### Getting Started with Dew DevOps Example Project

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/quick-start.adoc

This snippet provides the commands to clone, install, and deploy the example To-Do project using Dew DevOps. It also includes instructions for local host mapping and accessing the deployed application. Prerequisites include Java (>=11), Maven, and NodeJS (>=8).

```Shell
# ======= 前置准备 =======
# 执行dew-devops.sh根据提示创建项目
sh dew-devops.sh
# 添加本地Host映射
-
x.x.x.x todo-uat.idealworld.group
x.x.x.x todo-api-uat.idealworld.group
-
# ======= 前置准备 =======
git clone https://github.com/dew-ms/devops-example-todo.git
cd devops-example-todo
# 执行安装
mvn install -Dmaven.test.skip=true
# 部署到Kubernetes
mvn -P devops deploy -Ddew_devops_profile=uat
```

--------------------------------

### Install Git

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Installs Git using yum, a prerequisite for some Kubernetes operations.

```bash
yum install -y git
```

--------------------------------

### Install and Configure NFS Server on Linux

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/appendix/middleware.adoc

This snippet provides commands to install NFS utilities, create necessary directories, configure NFS exports in `/etc/exports` for read-write access, and enable/start NFS services. It also includes a command to verify the setup and notes a common Kubernetes mounting error related to missing `nfs-utils`.

```bash
yum install -y nfs-utils
mkdir -p /data/nfs
chmod 755 /data/nfs

# Edit /etc/exports and add the following line:
# /data/nfs     *(rw,sync,no_root_squash,no_all_squash)

systemctl enable rpcbind
systemctl enable nfs-server
systemctl start rpcbind
systemctl start nfs-server

showmount -e localhost
```

--------------------------------

### Install Kubectl for K3s

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Installs the standard `kubectl` command-line tool using an Aliyun mirror and configures it to interact with the K3s cluster.

```bash
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
        http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
yum install -y kubectl
cp /etc/rancher/k3s/k3s.yaml   ~/.kube/config
```

--------------------------------

### Install Harbor Container Registry using Helm

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Steps to add the Harbor Helm repository, update it, and install Harbor with Ingress configuration and node selectors. Includes commands for uninstallation, Docker daemon configuration for insecure registries, and basic Docker commands for logging in and pushing images to Harbor.

```bash
helm repo add harbor https://helm.goharbor.io
helm repo update
helm install dew-harbor harbor/harbor --namespace devops \
    --set expose.type=ingress \
    --set expose.ingress.hosts.core=harbor.dew.idealworld.group \
    --set expose.ingress.hosts.notary=notary.dew.idealworld.group \
    --set externalURL=https://harbor.dew.idealworld.group \
    --set core.nodeSelector.group=devops \
    --set portal.nodeSelector.group=devops \
    --set jobservice.nodeSelector.group=devops \
    --set registry.nodeSelector.group=devops \
    --set chartmuseum.nodeSelector.group=devops \
    --set clair.nodeSelector.group=devops \
    --set notary.nodeSelector.group=devops \
    --set database.internal.nodeSelector.group=devops \
    --set redis.internal.nodeSelector.group=devops

# 删除 helm uninstall dew-harbor --namespace devops

# 添加 ``"insecure-registries": ["harbor.dew.idealworld.group"]`` 到 /etc/docker/daemon.json
# 登录Harbor docker login <host> -u <user> -p <password>
docker login harbor.dew.idealworld.group -u admin -p Harbor12345<请修改>
# e.g. 上传镜像
docker pull dewms/devops:latest
docker tag dewms/devops:latest harbor.dew.idealworld.group/dewms/devops:latest
docker push harbor.dew.idealworld.group/dewms/devops:latest
```

--------------------------------

### Verify Metrics Server Installation

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Verifies the successful installation of Metrics Server by checking node and pod resource usage.

```bash
kubectl top node
kubeadm top pod
```

--------------------------------

### Install GitLab CE using Omnibus Package

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Instructions for installing GitLab Community Edition on RPM-based systems using the Omnibus package, including repository setup, package installation, configuration file modification for external URL, and reconfigure command. Users are advised to modify the root password via browser after installation.

```bash
curl https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.rpm.sh | sudo bash
yum install -y gitlab-ce

# 按需修改，可修改说明见: https://docs.gitlab.com/omnibus/settings/
vi /etc/gitlab/gitlab.rb
-
external_url 'http://gitlab.dew.idealworld.group'
...
-
gitlab-ctl reconfigure

# 浏览器访问并修改root密码
```

--------------------------------

### Install Helm 3

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Installs Helm 3, the Kubernetes package manager, using the official installation script.

```bash
curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 | bash
```

