Deploy Machine Learning Models in a Production environment as APIs (Python Flask + Visual Studio)

Intelligent application building basically consist of integrating machine learning based predictive components for the apps and systems. Mostly data scientists or the AI engineers are accountable of building these machine learning models.

When it comes to integration and deployment in production environment, the problem occurs with platform dependency. Most of the data scientists and AI engineers are pretty comfortable with python or R and they develop their models with them, though the rest of the system would be on .NET or Java based application.

One of the best approaches to connect these components together is deploying the ML predictive module as a web API and calling the API through the application. When it comes to APIs any programmer can work with it when they have the API definition.

Flask is a small and powerful web framework for Python. It’s easy to learn and simple to use, enabling you to build your web app in a short amount of time. Visual Studio provides an easy way to create Python flask web applications through it’s templates. Here’s the steps I’ve gone through for deploying the ML experiment as a REST API.

01. Create the machine learning model, train, tune and evaluate it.

Here what I’ve done is a simple linear regression for predicting the monthly salary according to the years of experience. Sci-kit learn python library has been used for performing the regression operation. The dataset used for the experiment is from SuperDataScience. 

The code is available in the GitHub repository .

02. Creating the pickle

When you deploy the predictive model in production environment, no need of training the model with code again and again. Python has a built-in method of persisting data called pickle. The pickle module can serialize objects or data into a file that we can save and load from. You can just use the pickle as a binary reference generating the output.  scikit-learn has their own model persistence method we will use: joblib. This is more efficient to use with scikit-learn models due to it being better at handling larger numpy arrays that may be stored in the models.

03. Create a Python Flask web application.

Simply go for Visual Studio. (I’m using VS2017 which comes with python by default) Select web project. The step by step guide is here.  I would recommend you to go with option 2 mentioned in the blog because it reduces lot of unnecessary overhead.

For the safe side, use python virtual environments. It would avoid many hassles occurs with library dependencies. I’ve used anaconda environment as the base of virtual environment.

04. Create the API.

Create a new python file in your project and set it as the startup file. (In my case MLService.py is the startup file which contains the API code). The pickle file that contains the model binaries is the only dependency the API is getting when it is deployed.

Here the API operates through POST methods which accepts the input in JSON.

04. Run & Test

You can run the API and test by sending POST requests to the URL with a JSON body. Here I’ve used postman to send a POST request and it gives me the predicted salary for the entered number of months.

You can access the whole code of the project through my GitHub repo here.

    Do comment if you have any suggestion to change the API structure.

Handling Big snakes on Visual Studio

In the last post we discuss on setting up a Windows rig for deep learning. If you still haven’t setup your machine, go do it first: D

After getting the so called big snakes; python and anaconda in the machine, we should have a proper IDE for coding.

There are many good IDEs you can use in Windows environment to code in python. Pycharm, Spyder are some popular tools.

If you familiar with Visual Studio, the so-called father of all IDEs, python works smoothly with VS. There are few configurations need to be done.

No need to purchase Visual Studio enterprise or ultimate. The freely available Visual Studio Community edition works fine. In 2017 version python comes along side with the default installation options. For the later versions you need to install Python Tools for Visual Studio (PTVS) separately.

https://docs.microsoft.com/en-us/visualstudio/python/python-in-visual-studio

Refer this guide for more details.

The python environments configured to machines can be seen from ‘Python Environments’ pane of Visual Studio. (If it is not there go for Tools -> Python -> Python Environments)

By default, your Anaconda environment and default python environment should be there. First Refresh those environments to support intelliSense and grab the installed libraries for the DB.

For our deep learning experimentations, we configured a separate python environment before. To add that environment for visual studio follow the following steps.

01. Click Custom on ‘Python environments’

02. Go for anaconda environments and activate your pre-configured environment for deep learning (Mine is tensorflow-gpu)

03. Copy the interpreter path of the environment

04. Insert it for the interpreter path and click “auto detect’. Visual Studio will detect the rest

05. Click Apply

It may take few minutes to refresh the packages as well as the intelliSense. Make the configured environment your default and open the interactive. You are good to go 😊

Natural Language Processing with Python + Visual Studio

Human Language is one of the most complicated phenomena to interpret for machines. Comparing to artificial languages like programming languages and mathematical notations, natural languages are hard to notate with explicit rules. Natural Language Processing, AKA Computational Linguistics enable computers to derive meaning from human or natural language input.

When it comes to natural language processing, text analysis plays a major role. One of the major problems we have to face when processing natural language is the computation power. Working with big corpus and chunking the textual data into n-grams need a big processing power. All mighty cloud; the ultimate savior comes handy in this application too.

Let’s peep into some of the cool tools you can use in your developments. In most of the cases, you don’t want to get the hassle of developing from the scratch. There are plenty of APIs and libraries that you can directly integrate with your system.

