At the time of writing this articles, the following library versions were used.

1. Node – 8.10
2. oracledb-for-lambda: “^1.9.3-8a

1. Creating bundle

The size of the library oracledb_for_lambda is more than 70 MB which is quite high for you to compile and upload to lambda every single time. Instead of that, You can bundle the lib and add it as a layer. So that we can include the layer directly to Lambda.

Creating this bundle will be our first step. You need to create the below folder structure before adding it to the layer.

First, Create a Node Js project using the below command

npm init

Then Install the oracledb_for_lambda client by executing the below line

npm i oracledb-for-lambda

Now, In the Project folder, Create a folder named nodejs and You need to move the node_modules folder into this nodejs folder. Then, Copy the lib folder inside /node_modules/oracledb-for-lambda and paste it outside in the main project directory.

Finally, you will get a folder structure like the below image. That’s it, Zip the files inside the folder and Upload the Zip to S3.

2. Creating the Layer

As a next step, We are going to create the layer. Once the file is uploaded and available in S3, You can create a layer as described in the below screenshot.

Navigate to Layers and Click Create Layer button.

Then the Layer Configuration form opens. Here Provide the S3 link URL in which the Zip file is uploaded and create the layer.

In the above screenshot, a layer with the name oracle-client-node is created

3. Adding the layer to Lambda

After layer creation, You needs to add it to the Lambda. Open the Lamba function and Click Layers.

In the Layers section, click the Add a layer button and Select the oracle-client-node layer created in the previous step.

Once the layer is added to the Lambda function, You can view it in the Layers section as below.

4. Adding Hostalias

Next, You need to add host aliases pointing a hostname to localhost

But Lambda is something different here. The container (and the resources used by it) that runs our function is managed completely by AWS. It is made live when an event takes place and is turned off if it is not being used. If additional requests are made while the original event is being served, a new container is brought up to serve a request.

So, The hostname may change during every execution. For every execution the ephemeral disk space is available in the form of the /tmp directory. We can only use this space for temporary storage since subsequent invocations will not have access to this.

str_host = os.hostname() + ' localhost\n';
fs.writeFileSync(process.env.HOSTALIASES,str_host , function(err){
    if(err) throw err;
});

Using the above code we are getting the hostname of the execution container (and the resources used by lambda) and add hostaliases in the file /tmp/HOSTALIASES

Also, add the HOSTALIASES key-value in Environment Variables like below

5. Connecting to Oracle DB

Now we can use the below code to connect to Oracle DB from Lambda function.

'use strict';
var os = require('os');
var fs = require('fs');
var oracledb = require('oracledb-for-lambda');
exports.handler = async (event, context) => {
    let str_host = os.hostname() + ' localhost\n';
    fs.writeFileSync(process.env.HOSTALIASES, str_host, function(err) {
        if (err) throw err;
    });
    var connAttr = {
        user: process.env.USERNAME,
        password: process.env.PASSWORD,
        connectString: process.env.CONNECTION_STRING
    };

    const promise = new Promise(function(resolve, reject) {
        oracledb.getConnection(connAttr, function(err, connection) {
            if (err) {
                reject({
                    status: "ERROR"
                });
            }
            resolve({
                status: "SUCCESS"
            });
        });
    });
    return promise;
}

In the above code, the values of USERNAME, PASSWORD, HOSTALIASES, and CONNECTION_STRING can be stored and retrieved from the environment variables.

6. Inserting data into oracle DB

Once the database connection is successful, You can use the below Node Js snippet to insert data to the database.

'use strict';
var os = require('os');
var fs = require('fs');
var oracledb = require('oracledb-for-lambda');

exports.handler = async (event, context) => {
    let str_host = os.hostname() + ' localhost\n';
    fs.writeFileSync(process.env.HOSTALIASES, str_host, function(err) {
        if (err) throw err;
    });

    var connAttr = {
        user: process.env.USERNAME,
        password: process.env.PASSWORD,
        connectString: process.env.CONNECTION_STRING
    };

    const promise = new Promise(async function(resolve, reject) {
        try {
            let connection = await oracledb.getConnection(connAttr); //get connection
            let resultData = await connection.execute(
                "INSERT INTO TABLE_NAME(COLUMN1,COLUMN2) VALUES (:1, :2)", [value1, value2], {
                    autoCommit: true
                },
                function(err, result) {
                    if (err) {
                        resolve({
                            status: "ERROR"
                        })
                    } else {
                        resolve({
                            status: "SUCCESS"
                        })
                    }
                });
        } catch (err) {
            console.log("DB Exception " + err)
            resolve({
                status: "ERROR"
            })
        }
    });
    return promise;
}

7. Fetching the values from oracle DB

Below snippet is used to fetch values from the database.

const promise = new Promise(async function(resolve, reject) {

    try {
        let connection = await oracledb.getConnection(connAttr); //get connection
        let resultData = await connection.execute(
            "SELECT * FROM TABLE_NAME WHERE COLUMN1 = :1)", [value1],
            function(err, result) {
                if (err) {
                    resolve({
                        status: "ERROR"
                    })
                } else {
                    resolve({
                        status: "SUCCESS"
                    })
                }
            });
    } catch (err) {
        console.log("DB Exception " + err)
        resolve({
            status: "ERROR"
        })
    }
});
return promise;
});

Introduction

You may have multiple git accounts, one for official and one for personal, or when you work on cloud like AWS you may have many repositories in different git accounts. At that time, You have to setup multiple usernames in the machine. But it is hard to change the settings every time.

You can solve the problem by setting the alias name for every git accounts. Yeah! Learn more on how to do that.