--------------------------------

### Basic Authentication Cache Usage Example in Java

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

This Java example illustrates a complete flow of user authentication using Dew's authentication cache. It includes mock implementations for user registration, login (setting OptInfoExt), business operations requiring authenticated user data, and logout (removing OptInfo). It demonstrates how to extend OptInfo and interact with Dew.auth.

```Java
/**
 * 模拟用户注册.
 */
@PostMapping(value = "user/register")
public Resp<Void> register(@RequestBody User user) {
    // 实际注册处理
    user.setId($.field.createUUID());
    MOCK_USER_CONTAINER.put(user.getId(), user);
    return Resp.success(null);
}

/**
 * 模拟用户登录.
 */
@PostMapping(value = "auth/login")
public Resp<String> login(@RequestBody LoginDTO loginDTO) {
    // 实际登录处理
    User user = MOCK_USER_CONTAINER.values().stream().filter(u -> u.getIdCard().equals(loginDTO.getIdCard())).findFirst().get();
    String token = $.field.createUUID();
    Dew.auth.setOptInfo(new OptInfoExt()
            .setIdCard(user.getIdCard())
            .setAccountCode($.field.createShortUUID())
            .setToken(token)
            .setName(user.getName())
            .setMobile(user.getPhone())
            .setRoleInfo(new HashSet<>() {
                {
                    add(new OptInfo.RoleInfo()
                            .setCode(userDTO.getRole())
                            .setName(".."
                    );
                }
            }));
    return Resp.success(token);
}

/**
 * 模拟业务操作.
 */
@GetMapping(value = "business/someopt")
public Resp<Void> someOpt() {
    // 获取登录用户信息
    Optional<OptInfoExt> optInfoExtOpt = Dew.auth.getOptInfo();
    if (!optInfoExtOpt.isPresent()) {
        return Resp.unAuthorized("用户认证错误");
    }
    // 登录用户的信息
    optInfoExtOpt.get();
    return Resp.success(null);
}

/**
 * 模拟用户注销.
 */
@DeleteMapping(value = "auth/logout")
public Resp<Void> logout() {
    // 实际注册处理
    Dew.auth.removeOptInfo();
    return Resp.success(null);
}
```

--------------------------------

### Deploy Sonatype Nexus using Helm

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Steps to add the Oteemo Helm repository and install Sonatype Nexus with Ingress enabled and custom host configurations for HTTP and Docker proxies. Default administrator credentials are provided.

```bash
helm repo add oteemocharts https://oteemo.github.io/charts
helm repo update
helm install dew-nexus oteemocharts/sonatype-nexus --namespace devops \
    --set ingress.enabled=true \
    --set nexusProxy.env.nexusHttpHost=maven.dew.idealworld.group \
    --set nexusProxy.env.nexusDockerHost=maven.dew.idealworld.group

# 用户名 admin 密码 admin123
```

--------------------------------

### Install K3s Server

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Installs the K3s server, configuring it to use Docker and disabling Traefik for custom ingress solutions.

```bash
curl -sfL https://docs.rancher.cn/k3s/k3s-install.sh | INSTALL_K3S_MIRROR=cn INSTALL_K3S_EXEC="server --docker --no-deploy traefik" sh -
```

--------------------------------

### Install Calico Network Plugin

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Applies the Calico CNI manifest to install the network plugin for pod communication.

```bash
kubectl apply -f https://docs.projectcalico.org/v3.14/manifests/calico.yaml
```

--------------------------------

### Dew Recommended Java Code Package Structure and MQ Listener Example

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

Details the recommended package structure for a Dew service, including key classes like XApplication (service startup), XConfig (Spring Cloud configuration), XInitiator (initialization for DB/cache/tasks), and controller packages for interaction interfaces like MQ receivers. An example of an MQ listener using Dew's cluster MQ feature is provided.

```APIDOC
|- X service
|-  |- src
|-  |-  |- main
|-  |-  |-  |- java
|-  |-  |-  |-  |- src
|-  |-  |-  |-  |-  |- x.y.z
|-  |-  |-  |-  |-  |-  |- XApplication (1)
|-  |-  |-  |-  |-  |-  |- XConfig (2)
|-  |-  |-  |-  |-  |-  |- XInitiator (3)
|-  |-  |-  |-  |-  |-  |- controller
|-  |-  |-  |-  |-  |-  |-  |- EventController (4)

(1) XApplication: 服务启动类 (Service startup class)
(2) XConfig: 当前服务的配置文件（Spring Cloud格式） (Current service configuration file (Spring Cloud format))
(3) XInitiator: 当前服务启动初始化器，原则上所有与数据库、缓存、定时任务相关的初始化操作都应该从此类发起，以方便排错 (Current service startup initializer; all database, cache, and scheduled task initializations should originate here for easier troubleshooting)
(4) EventController: 事件处理器，名称可以更具象，原则上所有与MQ receive相关的操作都被视为交互接口，应该放到controller包下 (Event handler; name can be more specific; all MQ receive-related operations are considered interaction interfaces and should be placed under the controller package)
```

```Java
@PostConstruct
public void processTodoAddEvent() {
    // 使用Dew的集群MQ功能实现消息点对点接收
    Dew.cluster.mq.response(Constants.MQ_NOTIFY_TODO_ADD, todo -> {
        logger.info("Received add todo event :" + todo);
    });
}
```

