GoLang – Consuming Oracle REST API from an Oracle Cloud Database)

Posted on May 26, 2020 Updated on May 26, 2020

Does anyone write code to access data in a database anymore, and by code I mean SQL?  The answer to this question is ‘It Depends’, just like everything in IT.

Using REST APIs is very common for accessing processing data with a Database. From using an API to retrieve data, to using a slightly different API to insert data, and using other typical REST functions to perform your typical CRUD operations. Using REST APIs allows developers to focus on write efficient applications in a particular application, instead of having to swap between their programming language and SQL. In later cases most developers are not expert SQL developer or know how to work efficiently with the data. Therefore leave the SQL and procedural coding to those who are good at that, and then expose the data and their code via REST APIs. The end result is efficient SQL and Database coding, and efficient application coding. This is a win-win for everyone.

I’ve written before about creating REST APIs in an Oracle Cloud Database (DBaaS and Autonomous). In these writings I’ve shown how to use the in-database machine learning features and to use REST APIs to create an interface to the Machine Learning models. These models can be used to to score new data, making a machine learning prediction. The data being used for the prediction doesn’t have to exist in the database, instead the database is being used as a machine learning scoring engine, accessed using a REST API.

Check out an article I wrote about this and creating a REST API for an in-database machine learning model, for Oracle Magazine.

In that article I showed how easy it was to use the in-database machine model using Python.

Python has a huge fan and user base, but some of the challenges with Python is with performance, as it is an interrupted language. Don’t get be wrong on this, as lots of work has gone into making Python more efficient. But in some scenarios it just isn’t fast enough. In does scenarios people will switch into using other quicker to execute languages such as C, C++, Java and GoLang.

Here is the GoLang code to call the in-database machine learning model and process the returned data.

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
    "os"
)

func main() {
    fmt.Println("---------------------------------------------------")
    fmt.Println("Starting Demo - Calling Oracle in-database ML Model")
    fmt.Println("")

    // Define variables for REST API and parameter for first prediction
    rest_api = "<full REST API>"

    // This wine is Bad
    a_country := "Portugal"
    a_province := "Douro"
    a_variety := "Portuguese Red"
    a_price := "30"

    // call the REST API adding in the parameters
    response, err := http.Get(rest_api +"/"+ a_country +"/"+ a_province +"/"+ a_variety +"/"+ a_price)
    if err != nil {
        // an error has occurred. Exit
        fmt.Printf("The HTTP request failed with error :: %s\n", err)
        os.Exit(1)
    } else {
        // we got data! Now extract it and print to screen
        responseData, _ := ioutil.ReadAll(response.Body)
        fmt.Println(string(responseData))
    }
    response.Body.Close()

    // Lets do call it again with a different set of parameters

    // This wine is Good - same details except the price is different
    a_price := "31"

    // call the REST API adding in the parameters
    response, err := http.Get(rest_api +"/"+ a_country +"/"+ a_province +"/"+ a_variety +"/"+ a_price)
    if err != nil {
        // an error has occurred. Exit
        fmt.Printf("The HTTP request failed with error :: %s\n", err)
        os.Exit(1)
    } else {
        responseData, _ := ioutil.ReadAll(response.Body)
        fmt.Println(string(responseData))
    }
    defer response.Body.Close()

    // All done! 
    fmt.Println("")
    fmt.Println("...Finished Demo ...")
    fmt.Println("---------------------------------------------------")
}