Local file storage

Quix SaaS Platform
1

I want to use an in memory no sql db in a node (express) application within the Quix platform.

The no sql db uses a file as it’s backing store.
I’d like to push the file to local storage.

Can I access local storage from nodeJS or should I devise some mechanism to publish the db updates to a topic and then somehow read them from the topic on start?

2

It looks possible to run a python script from within node/express

Using the code below when i access the root (/) it prints Wrote to storage the first time and DB Exists 12.51 the second time.

So maybe I’ll try integrating this into my solution.

Express code (main.js)

var express = require('express');
const {spawn} = require('child_process');

const port = 80;

var app = express();

module.exports = app;

app.get('/', (req, res) => {

    var dataToSend;
    // spawn new child process to call the python script
    const python = spawn('python', ['quix_storage.py']);
        // collect data from script
        python.stdout.on('data', function (data) {
        console.log('Pipe data from python script ...');
        dataToSend = data.toString();
    });
    // in close event we are sure that stream from child process is closed
    python.on('close', (code) => {
        console.log(`child process close all stdio with code ${code}`);
        //send data to browser
        res.send(dataToSend)
    });

})
app.listen(port, () => console.log(`Server running at http://127.0.0.1:${port}`))

quix_storage.py

from quixstreams import LocalFileStorage

storage = LocalFileStorage()

if storage.contains_key("db"):
    print("DB Exists")
    print(storage.get("db"))

else:
    print("Wrote to storage")
    storage.set("db", 12.51)

dockerfile

FROM node

RUN apt-get update || : && apt-get install python -y
RUN apt-get install python3-pip -y

RUN pip install --no-cache-dir --upgrade pip && \
    pip install --no-cache-dir quixstreams==0.5.3

COPY --from=git /project /app
WORKDIR /app
RUN npm install
ENTRYPOINT node main.js
3

LocalFileStorage is a thin wrapper on top of reading and writing from and to disk. There are some nuances (such as MD5 hash check, python pickle for complex objects) that make it a bit more than straight reading the disk from file however.

Depending on your use case, you can do what you wrote above - assuming low load -, but I would only use it if you HAD TO, such as trying to expose a specific state via a web UI.

You might want to consider using a python web API rather than javascript based, so you can directly use the quixstreams library rather than relying on a inter-process communication via reading standard output.

1 Like