--------------------------------

### Java Example for MQ Publish-Subscribe and Request-Response

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

This Java example demonstrates the usage of Dew's ClusterMQ service. It shows how to subscribe to a topic for publish-subscribe messaging, publish messages with and without custom headers, and how to set up a responder and send requests for request-response communication. It highlights the non-blocking nature of subscribe and response methods. Note that topics must exist before publishing; subscribing to a topic will automatically create it.

```Java
// pub-sub
Dew.cluster.mq.subscribe("test_pub_sub", message ->
        logger.info("pub_sub>>" + message.getBody()));
Dew.cluster.mq.publish("test_pub_sub", "msgA",new HashMap<String, Object>() {
      {
          put("h", "001");
      }
  });
Dew.cluster.mq.publish("test_pub_sub", "msgB");
// req-resp
Dew.cluster.mq.response("test_rep_resp", message ->
        logger.info("req_resp>>" + message.getBody()));
Dew.cluster.mq.request("test_rep_resp", "msg1",new HashMap<String, Object>() {
      {
          put("h", "001");
      }
  });
Dew.cluster.mq.request("test_rep_resp", "msg2");
```

--------------------------------

### Install Metrics Server for Kubernetes

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Installs the Metrics Server, required for Horizontal Pod Autoscaling (HPA), by applying the official components YAML.

```bash
kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml
```

--------------------------------

### Kubernetes Ingress Configuration Created by Dew DevOps

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/quick-start.adoc

This snippet shows an example Kubernetes Ingress configuration generated by `dew-devops.sh`. It defines host-based routing for different services (kernel and frontend) within a Kubernetes namespace, mapping domains to service names and ports.

```Kubernetes YAML
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
  name: dew-ingress
  namespace: dew-uat
spec:
  rules:
  - host: api-uat.idealworld.group
    http:
      paths:
      - backend:
          serviceName: kernel
          servicePort: 8080
        path: /
  - host: uat.dew.idealworld.group
    http:
      paths:
      - backend:
          serviceName: frontend
          servicePort: 80
        path: /
```

--------------------------------

### Install Nginx Ingress Controller using Helm

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Instructions for installing the Nginx Ingress Controller via Helm, exposing ports 80 and 443, and enabling metrics. It configures the controller as a DaemonSet with host network enabled. Includes a command for uninstallation.

```bash
# 使用如下方式将80 443暴露出来
helm install dew-nginx stable/nginx-ingress --namespace nginx-ingress \
    --set controller.kind=DaemonSet \
    --set controller.hostNetwork=true \
    --set defaultBackend.enabled=false \
    --set controller.metrics.enabled=true

# 删除 helm uninstall dew-nginx --namespace nginx-ingress
```

--------------------------------

### Install K3s Agent

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Installs a K3s agent node, configuring it to use Docker and disabling Traefik and ServiceLB, then joining it to the K3s server using the provided URL and token.

```bash
curl -sfL https://docs.rancher.cn/k3s/k3s-install.sh | \
  INSTALL_K3S_MIRROR=cn INSTALL_K3S_EXEC="--docker --no-deploy traefik --no-deploy servicelb" \
  K3S_URL=https://<SERVER IP>:6443 K3S_TOKEN=<TOKEN> sh -
```

--------------------------------

### Install Kibana with NFS Persistent Volume

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Instructions for deploying Kibana using Helm, including creating an NFS directory, and defining Kubernetes Persistent Volume (PV) and Persistent Volume Claim (PVC) for storage. Also provides notes on using StorageClass instead of explicit PV/PVC creation.

```bash
# 使用NFS存储，创建PV & PVC

# 在NFS节点中创建NFS目录
mkdir -p /data/nfs/kibana

# 在Kubernetes Master节点中创建PV & PVC
cat <<EOF | kubectl -n devops apply -f -
apiVersion: v1
kind: PersistentVolume
metadata:
  labels:
    app: kibana
  name: dew-kibana
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Recycle
  nfs:
    path: /data/nfs/kibana
    server: nfs.dew.idealworld.group
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  labels:
    app: kibana
  name: kibana
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  selector:
    matchLabels:
      app: kibana
EOF

# 若使用 StorageClass，则无需创建PV，PVC，需设置以下参数
# 将existingClaim的值改为false    --set persistentVolumeClaim.existingClaim=false
# 设置StorageClass的名字    --set persistentVolumeClaim.storageClass="yourscname"
```

