Basic version of GraphQL server returning latest home sensors reading

Author: nrdcp

.eslintrc.json

@@ -0,0 +1,6 @@
+{
+  "extends": "airbnb-base",
+  "rules": {
+    "max-len": 1,
+  }
+}

package-lock.json

@@ -10,6 +10,15 @@
   "dependencies": {
     "@google-cloud/bigquery": "^4.7.0",
     "apicache": "^1.5.3",
-    "express": "^4.17.1"
+    "apollo-server-express": "^2.12.0",
+    "apollo-server-plugin-response-cache": "^0.4.1",
+    "cors": "^2.8.5",
+    "deepmerge": "^4.2.2",
+    "express": "^4.17.1",
+    "graphql": "^15.0.0"
+  },
+  "devDependencies": {
+    "eslint": "^6.8.0",
+    "eslint-config-airbnb-base": "^14.1.0"
   }
 }

package.json

@@ -1,18 +1,32 @@
-# nrdcp API
+# nrdcp GraphQL API
 
-## endpoints
-
-### /v1/home-sensor/latest
-
-## setting up
+## credentials
 
 check correct project is set with `gcloud config list project`
 if not, update with `export GOOGLE_CLOUD_PROJECT=$(gcloud config get-value core/project)`
 
 associate with service account (needs at least BigQuery User and Viewer permissions)
 `export GOOGLE_APPLICATION_CREDENTIALS=/Users/${USER}/gcp/keys/big-query-api-key.json`
 
+## run locally
+
 install dependencies `npm install`
+run server `npm start`
+navigate to `http://localhost:8080/graphql`
+
+## available data
+
+latest Home Sensor reading (SQL query directly on BiqQuery)
+
+```
+query {
+  latestSensorReading {
+    temperature,
+    humidity,
+    timestamp
+  }
+}
+```
 
 ## build image
 
@@ -30,12 +44,10 @@ gcloud run deploy nrdcp-api \
   --allow-unauthenticated
 ```
 
-## todo
+## TODO
 
-* explore cloudbuild config
-* cors
-* git
-* logging
+* Logging
+* Cloudbuild from git hash
 
 
 

readme.md

@@ -0,0 +1,30 @@
+const { BigQuery } = require('@google-cloud/bigquery');
+
+class HomeSensorAPI {
+  constructor() {
+    this.bigqueryClient = new BigQuery();
+  }
+
+  async getLatestReading() {
+    const sqlQuery = `SELECT
+      temp as temperature,
+      humd as humidity,
+      UNIX_MILLIS(TIMESTAMP(time)) as timestamp
+      FROM pi3_dht22_dataset.dht22_data tbl
+      ORDER BY tbl.time DESC
+      LIMIT 1`;
+
+    const queryOptions = {
+      query: sqlQuery,
+      location: 'US',
+    };
+
+    const [rows] = await this.bigqueryClient.query(queryOptions);
+
+    return({
+      data: rows[0],
+    });
+  }
+}
+
+module.exports.HomeSensorAPI = HomeSensorAPI;

src/data-sources/home-sensor.js

@@ -0,0 +1,8 @@
+
+const { HomeSensorAPI } = require('./home-sensor');
+
+const getDataSources = () => ({
+  homeSensorAPI: new HomeSensorAPI(),
+});
+
+module.exports.getDataSources = getDataSources;

src/data-sources/index.js

@@ -0,0 +1,30 @@
+const { gql } = require('apollo-server-express');
+
+const typeDefs = gql`
+  extend type Query {
+    latestSensorReading: SensorReading!,
+  }
+
+  type SensorReading {
+    temperature: String,
+    humidity: String,
+    timestamp: Float,
+  }
+`;
+
+const resolvers = {
+  Query: {
+    latestSensorReading: async (parent, args, { dataSources }, info) => {
+      info.cacheControl.setCacheHint({ maxAge: 300, scope: 'PUBLIC' });
+
+      const response = await dataSources.homeSensorAPI.getLatestReading();
+
+      return response.data || {};
+    },
+  },
+};
+
+module.exports = {
+  typeDefs,
+  resolvers,
+};

src/graphql-modules/home-sensor.js

@@ -0,0 +1,18 @@
+const deepmerge = require('deepmerge');
+const { gql } = require('apollo-server-express');
+
+const {
+  resolvers: homeSensorResolvers,
+  typeDefs: homeSensorTypeDefs,
+} = require('./home-sensor');
+
+const queryTypeDefs = gql`
+  type Query {
+    _empty: String
+  }
+`;
+
+module.exports = {
+  typeDefs: [queryTypeDefs, homeSensorTypeDefs],
+  resolvers: deepmerge({}, homeSensorResolvers),
+};

src/graphql-modules/index.js

@@ -1,19 +1,30 @@
 const express = require('express');
-const apicache = require('apicache');
+const cors = require('cors');
+const responseCachePlugin = require('apollo-server-plugin-response-cache');
+const { ApolloServer } = require('apollo-server-express');
 
-const { homeSensorLatestHandler } = require('./home-sensor');
+const { getDataSources } = require('./data-sources');
+const { typeDefs, resolvers } = require('./graphql-modules');
 
 const app = express();
-const cache = apicache.middleware;
 
 app.get('/', (req, res) => {
   res.send('api I am');
 });
 
-app.get('/v1/home-sensor/latest', cache('10 minutes'), homeSensorLatestHandler);
-
 const port = process.env.PORT || 8080;
 
+const apollo = new ApolloServer({
+  typeDefs,
+  resolvers,
+  dataSources: getDataSources,
+  plugins: [responseCachePlugin()],
+});
+
+app.use(cors());
+
+apollo.applyMiddleware({ app, path: '/graphql' });
+
 app.listen(port, () => {
   console.log('Listening on port', port);
 });