If you think, you wanna go from scratch and do some enhancements, there’s the space for you too. 😊

Text Analytics APIs

Microsoft text analytics APIs are set of web services built with Azure Machine Learning. Many major tasks found in natural language processing are exposed as web services through this. The API can be used to analyze unstructured text for tasks such as sentiment analysis, key phrase extraction, language detection and topic detection. No hard rules are training loads. Just call the API from your C# or python code. Refer the link below for more info.

https://docs.microsoft.com/en-us/azure/machine-learning/machine-learning-apps-text-analytics

Process natural language from the scratch!

Python! Yeah. that’s it! Among many languages used for programming, python comes handy with many pre-built packages specifically built for natural language processing.

Obviously, python works well with unix systems. But now the best IDE in town; Visual Studio comes with a toolset for python which enable you to edit, debug and compile python scripts using your existing IDE.  You should have Visual Studio 2015 (Community edition, professional or enterprise) for installing the python tools. (https://www.visualstudio.com/vs/python/)

Here I’ve used NLTK (Natural Language Tool Kit) for the task. One of the main advantage with NLTK is, it comes with dozens of built in corpora and trained models.

These are the Language processing tasks and corresponding NLTK modules with examples of functionality comes with that.

Source – http://www.nltk.org/book/ch00.html

For running python NLTK for the first time you may need to download the nltk_data. Go for the python interactive console and install the required data from the popping up NLTK downloader. (Use nltk.download()  for this task)

Here’s a little simulation of natural language processing tasks done using NLTK. Code snippets are commented for easy reading. 😊

import nltk
from nltk.corpus import treebank
from nltk.corpus import stopwords

#Sample sentence used for processing
sentence = """John came to office at eight o'clock on Monday morning & left the office with Arthur bit early."""

#Tokenizing the sentence into words 
word_tokens = nltk.word_tokenize(sentence)
#Tagging words
tagged_words = nltk.pos_tag(word_tokens)
#Identify named entities
named_entities = nltk.chunk.ne_chunk(tagged_words)

#Removing the stopwords from the text - Predefined stopwords in English have been used.
stop_words = set(stopwords.words('english'))
filtered_sentence = [w for w in word_tokens if not w in stop_words]

filtered_sentence = []

for w in word_tokens:
    if w not in stop_words:
        filtered_sentence.append(w)

print('Sentence - ' + sentence)
print('Word tokens - ')
print(word_tokens)
print('Tagged words - ')
print(tagged_words)
print('Named entities - ')
print(named_entities)
print('Word tokens - ')
print(word_tokens)
print('Filtered sentence - ')
print(filtered_sentence)

 

The output after executing the script should be like this.

You can Improve these basics to build Named Entity Recognizer and many more…

Try processing the language you read and speak… 😉

SQL support in R tools for Visual Studio

If you have any kind of interest in data science or machine learning, you’ll probably found out that R language is the ultimate survivor. If you are a developer familiar with Visual Studio, you don’t have to adopt for RStudio again. You can code R inside VS!

R Tools for Visual Studio (RTVS) recently released the 0.5 version. One useful feature comes with the new version is SQL integration. With that you can directly import the data loads in your SQL database to a R environment. SQL queries can help you to fetch the data that you want. You can easily play with the data using R then.

First, you have to have Visual Studio 2015 with update 3. (Visual Studio 2015 Comunity edition is freely available to download) Update your VS if you haven’t done it yet and download RTVS 0.5 from here & install it.
https://aka.ms/rtvs-current

In your R project you can add SQL Query item (Right click on solution explorer and “Add new item”) which is created as a *.sql file.

On the top of the panel you can connect the database using “connect” icon. There you should configure the server name, server authentication and the database details.

Inside the .sql file you can execute the typical SQL queries to fetch data from the SQL database. One main advantage of this is, by enabling the execution plan you can analyze and optimize the SQL query you written.

Adding a database connection for the R project –

Go to R tools -> Data -> Add Database Connection
Provide the authentication details of the database that you want to access. Then test the connection using “Test Connection” button. After clicking ‘ok’, you can see the database connection string is automatically generated inside settings.R file. Within the R code you can access for data inside the particular database as shown in the following example code.

The str() output is shown in the R console

The example shows the code used for accessing the data in ‘Iris Data’ table inside ‘DMDatasets’ database placed in the local SQL server. Make sure to install “RODBC” R package to use the database related functions inside R.

#Need RODBC package to extablish the ODBC database iterface
install.packages("RODBC")
require("RODBC")

#Auto-generated Settings.R file should be added as a source
#The connection string contains in this file  
source("Settings.R")
conn <- odbcDriverConnect(connection = dbConnection)

#To get the tables of particualr database
tbls <- sqlTables(conn, tableType = "TABLE")
print(tbls)

#The SQL query is used to fetch data from the table 
sql <- "SELECT * FROM [dbo].[Iris Data]"
df <- sqlQuery(conn, sql)
str(df)
#plotting the dataset
plot(df) 

No need of switching developer environments to handle your coding as well as data analytics tasks. Just keep Visual Studio as your default IDE! 🙂