--------------------------------

### Dew Authentication Cache Usage Example

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

This Java example demonstrates a full authentication flow, including user registration, login, a sample business operation requiring authentication, and logout. It illustrates how to use `Dew.auth.setOptInfo`, `Dew.auth.getOptInfo`, and `Dew.auth.removeOptInfo` within a Spring Boot-like controller to manage user session data, including extending `OptInfo` with custom properties.

```Java
/**
 * 模拟用户注册.
 */
@PostMapping(value = "user/register")
public Resp<Void> register(@RequestBody User user) {
    // 实际注册处理
    user.setId($.field.createUUID());
    MOCK_USER_CONTAINER.put(user.getId(), user);
    return Resp.success(null);
}
    
/**
 * 模拟用户登录.
 */
@PostMapping(value = "auth/login")
public Resp<String> login(@RequestBody LoginDTO loginDTO) {
    // 实际登录处理
    User user = MOCK_USER_CONTAINER.values().stream().filter(u -> u.getIdCard().equals(loginDTO.getIdCard())).findFirst().get();
    String token = $.field.createUUID();
    Dew.auth.setOptInfo(new OptInfoExt()
            .setIdCard(user.getIdCard())
            .setAccountCode($.field.createShortUUID())
            .setToken(token)
            .setName(user.getName())
            .setMobile(user.getPhone())
            .setRoleInfo(new HashSet<>() {
                {
                    add(new OptInfo.RoleInfo()
                            .setCode(userDTO.getRole())
                            .setName("..")
                    );
                }
            }));
    return Resp.success(token);
}
    
/**
 * 模拟业务操作.
 */
@GetMapping(value = "business/someopt")
public Resp<Void> someOpt() {
    // 获取登录用户信息
    Optional<OptInfoExt> optInfoExtOpt = Dew.auth.getOptInfo();
    if (!optInfoExtOpt.isPresent()) {
        return Resp.unAuthorized("用户认证错误");
    }
    // 登录用户的信息
    optInfoExtOpt.get();
    return Resp.success(null);
}
    
/**
 * 模拟用户注销.
 */
@DeleteMapping(value = "auth/logout")
public Resp<Void> logout() {

```

--------------------------------

### Check Helm Version

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Command to display the installed Helm client and server versions.

```bash
helm version
```

--------------------------------

### Dew Configuration File Reference

Source: https://github.com/gudaoxuri/dew/blob/master/devops/it/src/it/helloworld-frontend/readme.adoc

This snippet indicates how the project's .dew configuration file is referenced. This file typically contains YAML definitions crucial for DevOps settings within the Dew microservice system, enabling automated deployments.

```yml
include::.dew[]
```

--------------------------------

### Using HBaseTemplate in Spring Boot

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

Illustrates how to inject and use `HBaseTemplate` in a Spring Boot application to perform operations like retrieving data from HBase. The example shows a `get` operation with a custom row mapper.

```Java
@Autowired
private HBaseTemplate hbaseTemplate;

hbaseTemplate.get("table_hbase", "0002093140000000",
                "0", "reg_platform", (result, row) -> Bytes.toString(result.value()));
```

--------------------------------

### Helm Installation Notes and Configuration for Prometheus Operator

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

This section provides essential notes and configuration parameters for installing the Prometheus Operator using Helm. It covers creating necessary secrets for etcd monitoring, adjusting image repositories, enabling etcd monitoring, configuring Grafana via `grafana.ini`, and using StorageClasses for persistent storage for Grafana, Prometheus, and Alertmanager.

```text
# 若需要对etcd进行监控，则需要先创建secret
kubectl -n devops create secret generic dew-prometheus-operator-etcd \
  --from-file=/etc/kubernetes/pki/etcd/ca.crt \
  --from-file=/etc/kubernetes/pki/etcd/peer.crt \
  --from-file=/etc/kubernetes/pki/etcd/peer.key

# 安装
# · 不使用代理要加上 --set kube-state-metrics.image.repository=registry.cn-hangzhou.aliyuncs.com/google_containers/kube-state-metrics
# · 若要启用对etcd监控，需设置kubeEtcd相关参数。
# · grafana.'grafana\.ini'为Grafana的配置参数,请安装时自行修改。
# · 使用StorageClass
#    - 若 Grafana 使用StorageClass，需要进行以下配置，无需创建PV，PVC
#      --set grafana.persistence.storageClassName="yourscname"
#      --set grafana.persistence.size=10Gi
#      删去此行配置：    --set grafana.persistence.existingClaim=grafana \
#    - Prometheus使用StorageClass,需要添加以下配置，无需创建PV，PVC
#      --set prometheus.prometheusSpec.storageSpec.volumeClaimTemplate.spec.storageClassName="yourscname" \
#    - Alertmanager和Prometheus使用StorageClass,需要添加以下配置，无需创建PVC，但因为自动生成的PVC名称过长，
#      而无法动态创建PV，所以需要自行修改chart相关配置或指定已创建好的PV名称：
#      --set alertmanager.alertmanagerSpec.storage.volumeClaimTemplate.spec.volumeName=prometheus-alertmanager \
```

--------------------------------

### Add Helm Charts Repository

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Removes the default stable repository and adds the Azure China mirror for Helm charts, then updates the repository index.

```bash
helm repo remove stable
helm repo add stable http://mirror.azure.cn/kubernetes/charts/
helm repo update
```

