mgfy: A command line tool for quick inspection of MongoDB

mgfy (short for magnify) is built to be a quick and easy way to get information from MongoDB without leaving the terminal. Have you ever forgotten the precise name of the collection you need to write to, wanted to know how much disk space is being used, or just needed an example document to remember the schema that you're working with? That's exactly what mgfy does.

Installation

Right now mgfy can only be installed using the Rust Toolchain. Like all other binary crates, it can be installed with:

cargo install mgfy

Connections

mgfy allows you to define and save parameters to easily switch between separate connections. Each connection is defined by the following fields:

Field	Description
name	A unique name for the connection; this will be used to specify which connection to use in subsequent commands
host	hostname used in the connection string (e.g. "localhost")
port	port used in the connection string (e.g. 27017, MongoDB's default
protocol	The first portion of the connection string (default: "mongodb")
default	Flag for whether this should be the default connection

There are a few commands for managing connections, they are:

1. create-connection: uses the specified parameters in creating a new connection
2. list-connections: lists the connections that have been saved
3. TODO remove-connection: deletes a saved connection
4. TODO set-default-connection: sets the named connection to be the default

Usage

There are a number of commands that are built into mgfy so far:

1. estimate-document-count: will return the document count from the collection metadata
2. example: gets an example document from the collection without filtering
3. exmaple-filtered: gets an example document from the collection after filtering on the user-provided query
4. list-collection-details: returns the name, document count, size, and allocated storage for each collection in a database
5. list-collections: returns the name of all the collections in a database
6. list-databases: returns all of the database names

Here's the help text:

$ mgfy -h
A command line tool for inspecting MongoDB

Usage: mgfy [OPTIONS] <COMMAND>

Commands:
  create-connection        Create a new connection
  estimate-document-count  Returns the document count in the metadata for the collection
  example                  Get an example document
  example-filtered         Get an example document after filtering
  list-collection-details  Get detailed information on each collection
  list-collections         List the collections in a database
  list-connections         List connections
  list-databases           List the databases
  help                     Print this message or the help of the given subcommand(s)

Options:
  -n, --name <NAME>  Name of the connection to use (see list-connections command)
  -h, --help         Print help
  -V, --version      Print versio

Filtering

Getting Rust to interpret an input string as JSON is not trivial. The following is a working example:

mgfy example-filtered foo bar '{"Hello": {"$exists": true}}'