add an event information reminder when the network is disconnected.

PluginsAndFeatures/azure-toolkit-for-intellij/src/com/microsoft/intellij/helpers/UIHelperImpl.java

@@ -65,6 +65,7 @@
 import com.microsoft.intellij.helpers.webapp.DeploymentSlotPropertyViewProvider;
 import com.microsoft.intellij.helpers.webapp.WebAppPropertyViewProvider;
 import com.microsoft.intellij.ui.util.UIUtils;
+import com.microsoft.intellij.util.PluginUtil;
 import com.microsoft.tooling.msservices.components.DefaultLoader;
 import com.microsoft.tooling.msservices.helpers.UIHelper;
 import com.microsoft.tooling.msservices.model.storage.Queue;
@@ -758,6 +759,11 @@ public String showInputDialog(Component component, String message, String title,
         return runFromDispatchThread(() -> Messages.showInputDialog(component, message, title, icon));
     }
 
+    @Override
+    public void showInfoNotification(String title, String message) {
+        PluginUtil.showInfoNotification(title, message);
+    }
+
     private static <T> T runFromDispatchThread(Supplier<T> supplier) {
         if (ApplicationManager.getApplication().isDispatchThread()) {
             return supplier.get();

PluginsAndFeatures/azure-toolkit-for-intellij/src/com/microsoft/intellij/util/PluginUtil.java

@@ -202,6 +202,12 @@ public static void showErrorNotificationProject(Project project, String title, S
                          message, NotificationType.ERROR).notify(project);
     }
 
+    public static void showInfoNotification(String title, String message) {
+        Notification notification = new Notification(NOTIFICATION_GROUP_ID, title,
+                message, NotificationType.INFORMATION);
+        Notifications.Bus.notify(notification);
+    }
+
     public static void showWarnNotification(String title, String message) {
         Notification notification = new Notification(NOTIFICATION_GROUP_ID, title,
                 message, NotificationType.WARNING);

Utils/azure-explorer-common/src/com/microsoft/tooling/msservices/helpers/UIHelper.java

@@ -154,4 +154,8 @@ default boolean showYesNoDialog(Component component, String message, String titl
     default String showInputDialog(Component component, String message, String title, Icon icon) {
         return (String) JOptionPane.showInputDialog(component, message, title, JOptionPane.QUESTION_MESSAGE, icon, null, null);
     }
+
+    default void showInfoNotification(String title, String message) {
+
+    }
 }

Utils/azure-explorer-common/src/com/microsoft/tooling/msservices/serviceexplorer/azure/AzureModule.java

@@ -26,6 +26,8 @@
 import com.microsoft.azuretools.authmanage.AuthMethodManager;
 import com.microsoft.azuretools.authmanage.SubscriptionManager;
 import com.microsoft.azuretools.authmanage.models.SubscriptionDetail;
+import com.microsoft.azuretools.enums.ErrorEnum;
+import com.microsoft.azuretools.exception.AzureRuntimeException;
 import com.microsoft.azuretools.azurecommons.helpers.AzureCmdException;
 import com.microsoft.azuretools.azurecommons.helpers.NotNull;
 import com.microsoft.azuretools.azurecommons.helpers.Nullable;
@@ -121,6 +123,9 @@ private static String composeName() {
                     .filter(SubscriptionDetail::isSelected).collect(Collectors.toList());
             return String.format("%s (%s)", BASE_MODULE_NAME, getAccountDescription(selectedSubscriptions));
 
+        } catch (AzureRuntimeException e) {
+            DefaultLoader.getUIHelper().showInfoNotification(
+                    ERROR_GETTING_SUBSCRIPTIONS_TITLE, ErrorEnum.getDisplayMessageByCode(e.getCode()));
         } catch (Exception e) {
             final String msg = String.format(ERROR_GETTING_SUBSCRIPTIONS_MESSAGE, e.getMessage());
             DefaultLoader.getUIHelper().showException(msg, e, ERROR_GETTING_SUBSCRIPTIONS_TITLE, false, true);

