1const boostrap = pool => {
2  app.use((req, res, next) => {
3    pool
4      .acquire()
5      .then(session => {
6        res.locals.db = session;
7        res.on('end', () => {
8          console.log('end : closing db session...');
9          if (session) {
10              session.close();
11              session = null;
12          };
13        });
14        res.on('close', () => {
15          console.log('close : closing db session...');
16          if (session) {
17              session.close();
18              session = null;
19          };
20        });
21        res.on('finish', () => {
22          console.log('finish : closing db session...');
23          if (session) {
24              session.close();
25              session = null;
26          };
27        });
28        next();
29      })
30      .catch(err => {
31        console.log('err : closing db session...');
32        if (session) {
33            session.close();
34            session = null;
35        };
36        res.status(500).send(err);
37      });
38  });
39
40

1const client = new OrientDBClient({
2  host: "odbhost",
3  db: "userDBName",
4  user: "userId",
5  password: "userPassword",
6  rootUser: "rootId",
7  rootPassword: "rootPassword",
8  pool: {
9    max: 200
10  },
11  logger: { debug: console.log.bind(null,"OrientDB: ") }
12});
13
14... bunch of stuff here, then :
15
16
17  client
18    .connect()
19    .then(() => {
20      return client.sessions({
21        name: "userDBName",
22        user: "userId",
23        password: "userPassword",
24        rootUser: "rootId",
25        rootPassword: "rootPassword",
26        pool: {
27          max: 25
28        },
29        logger: { debug: console.log.bind(null,"OrientDB: ") }
30      });
31  })
32  .then(pool => {
33    console.log('loading bootstrap pool ...')
34    boostrap(pool);
35  })
36  .catch(err => {
37    console.log(err);
38  });
39