--------------------------------

### Verify All Pods Status

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Checks the status of all pods across all namespaces to confirm successful deployment.

```bash
kubectl get pods --all-namespaces
```

--------------------------------

### Java Example: Using ClusterLock for Distributed Locking

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

Demonstrates how to create a `ClusterLock` instance, acquire a lock using `tryLock` with manual unlocking, and a simplified approach using `tryLockWithFun` which handles automatic unlocking.

```Java
// 创建指定名为test_lock的分布锁实例
ClusterLock lock = Dew.cluster.lock.instance("test_lock");
// tryLock 示例，等待0ms，忘了手工unLock或出异常时1s后自动解锁
if (lock.tryLock(0, 1000)) {
    try {
        // 已加锁，执行业务方法
    } finally {
        // 手工解锁
        lock.unLock();
    }
}
// 上面的示例可用 tryLockWithFun 简化
lock.tryLockWithFun(0, 1000, () -> {
    // 已加锁，执行业务方法，tryLockWithFun会将业务方法包裹在try-finally中，无需手工解锁
});
```

--------------------------------

### Java Example for Dew Cluster Distributed Cache Operations

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

This Java code snippet demonstrates common operations using Dew Cluster's distributed cache. It includes examples for flushing the database, deleting keys, checking key existence, setting values with expiration, and retrieving values, showcasing basic interactions with the `Dew.cluster.cache` API.

```Java
// 清空DB
Dew.cluster.cache.flushdb();
// 删除key
Dew.cluster.cache.del("n_test");
// 判断是否存在
Dew.cluster.cache.exists("n_test");
// 设置值
Dew.cluster.cache.set("n_test", "{\"name\":\"jzy\"}", 1);
// 获取值并转成Json
$.json.toJson(Dew.cluster.cache.get("n_test"));
```

--------------------------------

### Join Node to Kubernetes Cluster and Verify

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Instructions for joining a worker node to the Kubernetes cluster using the `kubeadm join` command, followed by verifying node status on the master.

```bash
# 执行上一步输出的 kubeadm join ...

# 完成后在master上执行情况如下（以1.18版本为例）
kubeadm get no
```

--------------------------------

### GitLab High Availability Configuration Reference

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Reference to the official GitLab documentation for setting up High Availability (HA) configurations.

```APIDOC
# @see https://about.gitlab.com/solutions/high-availability/
```

--------------------------------

### Example Dew Custom Exception Mapping Configuration (XML)

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

Provides an example of configuring `java.io.IOException` to return a 200 HTTP status code and a custom business code 'NBE00123' using Dew's error mapping.

```xml
dew:
  basic:
    error-mapping:
      "java.io.IOException":
        http-code: 200
        business-code: "NBE00123"
```

--------------------------------

### Dew Notification Configuration Example

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

Provides concrete examples of configuring different notification types: a DingTalk notification for errors, an email notification, and a custom HTTP notification.

```YAML
# 示例
dew:
  notifies:
    __DEW_ERROR__:
      type: DD
      defaultReceivers: xxxx
      args:
        url: https://oapi.dingtalk.com/robot/send?access_token=8ff65c48001c1981df7d3269
      strategy:
        minIntervalSec: 5
    sendMail:
      type: MAIL
      defaultReceivers: x@y.z
    custom:
      type: HTTP
      defaultReceivers: x@y.z
      args:
        url: https://...
```

--------------------------------

### Dew Exception Mapping Configuration Example

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

Provides an example of configuring `java.io.IOException` to return a specific HTTP status code (200) and a business code ('NBE00123') when encountered.

```YAML
dew:
  basic:
    error-mapping:
      "java.io.IOException":
        http-code: 200
        business-code: "NBE00123"
```

--------------------------------

### Example of Dew Unified Exception Handling in Java

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

Illustrates how to use `Dew.E.e` to encapsulate and throw an exception in business logic. It also shows the resulting JSON response received by the client, including a custom business code and message.

```java
// 业务代码捕获了一个异常
Exception someError = new IOException("xxx不存在")
// 使用统一异常处理封装
throw Dew.E.e("NBE00123",someError,200)
// 请求方得到的结果为 http状态=200，响应体：
{
    "code": "NBE00123",
    "message": "xxx不存在",
    "body": null
}
```

--------------------------------

### Dew Cache Multi-instance Access Examples

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

Illustrates how to access specific Redis cache instances configured with the `multi` property using `Dew.cluster.caches.instance("<key>")` and also shows usage of the default cache connection.

```Java
// Use the connection with key 'auth'
Dew.cluster.caches.instance("auth").set("token", "xxxxx");
// Use the default connection
Dew.cluster.cache.set("name", "xxxxx")
```

--------------------------------

### Initialize Kubernetes Master with Proxy Network

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Initializes the Kubernetes master node with a specified pod network CIDR, using a proxy method.

```bash
kubeadm init \
    --pod-network-cidr=10.244.0.0/16
```

