jsl data refactor

packages/api/src/controllers/jsldata.js

@@ -1,6 +1,9 @@
 const fs = require('fs');
 const lineReader = require('line-reader');
+const { off } = require('process');
+const DatastoreProxy = require('../utility/DatastoreProxy');
 const getJslFileName = require('../utility/getJslFileName');
+const JsonLinesDatastore = require('../utility/JsonLinesDatastore');
 const socket = require('../utility/socket');
 
 function readFirstLine(file) {
@@ -19,76 +22,85 @@ function readFirstLine(file) {
   });
 }
 
-
 module.exports = {
-  openedReaders: {},
+  datastores: {},
 
-  closeReader(jslid) {
-    // console.log('CLOSING READER');
-    if (!this.openedReaders[jslid]) return Promise.resolve();
-    return new Promise((resolve, reject) => {
-      this.openedReaders[jslid].reader.close((err) => {
-        if (err) reject(err);
-        delete this.openedReaders[jslid];
-        resolve();
-      });
-    });
-  },
+  // closeReader(jslid) {
+  //   // console.log('CLOSING READER');
+  //   if (!this.openedReaders[jslid]) return Promise.resolve();
+  //   return new Promise((resolve, reject) => {
+  //     this.openedReaders[jslid].reader.close((err) => {
+  //       if (err) reject(err);
+  //       delete this.openedReaders[jslid];
+  //       resolve();
+  //     });
+  //   });
+  // },
 
-  readLine(readerInfo) {
-    return new Promise((resolve, reject) => {
-      const { reader } = readerInfo;
-      if (!reader.hasNextLine()) {
-        resolve(null);
-        return;
-      }
-      reader.nextLine((err, line) => {
-        if (readerInfo.readedSchemaRow) readerInfo.readedDataRowCount += 1;
-        else readerInfo.readedSchemaRow = true;
-        if (err) reject(err);
-        resolve(line);
-      });
-    });
-  },
+  // readLine(readerInfo) {
+  //   return new Promise((resolve, reject) => {
+  //     const { reader } = readerInfo;
+  //     if (!reader.hasNextLine()) {
+  //       resolve(null);
+  //       return;
+  //     }
+  //     reader.nextLine((err, line) => {
+  //       if (readerInfo.readedSchemaRow) readerInfo.readedDataRowCount += 1;
+  //       else readerInfo.readedSchemaRow = true;
+  //       if (err) reject(err);
+  //       resolve(line);
+  //     });
+  //   });
+  // },
 
-  openReader(jslid) {
-    // console.log('OPENING READER');
-    // console.log(
-    //   'OPENING READER, LINES=',
-    //   fs.readFileSync(path.join(jsldir(), `${jslid}.jsonl`), 'utf-8').split('\n').length
+  // openReader(jslid) {
+  //   // console.log('OPENING READER');
+  //   // console.log(
+  //   //   'OPENING READER, LINES=',
+  //   //   fs.readFileSync(path.join(jsldir(), `${jslid}.jsonl`), 'utf-8').split('\n').length
+  //   // );
+  //   const file = getJslFileName(jslid);
+  //   return new Promise((resolve, reject) =>
+  //     lineReader.open(file, (err, reader) => {
+  //       if (err) reject(err);
+  //       const readerInfo = {
+  //         reader,
+  //         readedDataRowCount: 0,
+  //         readedSchemaRow: false,
+  //         isReading: true,
+  //       };
+  //       this.openedReaders[jslid] = readerInfo;
+  //       resolve(readerInfo);
+  //     })
   //   );
-    const file = getJslFileName(jslid);
-    return new Promise((resolve, reject) =>
-      lineReader.open(file, (err, reader) => {
-        if (err) reject(err);
-        const readerInfo = {
-          reader,
-          readedDataRowCount: 0,
-          readedSchemaRow: false,
-          isReading: true,
-        };
-        this.openedReaders[jslid] = readerInfo;
-        resolve(readerInfo);
-      })
-    );
-  },
+  // },
 
-  async ensureReader(jslid, offset) {
-    if (this.openedReaders[jslid] && this.openedReaders[jslid].readedDataRowCount > offset) {
-      await this.closeReader(jslid);
+  // async ensureReader(jslid, offset) {
+  //   if (this.openedReaders[jslid] && this.openedReaders[jslid].readedDataRowCount > offset) {
+  //     await this.closeReader(jslid);
+  //   }
+  //   let readerInfo = this.openedReaders[jslid];
+  //   if (!this.openedReaders[jslid]) {
+  //     readerInfo = await this.openReader(jslid);
+  //   }
+  //   readerInfo.isReading = true;
+  //   if (!readerInfo.readedSchemaRow) {
+  //     await this.readLine(readerInfo); // skip structure
+  //   }
+  //   while (readerInfo.readedDataRowCount < offset) {
+  //     await this.readLine(readerInfo);
+  //   }
+  //   return readerInfo;
+  // },
+
+  async ensureDatastore(jslid) {
+    let datastore = this.datastores[jslid];
+    if (!datastore) {
+      datastore = new JsonLinesDatastore(getJslFileName(jslid));
+      // datastore = new DatastoreProxy(getJslFileName(jslid));
+      this.datastores[jslid] = datastore;
     }
-    let readerInfo = this.openedReaders[jslid];
-    if (!this.openedReaders[jslid]) {
-      readerInfo = await this.openReader(jslid);
-    }
-    readerInfo.isReading = true;
-    if (!readerInfo.readedSchemaRow) {
-      await this.readLine(readerInfo); // skip structure
-    }
-    while (readerInfo.readedDataRowCount < offset) {
-      await this.readLine(readerInfo);
-    }
-    return readerInfo;
+    return datastore;
   },
 
