
+		</td>
+	</tr>
+	</tbody>
+</table>
+<table style="color: #999999; font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; box-sizing: border-box; margin: 0px auto; height: 64px; background-color: #f6f6f6; width: 100%;"
+	   cellpadding="0px 0px 20px">
+	<tbody>
+	<tr style="box-sizing: border-box; margin: 0px;">
+		<td class="aligncenter content-block"
+			style="box-sizing: border-box; font-size: 12px; margin: 0px; padding: 0px 0px 20px; width: 600px; text-align: center; vertical-align: middle;"
+			align="center" valign="top">This email was sent to&nbsp;<a
+					style="box-sizing: border-box; color: #999999; margin: 0px;"
+					href="mailto:${targetEmail}">${targetEmail}</a>&nbsp;by ThingsBoard.
+		</td>
+	</tr>
+	</tbody>
+</table>
+</body>
+</html>

+<#--
+
+    Copyright © 2016-2020 The Thingsboard Authors
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+-->
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+		"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml"
+	  style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+<head>
+	<meta name="viewport" content="width=device-width"/>
+	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+	<title>Thingsboard - Api Usage State</title>
+
+
+	<style type="text/css">
+		img {
+			max-width: 100%;
+		}
+
+		body {
+			-webkit-font-smoothing: antialiased;
+			-webkit-text-size-adjust: none;
+			width: 100% !important;
+			height: 100%;
+			line-height: 1.6em;
+		}
+
+		body {
+			background-color: #f6f6f6;
+		}
+
+		@media only screen and (max-width: 640px) {
+			body {
+				padding: 0 !important;
+			}
+
+			h1 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h2 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h3 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h4 {
+				font-weight: 800 !important;
+				margin: 20px 0 5px !important;
+			}
+
+			h1 {
+				font-size: 22px !important;
+			}
+
+			h2 {
+				font-size: 18px !important;
+			}
+
+			h3 {
+				font-size: 16px !important;
+			}
+
+			.container {
+				padding: 0 !important;
+				width: 100% !important;
+			}
+
+			.content {
+				padding: 0 !important;
+			}
+
+			.content-wrap {
+				padding: 10px !important;
+			}
+
+			.invoice {
+				width: 100% !important;
+			}
+		}
+	</style>
+</head>
+
+<body itemscope itemtype="http://schema.org/EmailMessage"
+	  style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; -webkit-font-smoothing: antialiased; -webkit-text-size-adjust: none; width: 100% !important; height: 100%; line-height: 1.6em; background-color: #f6f6f6; margin: 0;"
+	  bgcolor="#f6f6f6">
+
+<table class="main"
+	   style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; box-sizing: border-box; border-radius: 3px; width: 100%; background-color: #f6f6f6; margin: 0px auto;"
+	   cellspacing="0" cellpadding="0" bgcolor="#f6f6f6">
+	<tbody>
+	<tr style="box-sizing: border-box; margin: 0px;">
+		<td class="content-wrap" style="box-sizing: border-box; vertical-align: top; margin: 0px; padding: 20px;"
+			align="center" valign="top">
+			<table style="box-sizing: border-box; border: 1px solid #e9e9e9; border-radius: 3px; margin: 0px; height: 223px; padding: 20px; background-color: #ffffff; width: 600px; max-width: 600px !important;"
+				   width="600" cellspacing="0" cellpadding="0">
+				<tbody>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; color: #348eda; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 84px;"
+						valign="top">
+						<h2>Your ThingsBoard account feature may be disabled soon</h2>
+					</td>
+				</tr>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 40px;"
+						valign="top">
+						ThingsBoard has already&nbsp;${apiValueLabel}.<br> ${apiFeature} will be disabled for your account once the limit will be reached.
+					</td>
+				</tr>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 59px;"
+						valign="top">Please contact your system administrator to resolve the issue.
+					</td>
+				</tr>
+				<tr style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; box-sizing: border-box; font-size: 14px; margin: 0;">
+					<td class="content-block"
+						style="font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; box-sizing: border-box; font-size: 14px; vertical-align: top; margin: 0px; padding: 0px 0px 20px; height: 40px;"
+						valign="top">&mdash; The ThingsBoard
+					</td>
+				</tr>
+				</tbody>
+			</table>
+		</td>
+	</tr>
+	</tbody>
+</table>
+<table style="color: #999999; font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14px; box-sizing: border-box; margin: 0px auto; height: 64px; background-color: #f6f6f6; width: 100%;"
+	   cellpadding="0px 0px 20px">
+	<tbody>
+	<tr style="box-sizing: border-box; margin: 0px;">
+		<td class="aligncenter content-block"
+			style="box-sizing: border-box; font-size: 12px; margin: 0px; padding: 0px 0px 20px; width: 600px; text-align: center; vertical-align: middle;"
+			align="center" valign="top">This email was sent to&nbsp;<a
+					style="box-sizing: border-box; color: #999999; margin: 0px;"
+					href="mailto:${targetEmail}">${targetEmail}</a>&nbsp;by ThingsBoard.
+		</td>
+	</tr>
+	</tbody>
+</table>
+</body>
+</html>

@@ -18,16 +18,19 @@ package org.thingsboard.server.common.data;
 import lombok.Getter;
 
 public enum ApiFeature {
-    TRANSPORT("transportApiState"),
-    DB("dbApiState"),
-    RE("ruleEngineApiState"),
-    JS("jsExecutionApiState");
+    TRANSPORT("transportApiState", "Device API"),
+    DB("dbApiState", "Telemetry persistence"),
+    RE("ruleEngineApiState", "Rule Engine execution"),
+    JS("jsExecutionApiState", "JavaScript functions execution");
 
     @Getter
     private final String apiStateKey;
+    @Getter
+    private final String label;
 
-    ApiFeature(String apiStateKey) {
+    ApiFeature(String apiStateKey, String label) {
         this.apiStateKey = apiStateKey;
+        this.label = label;
     }
 
 }

+/**
+ * Copyright © 2016-2020 The Thingsboard Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.thingsboard.server.common.data;
+
+import lombok.Data;
+
+@Data
+public class ApiUsageStateMailMessage {
+    private final ApiUsageRecordKey key;
+    private final long threshold;
+    private final long value;
+}

@@ -16,6 +16,9 @@
 package org.thingsboard.rule.engine.api;
 
 import com.fasterxml.jackson.databind.JsonNode;
+import org.thingsboard.server.common.data.ApiFeature;
+import org.thingsboard.server.common.data.ApiUsageStateMailMessage;
+import org.thingsboard.server.common.data.ApiUsageStateValue;
 import org.thingsboard.server.common.data.exception.ThingsboardException;
 
 import javax.mail.MessagingException;
@@ -39,4 +42,6 @@ public interface MailService {
     void send(String from, String to, String cc, String bcc, String subject, String body) throws MessagingException;
 
     void sendAccountLockoutEmail( String lockoutEmail, String email, Integer maxFailedLoginAttempts) throws ThingsboardException;
+
+    void sendApiFeatureStateEmail(ApiFeature apiFeature, ApiUsageStateValue stateValue, String email, ApiUsageStateMailMessage msg) throws ThingsboardException;
 }