--------------------------------

### Configure Metrics Server for Kubernetes (Fixes)

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Clones the metrics-server repository, applies 1.8+ deployment files, and patches the deployment to fix TLS and address type issues, and optionally changes the image for non-proxy environments.

```bash
git clone https://github.com/kubernetes-incubator/metrics-server.git
# Kuberneters V1.8以上执行
kubeadm create -f metrics-server/deploy/1.8+/
# Fix issue: https://github.com/kubernetes-incubator/metrics-server/issues/131
kubeadm patch deploy metrics-server -n kube-system -p "
spec:
  template:
    spec:
      containers:
      - name: metrics-server
        command:
        - /metrics-server
        - --kubelet-insecure-tls
        - --kubelet-preferred-address-types=InternalIP"
# 不使用代理，需要修改镜像
kubeadm -n kube-system set image deploy metrics-server metrics-server=rancher/metrics-server-amd64:v0.3.1
```

--------------------------------

### Configure Kubeconfig for Cluster Access

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Sets up the kubeconfig file for accessing the Kubernetes cluster, copying the admin configuration and setting appropriate permissions.

```bash
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

export KUBECONFIG=/etc/kubernetes/admin.conf
```

--------------------------------

### GitLab CI/CD Trigger Condition

Source: https://github.com/gudaoxuri/dew/blob/master/devops/it/src/it/helloworld-frontend/readme.adoc

This snippet describes the trigger condition for automated deployments via GitLab CI/CD. The pipeline will execute when code is merged or pushed to the 'test' branch.

```shell
# Merge或Push代码到test分支
```

--------------------------------

### Basic Dew Cache Usage Examples

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

Demonstrates common operations using the Dew cache, including clearing the database, deleting a key, checking key existence, setting a string value with expiration, and retrieving a value, converting it to JSON.

```Java
// Clear DB
Dew.cluster.cache.flushdb();
// Delete key
Dew.cluster.cache.del("n_test");
// Check existence
Dew.cluster.cache.exists("n_test");
// Set value
Dew.cluster.cache.set("n_test", "{\"name\":\"jzy\"}", 1);
// Get value and convert to Json
$.json.toJson(Dew.cluster.cache.get("n_test"));
```

--------------------------------

### Manual DevOps Deployment Execution

Source: https://github.com/gudaoxuri/dew/blob/master/devops/it/src/it/helloworld-frontend/readme.adoc

This section provides commands for manually preparing the environment and deploying the application to the test environment using Maven. It includes setting necessary environment variables for Kubernetes, Docker host, and Docker registry credentials, followed by the Maven deploy command.

```shell
# 参数设置 (win/unix)
SET/export dew_devops_kube_config=...
SET/export dew_devops_docker_host=...
SET/export dew_devops_docker_registry_url=...
SET/export dew_devops_docker_registry_username=...
SET/export dew_devops_docker_registry_password=...

# 执行如下maven命令(发布到test环境)
mvn -P devops deploy -Ddew_devops_profile=test
```

--------------------------------

### TodoKernelApplication Main Entry Point for Kernel Service

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

This Java class is the main entry point for the kernel service, extending `TodoParentApplication`. It uses `SpringApplicationBuilder` to run the Spring Boot application, initializing the kernel service.

```Java
    // 继承自TodoParentApplication
    public class TodoKernelApplication extends TodoParentApplication {
    
        // 启动类
        public static void main(String[] args) {
            new SpringApplicationBuilder(TodoKernelApplication.class).run(args);
        }
    
    }
```

--------------------------------

### Check K3s Cluster Status (kubectl)

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Verifies the status of K3s nodes and pods using the newly installed `kubectl` command.

```bash
kubectl get nodes -o wide
kubeadm get pod -n kube-system
```

--------------------------------

### Main Spring Boot Application for TODO Kernel Service

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/quick-start.adoc

Extends `TodoParentApplication` and serves as the main entry point for the TODO kernel service. It initializes and runs the Spring Boot application using `SpringApplicationBuilder`, demonstrating how to launch a specific service module.

```java
// 继承自TodoParentApplication
public class TodoKernelApplication extends TodoParentApplication {

    // 启动类
    public static void main(String[] args) {
        new SpringApplicationBuilder(TodoKernelApplication.class).run(args);
    }

}
```

--------------------------------

### Adding Spring Boot HBase Starter Dependency

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

Specifies the Maven dependency required to integrate HBase client capabilities with Spring Boot applications, enabling configuration management and Kerberos authentication.

```XML
<dependency>
    <groupId>group.idealworld.dew</groupId>
    <artifactId>hbase-starter</artifactId>
</dependency>
```

