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Network Access with MicroPython on an ESP8266

In a previous post we have seen how to set up a WebREPL on a NodeMCU ESP8266 and create it’s own network. This is very handy in a lot of situations. In many other situations, however, there is already a network available for a device to join. With proper network access any machine on the network can use the NodeMCU. Let’s take a look at MicroPython networking and how we can leverage it to connect to the WebREPL interface from a different machine on the network.

Network Access

The first step is to get the NodeMCU ESP8266 connected to our network. We will need to do this from the serial connection since our WiFi settings will soon change. See my post here for how to setup a serial connection with the NodeMCU ESP8266. In taking a look at the networking documentation on the MicroPython site, we see that there is a network module available. MicroPython has made our lives easier, very nice!

With ssid as the name of the network, and password being the network password, we can get network access with the following commands:

import network
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect('ssid', 'password')

Entering each of those commands into the REPL should allow the NodeMCU ESP8266 to connect to the network.

Network Access

 

Test the Connection

If we give the device a moment or two to connect we can get the network configuration for the device with the ifconfig function.

wlan.ifconfig()

 

NodeMCU Network Config

Great! The ESP8266 is now has network access on the 10.0.0.31 network. The other numbers there are the network mask, gateway, and the DNS address, respectively. With the board connected we can enable the WebREPL interface and start the service.

Start WebREPL

Notice the two different IP addresses there. The 192.168.4.1 is the WiFi network the ESP8266 is generating and the 10.0.0.31 address is for the external network. The addresses themselves may be different on your own device based on your network.

Network Connection to WebREPL

Open the WebREPL client, as discussed in this post and use the IP address of the local network instead of the ESP8266 default 192.168.4.1 address. In this example I’ll input ws://10.0.0.31:8266/ into the address box to connect. Enter the password for the WebREPL that you created earlier and start entering Python commands!

WebREPL connection

Over in the terminal window you should also see a notification that there is a WebREPL connection.

Showing WebREPL Connection

Wrap-Up

In this short post we have seen here how we can obtain network access for our NodeMCU ESP8266 to an existing network and access it through the WebREPL client. Now you can access it through the serial interface, it’s own network, or a device on the same network. With this variety of ways to access an ESP8266 device

Follow me on Twitter @kenwalger to get the latest updates on my postings on MicroPython and IoT.

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MongoDB CLI Tools

I have discussed one of the GUI tools MongoDB offers, Compass, previously. Sometimes, however, using the command line interface (CLI) is required. MongoDB provides some very helpful CLI tools. Let’s have a quick look at what is included in the MongoDB installation package, and what the tools and files do.

Package Components

There are two main types of files which come included in the MongoDB download, process/service files and tools. The process files are the core components of the MongoDB system include the following:

Process
  • mongod, which is the core database process
  • mongos, which controls and routes queries in a sharded environment
  • mongo is the interactive, JavaScript based, MongoDB shell.
Service

In the Windows download there are some additional files for running and configuring MongoDB as a Windows Service.

These are the main applications you will find yourself using most often to get the server up and running (mongod) and interacting with the server in the mongo shell (mongo). It is possible to get some server information with shell database methods such as serverStatus() and stats(). However, there are some CLI tools which offer much more detailed information for us.

CLI Tools

There are a couple of different buckets in which the CLI tools fall; import/export and diagnostic tools. Let’s take a closer look:

Import/Export Tools

As with most databases, having a way to bring data into and out of the database is extremely useful. MongoDB is no different. Being a document database doesn’t mean that it can’t provide a way to utilize structured data when needed. Or, to provide a way to export it’s rich document data for use elsewhere.

MongoDB stores data on disk in BSON format and allows for the importing (restoration) and exporting (dumping) of files in this format with the following CLI tools.

  • mongodump, generates a BSON file from a running mongod server.
  • mongorestore allows for the restoration of the files

There also in an included application, bsondump, which will convert the BSON dump files into JSON files. Recall that BSON is a binary form of JSON and includes some important data features such as data typing, such as date, integer, long, double, and decimal.

For working with formats other than BSON, MongoDB provides for support for importing and exporting data in JSON, CSV, or TSV format. These can be especially useful when bringing in established relational data of many types.

  • mongoimport brings the JSON, CSV, or TSV formatted data into a running MongoDB database
  • mongoexport, yep you guessed it, exports the database data.
CLI Tools for Diagnosis

This is where the real workhorses come in for examining the health of your MongoDB server environment. The provided tools allow for the examination of the current operation of a MongoDB server. One can also look at, and capture, network traffic or manage LDAP configurations.

  • mongostat is great for a obtaining the overview status of a running mongod or mongos instance. For example, it can provide information regarding the number of inserts, queries, updates, or deletes and lots more.

    Mongostats
    Mongostat results while doing large inserts
  • mongotop looks at, at a collection level, the time for reading and writing of data. It provides, at a high level, a view of where Mongodb is spending it’s time.

    mongotop
    mongotop results while doing inserts
  • mongoperf checks disk performance
  • mongoreplay is pretty cool. It allows for, among other things, the capture of commands sent to a MongoDB instance and the ability to replay them in a different environment. This is very handy for testing and trouble shooting.
  • mongoldap allows for testing LDAP configuration options against LDAP server(s).
Other Tools

The last tool which comes in the MongoDB package is mongofiles which allows for interaction with GridFS objects. GridFS allows for the storage of files larger than the BSON limit of 16MB per document.

Conclusion

Graphical User Interfaces (GUI) are great, but sometimes you will find it necessary to use a CLI tool to really understand what is going on with your system. MongoDB provides a great assortment of tools to do just that. I would recommend having a look at some of them to expand your personal tool-kit.

Follow me on Twitter @kenwalger to get the latest updates on my postings.

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