Utils/azuretools-core/src/com/microsoft/azuretools/enums/ErrorEnum.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) Microsoft Corporation
+ *
+ * All rights reserved.
+ *
+ * MIT License
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and
+ * to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of
+ * the Software.
+ *
+ * THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
+ * THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.microsoft.azuretools.enums;
+
+/**
+ * Enums of backend errors for azure tools.
+ */
+public enum ErrorEnum {
+    UNKNOWN_HOST_EXCEPTION(100000, "Encountered an unknown host exception.",
+            "It seems you have an unstable network at the moment, please try again when network is available."),
+    SOCKET_TIMEOUT_EXCEPTION(100002, "Encountered a socket timeout exception.",
+            "Timeout when accessing azure, please try your operation again."),
+    FAILED_TO_GET_ACCESS_TOKEN_BY_CLI(100003, "Failed to get access token by Azure CLI command.",
+            "Failed to get access token, please try to login Azure CLI using 'az login' and try again."),
+    ;
+
+    private int errorCode;
+    private String errorMessage;
+    private String displyMessage;
+
+    ErrorEnum(int errorCode, String errorMessage, String displayMessage) {
+        this.errorCode = errorCode;
+        this.errorMessage = errorMessage;
+        this.displyMessage = displayMessage;
+    }
+
+    public int getErrorCode() {
+        return errorCode;
+    }
+
+    public String getErrorMessage() {
+        return errorMessage;
+    }
+
+    public String getDisplyMessage() {
+        return displyMessage;
+    }
+
+    public static String getDisplayMessageByCode(int code) {
+        for (ErrorEnum e : ErrorEnum.values()) {
+            if (e.getErrorCode() == code) {
+                return e.getDisplyMessage();
+            }
+        }
+        throw new IllegalArgumentException(String.format("Not found enum for code: %s", code));
+    }
+
+}

Utils/azuretools-core/src/com/microsoft/azuretools/exception/AzureRuntimeException.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) Microsoft Corporation
+ *
+ * All rights reserved.
+ *
+ * MIT License
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and
+ * to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of
+ * the Software.
+ *
+ * THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
+ * THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.microsoft.azuretools.exception;
+
+import com.microsoft.azuretools.enums.ErrorEnum;
+
+/**
+ * RuntinmeException for azure tools.
+ */
+public class AzureRuntimeException extends RuntimeException {
+
+    private int code;
+
+    public AzureRuntimeException(ErrorEnum errorEnum) {
+        super(errorEnum.getErrorMessage());
+        this.code = errorEnum.getErrorCode();
+    }
+
+    public AzureRuntimeException(int code) {
+        this.code = code;
+    }
+
+    public AzureRuntimeException(int code, String message) {
+        super(message);
+        this.code = code;
+    }
+
+    public AzureRuntimeException(int code, String message, Throwable cause) {
+        super(message, cause);
+        this.code = code;
+    }
+
+    public int getCode() {
+        return code;
+    }
+}

Utils/azuretools-core/src/com/microsoft/azuretools/sdkmanage/AzureCliAzureManager.java

@@ -34,7 +34,9 @@
 import com.microsoft.azuretools.authmanage.CommonSettings;
 import com.microsoft.azuretools.authmanage.Environment;
 import com.microsoft.azuretools.authmanage.models.AuthMethodDetails;
+import com.microsoft.azuretools.exception.AzureRuntimeException;
 import com.microsoft.azuretools.azurecommons.helpers.Nullable;
+import com.microsoft.azuretools.enums.ErrorEnum;
 import com.microsoft.azuretools.utils.CommandUtils;
 import com.microsoft.azuretools.utils.Pair;
 import org.apache.commons.lang.ObjectUtils;
@@ -188,6 +190,9 @@ private Pair<String, OffsetDateTime> getAccessTokenViaCli(String tid, @Nullable
                                String.format(CLI_TOKEN_FORMAT_ACCESSOR, tid) :
                                String.format(CLI_TOKEN_FORMAT_ACCESSOR_RESOURCE, tid, resource);
         final String jsonToken = CommandUtils.exec(command);
+        if (StringUtils.isBlank(jsonToken)) {
+            throw new AzureRuntimeException(ErrorEnum.FAILED_TO_GET_ACCESS_TOKEN_BY_CLI);
+        }
         final Map<String, Object> objectMap = JsonUtils.fromJson(jsonToken, Map.class);
         final String strToken = (String) objectMap.get(CLI_TOKEN_PROP_ACCESS_TOKEN);
         final String strTime = (String) objectMap.get(CLI_TOKEN_PROP_EXPIRATION);

