mongoexec.js

a small command line tool to execute arbitrary commands on selected documents in one mongodb database collection

version: 0.1.10

usage

$ mongoexec <namespace> <execution> [ <selector> ... ]

whereas:

• namespace is <database>.<collection>
• execution is the name of an "execution" script (see below for more)
• selector is a db.collection.find() expression or the string representation of a documents _id

if no selector is given on command line, read these from stdin. in fact that gives the ability to combine mongoexecs (even on discrete databases) as in:

$ mongoexec products.answers ./get_id.js '{"price":{"$gt":42}}' | mongoexec products.answers ./reduce_price_by_ten_percent.js

obviously this serves as an example only, as it can be achieved shorter (on the same database) as:

$ mongoexec products.answers ./reduce_price_by_ten_percent.js '{"price":{"$gt":42}}'

selectors

selectors are db.collection.find() compatible expressions (encoded as JSON) or the hexadecimal string representation of a documents _id

sample selectors

select "active" documents:

{ "status" : "active" }

select documents named "foo*"

{ "name" : { "$regex" : "^foo" } }

select this specific document by it's _id (string)

5890935df162533fea1b49ee

execution scripts

execution script are node.js modules following this basic pattern:

module.exports = {
  exec: function (document, collection, callback) {
    var error = null;
    var response = null;
    // do something here with the document
    // use collection to execute commands
    callback(error, response);
  }
}

execution scripts are loaded with absolute path or relative to current working directory and .js file extension is required

$ mongoexec inventory.cars ./get_license_plate.js '{ "firstLicenseYear" : { "$lt" : "2016" }'

sample execution scripts

sample: printing the documents _id property:

module.exports = {
  exec: function (document, collection, callback) {
    console.log(document._id);
    var error = null;
    var response = { _id: document._id };
    callback(error, response);
  }
}

sample: delete a document

module.exports = {
  exec: function (document, collection, callback) {
    // remove by document _id, check for error and response
    collection.deleteOne({ _id: document._id }, function(err, obj) {
      if (err)
        callback(err, null);
      else
        callback(null, { removed: { _id: document._id } });
    });
  }
};

sample: update a (status) property

module.exports = {
  exec: function (document, collection, callback) {
    // update by document _id and response
    collection.updateOne(
        {'_id': document._id},
        { $set: { 'status': 'archived' } },
        { upsert: false },
        function (err, r) {
            if (err) {
                console.error(document._id, err);
                callback(err, null);
            } else {
                console.info(document._id, 'archived');
                callback(null, { updated: document._id, to: 'archived' });
            }

        }
    );
  }
};

install

$ npm install --global mongoexec.js
$ mongoexec

TODO (required fixes)

• none

TODO (functionals)

• eventualy this should also be a npm module package (main: ./lib/...)
• read executions (and? selectors) from file
• swap order of command line arguments? (to: selector execution)
• take decision on final stdin handling (see the options in the code)
• pass db instead or additionaly to collection into the execution?
• pass document as an object with self-saving, updating etc. methods?
• command line options: --verbose, --help, --version
• command line option: --dryrun (how can this be achieved? any handy driver option?)
• transport arguments to execution scripts?
• more modes than exec? (e.g. create)