Eureka health status

README.md

@@ -44,6 +44,7 @@
   * [SonarQube](#sonarqube)
   * [Elasticsearch Hit Count](#elasticsearch-hit-count)
   * [GitHub Issue Count](#github-issue-count)
+  * [Eureka Health Status](#eureka-health-status)
 * [Available Themes](#available-themes)
   * [light](#light)
   * [dark](#dark)
@@ -312,6 +313,36 @@ import GitHubIssueCount from '../components/github/issue-count'
 * `repository`: Name of the repository
 * `authKey`: Credential key, defined in [auth.js](./auth.js)
 
+### [Eureka Health Status](./components/widgets/eureka/health-status.js)
+
+#### Example
+
+```javascript
+import EurekaHealthStatus from '../components/widgets/eureka/health-status'
+
+<EurekaHealthStatus
+  title='Eureka Health Status'
+  url='http://127.0.0.1:8080/'
+  eurekaQuery='http://eurekahost:8761'
+  healthQuery='/management/health'
+  appsQuery='/eureka/apps'
+  appNamePattern='SERVICE'
+  minimumInstances={2}
+/>
+```
+
+#### props
+
+* `title`: Widget title (Default: `Eureka Health Status`)
+* `interval`: Refresh interval in milliseconds (Default: `360000`)
+* `url`: Cross Origin Service URL
+* `eurekaQuery`: Eureka Server URL
+* `healthQuery`: Relative Path to Spring Boot Actuator Health endpoint
+* `appsQuery`: Relative Path to Eureka Apps API endpoint [Eureka REST operations](https://github.com/Netflix/eureka/wiki/Eureka-REST-operations)
+* `authKey`: Credential key, defined in [auth.js](./auth.js)
+* `appNamePattern`: Name pattern the service-names have to start with
+* `minimumInstances`: Number of instances for each service which are expected to run to be fine (Default: `2`)
+
 ## Available Themes
 
 ### [light](./styles/light-theme.js)

components/widgets/eureka/health-status.js

@@ -0,0 +1,168 @@
+import { Component } from 'react'
+import fetch from 'isomorphic-unfetch'
+import yup from 'yup'
+import Widget from '../../widget'
+import Table, { Th, Td } from '../../table'
+import { basicAuthHeader } from '../../../lib/auth'
+import styled from 'styled-components'
+
+const schema = yup.object().shape({
+  url: yup.string().url().required(),
+  interval: yup.number(),
+  eurekaQuery: yup.string().required(),
+  appsQuery: yup.string().required(),
+  healthQuery: yup.string().required(),
+  title: yup.string(),
+  minimumInstances: yup.number(),
+  appNamePattern: yup.string(),
+  authKey: yup.string()
+})
+
+const EurekaDiv = styled.div`
+  background-color: ${props => props.hasError ? props.theme.palette.errorColor : props.theme.palette.canvasColor};
+`
+
+export default class EurekaHealthStatus extends Component {
+  static defaultProps = {
+    interval: 1000 * 60 * 60,
+    title: 'Eureka Health Status',
+    minimumInstances: 2,
+    appNamePattern: ''
+  }
+
+  state = {
+    error: false,
+    loading: true,
+    appStatus: '',
+    infoMessage: ''
+  }
+
+  constructor (props, context) {
+    super(props, context)
+    this.checkInstanceCount = this.checkInstanceCount.bind(this)
+  }
+
+  componentDidMount () {
+    schema.validate(this.props)
+    .then(() => this.fetchInformation())
+    .catch((err) => {
+      console.error(`${err.name} @ ${this.constructor.name}`, err.errors)
+      this.setState({ error: true, loading: false })
+    })
+  }
+
+  componentWillUnmount () {
+    clearTimeout(this.timeout)
+  }
+
+  checkInstanceCount (appList) {
+    const { appNamePattern, minimumInstances } = this.props
+    let hasError = false
+    appList.forEach(function (entry) {
+      if ((appNamePattern.length === 0 || entry.name.startsWith(appNamePattern)) && entry.instance.length < minimumInstances) {
+        hasError = true
+      }
+    })
+    return hasError
+  }
+
+  async checkInstanceHealth (url, appNamePattern, appList) {
+    let hasError = false
+    for (var i = 0; i < appList.length; i++) {
+      const app = appList[i]
+      if (appNamePattern.length === 0 || app.name.startsWith(appNamePattern)) {
+        for (var j = 0; j < app.instance.length; j++) {
+          try {
+            const curInstance = app.instance[j]
+            let opts = {headers: { 'Accept': 'application/json', 'Content-Type': 'application/json' }}
+            const resHealth = await fetch(url + curInstance.healthCheckUrl, opts)
+            const healthJson = await resHealth.json()
+            hasError = healthJson.status !== 'UP'
+          } catch (error) {
+            hasError = true
+          }
+        }
+      }
+    }
+    return hasError
+  }
+
+  async fetchInformation () {
+    const { authKey, url, eurekaQuery, healthQuery, appsQuery, appNamePattern } = this.props
+    let opts = authKey ? { headers: basicAuthHeader(authKey) } : {}
+
+    try {
+      const res = await fetch(`${url}${eurekaQuery}${healthQuery}`, opts)
+      const json = await res.json()
+
+      let appStatus = ''
+      let infoMessage = ''
+      let hasError = json.status !== 'UP'
+
+      if (!hasError) {
+        opts = {headers: { 'Accept': 'application/json', 'Content-Type': 'application/json' }}
+
+        try {
+          const resApps = await fetch(`${url}${eurekaQuery}${appsQuery}`, opts)
+          const jsonApps = await resApps.json()
+
+          hasError = jsonApps.applications.apps__hashcode.includes('DOWN')
+
+          const appsStatus = jsonApps.applications.apps__hashcode.split('_')
+          if (appsStatus.length > 0 && appsStatus.length < 4) {
+            appStatus = `${appsStatus[0]}: ${appsStatus[1]}`
+          } else {
+            appStatus = `${appsStatus[0]}: ${appsStatus[1]} - ${appsStatus[2]}: ${appsStatus[3]}`
+          }
+
+          if (!hasError) {
+            hasError = this.checkInstanceCount(jsonApps.applications.application)
+            if (hasError) {
+              infoMessage = 'Instance redundancy failed'
+            }
+          }
+
+          if (!hasError) {
+            hasError = await this.checkInstanceHealth(url, appNamePattern, jsonApps.applications.application)
+            if (hasError) {
+              infoMessage = 'App health check failed'
+            }
+          }
+        } catch (error) {
+          hasError = true
+        }
+      } else {
+        infoMessage = 'Eureka health failed'
+      }
+      this.setState({ appStatus, infoMessage, hasError, error: false, loading: false })
+    } catch (error) {
+      this.setState({ error: true, loading: false })
+    } finally {
+      this.timeout = setTimeout(() => this.fetchInformation(), this.props.interval)
+    }
+  }
+
+  render () {
+    const { error, loading, appStatus, infoMessage, hasError } = this.state
+    const { title } = this.props
+
+    return (
+      <Widget title={title} loading={loading} error={error}>
+        <EurekaDiv hasError={hasError}>
+          <Table>
+            <tbody>
+              <tr>
+                <Th>Apps</Th>
+                <Td>{appStatus}</Td>
+              </tr>
+              <tr>
+                <Th>Info</Th>
+                <Td>{infoMessage}</Td>
+              </tr>
+            </tbody>
+          </Table>
+        </EurekaDiv>
+      </Widget>
+    )
+  }
+}