--------------------------------

### Importing Dew Framework Dependencies via Maven

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

This snippet demonstrates how to include Dew framework modules in a Maven project. It shows the parent dependency and how to add specific modules, along with developer and SCM information. The `parent-starter` simplifies version management by providing default versions for all Dew modules.

```xml
<!--引入Dew父依赖，也可以使用import方式-->
<parent>
    <groupId>group.idealworld.dew</groupId>
    <artifactId>parent-starter</artifactId>
    <!--生产环境请选择合适的版本!-->
    <version>${dew.version}</version>
</parent>
...
<dependencies>
    <!--引入需要的模块-->
    <dependency>
        <groupId>group.idealworld.dew</groupId>
        <artifactId>对应模块名，见下文</artifactId>
    </dependency>
</dependencies>
...
<!--开发者介绍-->
<developers>
    <developer>
        <name>...</name>
        <email>...</email>
    </developer>
</developers>
<!--SCM信息-->
<scm>
    <connection>...</connection>
    <developerConnection>...</developerConnection>
    <url></url>
</scm>
...
```

--------------------------------

### Install and Configure Prometheus Operator Helm Chart

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

This Helm command installs the `stable/prometheus-operator` chart, configuring Prometheus, Alertmanager, and Grafana. It sets up ingress hosts for all three components, enables persistent storage with 100Gi requests and specific label selectors, enables etcd service monitoring with TLS verification skipped, configures Grafana's admin password, default dashboards, ingress, sidecar for dashboards/datasources, and SMTP settings. All components are configured with a node selector for 'group=devops'.

```Shell
helm install stable/prometheus-operator --name dew-prometheus-operator --namespace devops --version=5.0.10
    --set kubelet.serviceMonitor.https=true
    --set prometheus.ingress.enabled=true
    --set prometheus.ingress.hosts={prometheus.dew.idealworld.group}
    --set alertmanager.ingress.enabled=true
    --set alertmanager.ingress.hosts={alertmanager.dew.idealworld.group}
    --set prometheusOperator.securityContext.runAsNonRoot=false
    --set prometheus.prometheusSpec.storageSpec.volumeClaimTemplate.spec.resources.requests.storage=100Gi
    --set alertmanager.alertmanagerSpec.storage.volumeClaimTemplate.spec.resources.requests.storage=100Gi
    --set prometheus.prometheusSpec.storageSpec.volumeClaimTemplate.spec.selector.matchLabels."component"="prometheus"
    --set alertmanager.alertmanagerSpec.storage.volumeClaimTemplate.spec.selector.matchLabels."component"="alertmanager"
    --set prometheus.prometheusSpec.secrets[0]=dew-prometheus-operator-etcd
    --set kubeEtcd.serviceMonitor.scheme=https
    --set kubeEtcd.serviceMonitor.insecureSkipVerify=true
    --set kubeEtcd.serviceMonitor.caFile="/etc/prometheus/secrets/dew-prometheus-operator-etcd/ca.crt"
    --set kubeEtcd.serviceMonitor.certFile="/etc/prometheus/secrets/dew-prometheus-operator-etcd/peer.crt"
    --set kubeEtcd.serviceMonitor.keyFile="/etc/prometheus/secrets/dew-prometheus-operator-etcd/peer.key"
    --set grafana.enabled=true
    --set grafana.adminPassword=Dew123456
    --set grafana.defaultDashboardsEnabled=true
    --set grafana.ingress.enabled=true
    --set grafana.ingress.hosts={grafana.dew.idealworld.group}
    --set grafana.sidecar.dashboards.enabled=true
    --set grafana.sidecar.dashboards.searchNamespace="devops"
    --set grafana.sidecar.dashboards.label=grafana_dashboard
    --set grafana.sidecar.datasources.enabled=true
    --set grafana.sidecar.datasources.searchNamespace="devops"
    --set grafana.sidecar.datasources.label=grafana_datasource
    --set grafana.'grafana\\.ini'.smtp.enabled="true"
    --set grafana.'grafana\\.ini'.smtp.host="smtp.163.com:25"
    --set grafana.'grafana\\.ini'.smtp.user=XXXXX@163.com
    --set grafana.'grafana\\.ini'.smtp.password=XXXXX
    --set grafana.'grafana\\.ini'.smtp.from_address="XXXXX@163.com"
    --set grafana.'grafana\\.ini'.smtp.skip_verify=true
    --set grafana.'grafana\\.ini'.server.root_url="http://grafana.dew.idealworld.group"
    --set grafana.persistence.enabled=true
    --set grafana.persistence.existingClaim=grafana
    --set prometheusOperator.nodeSelector.group=devops
    --set alertmanager.alertmanagerSpec.nodeSelector.group=devops
    --set prometheus.prometheusSpec.nodeSelector.group=devops
    --set kube-state-metrics.nodeSelector.group=devops
    --set grafana.nodeSelector.group=devops
```

--------------------------------

### Common Library Maven Dependencies for Dew Boot Starter and JPA

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

This `pom.xml` snippet for the common library module illustrates the inclusion of `boot-starter` for core Dew framework capabilities and `spring-boot-starter-data-jpa` for Spring Data JPA support, enabling database interaction.

```XML
    <!-- ... -->
    
    <dependencies>
        <dependency>
            <groupId>group.idealworld.dew</groupId>
            <artifactId>boot-starter</artifactId>
        </dependency>
        <!-- 添加JPA支持  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
    </dependencies>
    
    <!-- ... -->
```