   getInfo_meta: 'get',
@@ -101,20 +113,8 @@ module.exports = {
 
   getRows_meta: 'get',
   async getRows({ jslid, offset, limit }) {
-    const readerInfo = await this.ensureReader(jslid, offset);
-    const res = [];
-    for (let i = 0; i < limit; i += 1) {
-      const line = await this.readLine(readerInfo);
-      if (line == null) break;
-      res.push(JSON.parse(line));
-    }
-    readerInfo.isReading = false;
-    if (readerInfo.closeAfterReadAndSendStats) {
-      await this.closeReader(jslid);
-      socket.emit(`jsldata-stats-${jslid}`, readerInfo.closeAfterReadAndSendStats);
-      readerInfo.closeAfterReadAndSendStats = null;
-    }
-    return res;
+    const datastore = await this.ensureDatastore(jslid);
+    return datastore.getRows(offset, limit);
   },
 
   getStats_meta: 'get',
@@ -126,12 +126,16 @@ module.exports = {
 
   async notifyChangedStats(stats) {
     console.log('SENDING STATS', JSON.stringify(stats));
-    const readerInfo = this.openedReaders[stats.jslid];
-    if (readerInfo && readerInfo.isReading) {
-      readerInfo.closeAfterReadAndSendStats = stats;
-    } else {
-      await this.closeReader(stats.jslid);
+    const datastore = this.datastores[stats.jslid];
+    if (datastore) await datastore.notifyChanged();
     socket.emit(`jsldata-stats-${stats.jslid}`, stats);
-    }
+
+    // const readerInfo = this.openedReaders[stats.jslid];
+    // if (readerInfo && readerInfo.isReading) {
+    //   readerInfo.closeAfterReadAndSendStats = stats;
+    // } else {
+    //   await this.closeReader(stats.jslid);
+    //   socket.emit(`jsldata-stats-${stats.jslid}`, stats);
+    // }
   },
 };

packages/api/src/proc/index.js

@@ -2,10 +2,12 @@ const connectProcess = require('./connectProcess');
 const databaseConnectionProcess = require('./databaseConnectionProcess');
 const serverConnectionProcess = require('./serverConnectionProcess');
 const sessionProcess = require('./sessionProcess');
+const jslDatastoreProcess = require('./jslDatastoreProcess');
 
 module.exports = {
   connectProcess,
   databaseConnectionProcess,
   serverConnectionProcess,
   sessionProcess,
+  jslDatastoreProcess,
 };

packages/api/src/proc/jslDatastoreProcess.js

@@ -0,0 +1,57 @@
+const childProcessChecker = require('../utility/childProcessChecker');
+const JsonLinesDatastore = require('../utility/JsonLinesDatastore');
+
+let lastPing = null;
+let datastore = new JsonLinesDatastore();
+
+function handlePing() {
+  lastPing = new Date().getTime();
+}
+
+function handleOpen({file }) {
+  handlePing();
+  datastore = new JsonLinesDatastore(file);
+}
+
+async function handleRead({ msgid, offset, limit }) {
+  handlePing();
+  const rows = await datastore.getRows(offset, limit);
+  process.send({ msgtype: 'response', msgid, rows });
+}
+
+function handleNotifyChanged() {
+  datastore.notifyChanged();
+}
+
+const messageHandlers = {
+  open: handleOpen,
+  read: handleRead,
+  ping: handlePing,
+  notifyChanged: handleNotifyChanged,
+};
+
+async function handleMessage({ msgtype, ...other }) {
+  const handler = messageHandlers[msgtype];
+  await handler(other);
+}
+
+function start() {
+  childProcessChecker();
+
+  setInterval(() => {
+    const time = new Date().getTime();
+    if (time - lastPing > 60 * 1000) {
+      process.exit(0);
+    }
+  }, 60 * 1000);
+
+  process.on('message', async (message) => {
+    try {
+      await handleMessage(message);
+    } catch (e) {
+      process.send({ msgtype: 'error', error: e.message });
+    }
+  });
+}
+
+module.exports = { start };