Utils/azuretools-core/src/com/microsoft/azuretools/sdkmanage/AzureManagerBase.java

@@ -22,6 +22,7 @@
 
 package com.microsoft.azuretools.sdkmanage;
 
+import com.google.common.base.Throwables;
 import com.microsoft.azure.AzureEnvironment;
 import com.microsoft.azure.arm.resources.AzureConfigurable;
 import com.microsoft.azure.credentials.AzureTokenCredentials;
@@ -30,18 +31,17 @@
 import com.microsoft.azure.management.appplatform.v2019_05_01_preview.implementation.AppPlatformManager;
 import com.microsoft.azure.management.resources.Subscription;
 import com.microsoft.azure.management.resources.Tenant;
-import com.microsoft.azuretools.authmanage.CommonSettings;
-import com.microsoft.azuretools.authmanage.Environment;
-import com.microsoft.azuretools.authmanage.RefreshableTokenCredentials;
-import com.microsoft.azuretools.authmanage.SubscriptionManager;
-import com.microsoft.azuretools.authmanage.SubscriptionManagerPersist;
+import com.microsoft.azuretools.authmanage.*;
+import com.microsoft.azuretools.exception.AzureRuntimeException;
+import com.microsoft.azuretools.enums.ErrorEnum;
 import com.microsoft.azuretools.telemetry.TelemetryInterceptor;
 import com.microsoft.azuretools.utils.AzureRegisterProviderNamespaces;
 import com.microsoft.azuretools.utils.Pair;
 import org.apache.commons.lang3.StringUtils;
 import rx.Observable;
 
 import java.io.IOException;
+import java.net.UnknownHostException;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
@@ -51,10 +51,7 @@
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 
-import static com.microsoft.azuretools.authmanage.Environment.CHINA;
-import static com.microsoft.azuretools.authmanage.Environment.GERMAN;
-import static com.microsoft.azuretools.authmanage.Environment.GLOBAL;
-import static com.microsoft.azuretools.authmanage.Environment.US_GOVERNMENT;
+import static com.microsoft.azuretools.authmanage.Environment.*;
 
 /**
  * Created by vlashch on 1/27/17.
@@ -249,14 +246,20 @@ private List<Subscription> getSubscriptions(Azure.Authenticated tenantAuthentica
     }
 
     private List<Tenant> getTenants(Azure.Authenticated authentication) {
-        return authentication.tenants().listAsync()
-                .onErrorResumeNext(err -> {
-                    LOGGER.warning(err.getMessage());
-                    return Observable.empty();
-                })
-                .toList()
-                .toBlocking()
-                .singleOrDefault(Collections.emptyList());
+        try {
+            return authentication.tenants().listAsync()
+                    .toList()
+                    .toBlocking()
+                    .singleOrDefault(Collections.emptyList());
+        } catch (Exception err) {
+            LOGGER.warning(Throwables.getStackTraceAsString(err));
+            if (Throwables.getCausalChain(err).stream().filter(e -> e instanceof UnknownHostException).count() > 0) {
+                throw new AzureRuntimeException(ErrorEnum.UNKNOWN_HOST_EXCEPTION);
+            } else if (err instanceof AzureRuntimeException) {
+                throw err;
+            }
+            return Collections.emptyList();
+        }
     }
 
     protected Azure.Authenticated authTenant(String tenantId) {