--------------------------------

### Usage Examples of Dew Common Utilities

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

This snippet demonstrates how to use various utility functions provided by the `Dew-Common` package. These include converting JSON to Java objects, copying Bean properties, performing asymmetric encryption, making HTTP GET requests, and validating mobile phone numbers. All `Dew Common` functions are accessed through the `$` prefix.

```java
// Dew Common 功能均以 $ 开始，如:

//Json转成Java对象:
$.json.toObject(json,JavaModel.class)
//Json字符串转成List对象
$.json.toList(jsonArray, JavaModel.class)
//Bean复制
$.bean.copyProperties(ori, dist)
//获取Class的注解信息
$.bean.getClassAnnotation(IdxController.class, TestAnnotation.RPC.class)
//非对称加密
$.encrypt.Asymmetric.encrypt(d.getBytes("UTF-8"), publicKey, 1024, "RSA")
//Http Get
$.http.get("https://httpbin.org/get")
//验证手机号格式是否合法
$.field.validateMobile("18657120000")
//...
```

--------------------------------

### Root Maven POM Configuration for Dew Parent Starter

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

This snippet shows the root `pom.xml` file, demonstrating how to inherit from Dew's `parent-starter`. This parent POM provides common dependencies and build configurations for Dew-based projects.

```XML
    <!-- 引用 Dew的 parent-starter -->
    <parent>
        <groupId>group.idealworld.dew</groupId>
        <artifactId>parent-starter</artifactId>
        <version>...</version>
    </parent>
    
    <!-- ... -->
```

--------------------------------

### Maven Dependency for Dew Cluster Module

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/framework/user-manual.adoc

To enable Dew's cluster functionalities, such as distributed caching, maps, locks, and messaging, the `boot-starter` module must be included as a Maven dependency. This module provides the foundational components for integrating Dew's cluster capabilities into your application.

```xml
<dependency>
    <groupId>group.idealworld.dew</groupId>
    <artifactId>boot-starter</artifactId>
</dependency>
```

--------------------------------

### Java Example for Leader Election Service

Source: https://github.com/gudaoxuri/dew/blob/master/docs/index.html

This Java example illustrates how to use Dew's ClusterElection service. It demonstrates instantiating a typed leader election service (e.g., 'fun1') and then conditionally executing code blocks only if the current node is identified as the leader for that specific election type, enabling distributed coordination.

```Java
// 实例化fun1类型的领导者选举，Redis的实现支持多类型领导者
ClusterElection electionFun1 = Dew.cluster.election.instance("fun1");
// ...
if (electionFun1.isLeader()) {
   // 当前节点是fun1类型的领导者
   // ...
}
```

--------------------------------

### Check Kubernetes Cluster Component Status

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Verifies the status of Kubernetes cluster components.

```bash
kubectl get cs
```

--------------------------------

### Retrieve K3s Server Token

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Retrieves the K3s server token, which is necessary for agent nodes to join the cluster.

```bash
cat /var/lib/rancher/k3s/server/token
```

--------------------------------

### Scale Application Replicas

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/user-manual.adoc

Outlines the Maven command for scaling an application, including parameters for setting the number of replicas, enabling auto-scaling, and configuring auto-scaling limits.

```bash
# 基础命令
mvn -P devops dew:scale

# ====================== 附加参数 ======================
# dew_devops_scale_replicas                    # 伸缩Pod数量
# dew_devops_scale_auto                        # 是否启用自动伸缩
# dew_devops_scale_auto_minReplicas            # 自动伸缩Pod数下限
```

--------------------------------

### Configure Docker for K3s Compatibility

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Modifies Docker daemon configuration to use `cgroupfs` as the cgroup driver, which is required for K3s.

```bash
# Docker 修改
# K3s使用的是cgroupfs
# 去掉 /etc/docker/daemon.json 中的 "exec-opts": ["native.cgroupdriver=systemd"]
systemctl daemon-reload
systemctl restart docker
```

--------------------------------

### Create Kubernetes Namespaces

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Creates new namespaces (e.g., 'nginx-ingress', 'devops') within the Kubernetes cluster for logical separation of resources.

```bash
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Namespace
metadata:
  name: nginx-ingress
  labels:
    name: nginx-ingress
EOF
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Namespace
metadata:
  name: devops
  labels:
    name: devops
EOF
```

--------------------------------

### Check K3s Cluster Status (k3s kubectl)

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/install.adoc

Verifies the status of K3s nodes using the bundled `k3s kubectl` command.

```bash
k3s kubectl get nodes -o wide
```

--------------------------------

### Execute Parallel Deployment with Maven

Source: https://github.com/gudaoxuri/dew/blob/master/docs/src/main/asciidoc/_chapter/devops/user-manual.adoc

Demonstrates how to use Maven's parallel execution feature (`-T`) to speed up compilation and deployment processes.

```bash
mvn -T 1C deploy
```