packages/api/src/utility/DatastoreProxy.js

@@ -0,0 +1,55 @@
+const { fork } = require('child_process');
+const uuidv1 = require('uuid/v1');
+
+class DatastoreProxy {
+  constructor(file) {
+    this.subprocess = null;
+    this.disconnected = false;
+    this.file = file;
+    this.requests = {};
+    this.handle_response = this.handle_response.bind(this);
+    this.handle_ping = this.handle_ping.bind(this);
+  }
+
+  // handle_response({ msgid, rows }) {
+  handle_response({ msgid, rows }) {
+    const [resolve, reject] = this.requests[msgid];
+    resolve(rows);
+    delete this.requests[msgid];
+  }
+
+  handle_ping() {}
+
+
+  async ensureSubprocess() {
+    if (!this.subprocess) {
+      this.subprocess = fork(process.argv[1], ['jslDatastoreProcess']);
+
+      // @ts-ignore
+      this.subprocess.on('message', ({ msgtype, ...message }) => {
+        // if (this.disconnected) return;
+        this[`handle_${msgtype}`](message);
+      });
+      this.subprocess.on('exit', () => {
+        // if (this.disconnected) return;
+        this.subprocess = null;
+      });
+      this.subprocess.send({ msgtype: 'open', file: this.file });
+    }
+    return this.subprocess;
+  }
+
+  async getRows(offset, limit) {
+    await this.ensureSubprocess();
+    const msgid = uuidv1();
+    const promise = new Promise((resolve, reject) => {
+      this.requests[msgid] = [resolve, reject];
+      this.subprocess.send({ msgtype: 'read', msgid, offset, limit });
+    });
+    return promise;
+  }
+
+  async notifyChanged() {}
+}
+
+module.exports = DatastoreProxy;

packages/api/src/utility/JsonLinesDatastore.js

@@ -0,0 +1,115 @@
+const lineReader = require('line-reader');
+
+class JsonLinesDatastore {
+  constructor(file) {
+    this.file = file;
+    this.readerInfo = {
+      reader: null,
+      readedDataRowCount: 0,
+      readedSchemaRow: false,
+      isReading: false,
+      closeAfterRead: null,
+      closeAfterReadPromise: null,
+    };
+  }
+
+  async closeReader() {
+    if (!this.readerInfo) return Promise.resolve();
+    return new Promise((resolve, reject) => {
+      this.readerInfo.reader.close((err) => {
+        if (err) reject(err);
+        resolve();
+      });
+    });
+  }
+
+  async notifyChanged() {
+    if (this.readerInfo && this.readerInfo.isReading) {
+      if (this.readerInfo.closeAfterRead) {
+        return this.readerInfo.closeAfterReadPromise;
+      }
+      const promise = new Promise((resolve, reject) => {
+        this.readerInfo.closeAfterRead = resolve;
+      });
+      this.readerInfo.closeAfterReadPromise = promise;
+      return promise;
+    } else {
+      await this.closeReader();
+    }
+  }
+
+  async openReader() {
+    return new Promise((resolve, reject) =>
+      lineReader.open(this.file, (err, reader) => {
+        if (err) reject(err);
+
+        const readerInfo = {
+          reader,
+          readedDataRowCount: 0,
+          readedSchemaRow: false,
+          isReading: true,
+          closeAfterRead: null,
+          closeAfterReadPromise: null,
+        };
+        this.readerInfo = readerInfo;
+        resolve(readerInfo);
+      })
+    );
+  }
+
+  readLine(readerInfo) {
+    return new Promise((resolve, reject) => {
+      const { reader } = readerInfo;
+      if (!reader.hasNextLine()) {
+        resolve(null);
+        return;
+      }
+      reader.nextLine((err, line) => {
+        if (readerInfo.readedSchemaRow) readerInfo.readedDataRowCount += 1;
+        else readerInfo.readedSchemaRow = true;
+        if (err) reject(err);
+        resolve(line);
+      });
+    });
+  }
+
+  async ensureReader(offset) {
+    if (this.readerInfo && this.readerInfo.readedDataRowCount > offset) {
+      await this.closeReader();
+    }
+    let readerInfo = this.readerInfo;
+    if (!readerInfo || !readerInfo.reader) {
+      readerInfo = await this.openReader();
+    }
+    readerInfo.isReading = true;
+    if (!readerInfo.readedSchemaRow) {
+      await this.readLine(readerInfo); // skip structure
+    }
+    while (readerInfo.readedDataRowCount < offset) {
+      await this.readLine(readerInfo);
+    }
+    return readerInfo;
+  }
+
+  async getRows(offset, limit) {
+    const readerInfo = await this.ensureReader(offset);
+    const res = [];
+    for (let i = 0; i < limit; i += 1) {
+      const line = await this.readLine(readerInfo);
+      if (line == null) break;
+      res.push(JSON.parse(line));
+    }
+    readerInfo.isReading = false;
+    if (readerInfo.closeAfterRead) {
+      await this.closeReader();
+      // socket.emit(`jsldata-stats-${jslid}`, readerInfo.closeAfterReadAndSendStats);
+      const resolve = readerInfo.closeAfterRead;
+      readerInfo.closeAfterRead = null;
+      readerInfo.closeAfterReadPromise = null;
+      resolve();
+    }
+    return res;
+  }
+}
+
+module.exports = JsonLinesDatastore;