Method _startChild

lib/code-caller.js:221–262

()

    }

    _startChild() {
        debug(`enter _startChild(), state: ${String(this.state)}, uuid: ${this.uuid}`);
        this._checkState([CREATED]);
        load.startJob('python', this.uuid);
        activeCallers[this.uuid] = this;

        const cmd = 'python3';
        var pythonTrampoline;
        if (config.useWorkers) {
            pythonTrampoline = path.join(__dirname, 'python-caller-trampoline.py');
        } else {
            pythonTrampoline = path.join(__dirname, 'python-caller-trampoline-no-fork.py');
        }
        const args = ['-B', pythonTrampoline];
        const env = _.clone(process.env);
        // PYTHONIOENCODING might not be needed once we switch to Python 3.7
        // https://www.python.org/dev/peps/pep-0538/
        // https://www.python.org/dev/peps/pep-0540/
        env.PYTHONIOENCODING = 'utf-8';
        const options = {
            cwd: __dirname,
            stdio: ['pipe', 'pipe', 'pipe', 'pipe'], // stdin, stdout, stderr, and an extra one for data
            env,
        };
        this.child = child_process.spawn(cmd, args, options);
        debug(`started child pid ${this.child.pid}, uuid: ${this.uuid}`);

        this.child.stderr.setEncoding('utf8');
        this.child.stdout.setEncoding('utf8');
        this.child.stdio[3].setEncoding('utf8');

        this.child.stderr.on('data', this._handleStderrData.bind(this));
        this.child.stdout.on('data', this._handleStdoutData.bind(this));
        this.child.stdio[3].on('data', this._handleStdio3Data.bind(this));

        this.child.on('exit', this._handleChildExit.bind(this));
        this.child.on('error', this._handleChildError.bind(this));

        this.state = WAITING;
        this._checkState();
        debug(`exit _startChild(), state: ${String(this.state)}, uuid: ${this.uuid}`);
    }

    _handleStderrData(data) {
        debug(`enter _handleStderrData(), state: ${String(this.state)}, uuid: ${this.uuid}`);