Generate SSH Key

First, we have to generate SSH key.For that, Open your gitbash terminal and navigate to required path/folder.Type the below command

ssh-keygen

Ssh-keygen is used to create authentication key pairs for SSH.Then provide the preferred file name for storing the key and press enter for remaining options.

$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/c/Users/boopathikumar/.ssh/id_rsa): boopathi_rsa
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in boopathi_rsa.
Your public key has been saved in boopathi_rsa.pub.
The key fingerprint is:
SHA256:7Nr/m0cI+tw+RWUR4JF0slTzGCg78BDw+YhW9nUTN2s boopathikumar@LAPTOP-B9TJ4GJ
The keys randomart image is:
+---[RSA 3072]----+
|      ....  .B*B+|
|       .o.. +.==B|
|        =+ o.o+E.|
|       = +=. .o. |
|      o S.oo o   |
|     . ..   . o  |
|        .o . o   |
|       o  o o..  |
|      . ...o=+   |
+----[SHA256]-----+

Now You can see two keys created as below in the path you have navigated in gitbash.

boopathi_rsa
boopathi_rsa.pub

Adding generated SSH Key in Github

As a next step, You have to add SSH key into your Github account.Login to your Github account, navigate to settings page and click SSH and GPG Keys option and then press New SSH Key button.Provide a proper title and copy paste the content from boopathi_rsa file into the text box and save as shown below

Once key is added, you can view the list of SSH keys in your accounts as below

Adding SSH Key in AWS Code Commit

Now learn how to add the genrated SSH key into your AWS CodeCommit account.

Login to your AWS account and navigate to IAM service and open your IAM user. Under the Security Credentials tab you will find Upload SSH public key button. Click that and copy paste the content from boopathi_rsa file into the text box and save as shown below.

Once key is added you can see the below screen.Copy the SSH key ID for later use in below steps.

Setup configuration file

Till now, We have generated a SSH Key and added it to git. Create a folder in the name of .ssh inside your user folder.

Inside the .ssh folder, create a file in the name config with no extension. Now you will have the folder structure like below.

C:\Users\<your-username>\.ssh\config

The content of the config file should be added in the below format.

Host my.github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile "C:/Users/boopathikumar/.ssh/boopathi_rsa"

Host office.github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile "C:/Users/boopathikumar/.ssh/boopathi_rsa2"

Host my_codecommit
    Hostname git-codecommit.us-east-1.amazonaws.com (only access to repo in us-east-1)
    User  APKAVDUCNF4JYDGHGTNQ (copied SSH key ID)
    PreferredAuthentications publickey
    IdentityFile "C:/Users/CloudKinetics/.ssh/boopathi_rsa"

Host office_codecommit
    Hostname git-codecommit.*.amazonaws.com (to access all region)
    User  XXXXXXXXXXXXXXXXXXXX  
    PreferredAuthentications publickey
    IdentityFile "C:/Users/CloudKinetics/.ssh/boopathi_rsa"

In the above configuration, meaning of each term is shown below

• Host - Provide a alias name for your git account. This will be used instead of hostname.
• Hostname - Actual git account hostname
• User - This is needed only for AWS code commit
• PreferredAuthentications - To authorize with SSH key, Provide the value as publickey
• IdentityFile - Path of you pem key

Now all the configurations are completed. You can clone the repository from any account.

Clone the Repository

Now I am trying to clone the private repository from my personal github account.For that, get the SSH clone URL of the repository as show below

The SSH Clone URL looks like the below

git clone git@github.com:boopathikumar018/sample_repo.git

In that,Change the host name (github.com) to configured Alias host name (my.github.com) now the you URL will be like

git clone git@my.github.com:boopathikumar018/sample_repo.git

Once you execute the clone command, repository will be automatically cloned using the credentials provided under the Alias name in config file

Now I am trying to clone the AWS code commit repository from my AWS account.For that get the SSH Clone URL of the repository as show below

you will get a clone SSH URL of the repository like below

git clone ssh://git-codecommit.us-east-1.amazonaws.com/v1/repos/sample-repo

In this also, Change the host name (git-codecommit.us-east-1.amazonaws.com) to configured Alias name (my_codecommit) now the you URL will be like

git clone ssh://my_codecommit/v1/repos/sample-repo

This will automatically clone the repo using the credentials configured under the Alias name in the config file

Like this, You can configure as many git account as you want and use easily by just changing to Alias name.

Introduction

Now most of the developers using Visual Studio Code for development. And it provides various plugin to make developers code comfortably. I am writing this blog about one of my favourite plugin Remote - SSH which I am using every time to update code in remote server and check logs by running grep command in large log files and export the required contents in separate file and view easily. All these things can be done directly from the Visual Studio Code instead of connecting through a Putty terminal.

Installation & Configure

Install Remote - SSH from the Microsoft marketplace. After successful installation, You can find the "Remote Explorer" icon in the left navigation.

After installing the plugin, we need to create a config file with the list of remote server details which you wish to connect.Create a file in the below mentioned path with name sshConfig (without any extension)

Note : If you didn't have .ssh folder create new folder and enter name as .ssh. and save it

C:\Users\<your-username>\.ssh\sshConfig

Provide the remote server details inside the sshConfig file in the below mentioned format

Host dev
    HostName XXX.XX.XX.XXX
    User ubuntu
    IdentityFile "C:/Users/boopathikumar/.ssh/ubuntu.pem"

Host prod
    HostName XXX.XX.XX.XXX
    User ubuntu
    IdentityFile "C:/Users/boopathikumar/.ssh/ubuntu.pem"

Meaning of the terms used in the above format is explained below

• Host - Provide any name for your remote server for further reference.
• Hostname - Remote server Ip address
• User - Username for login into the server
• IdentityFile - Path of you pem key

Then select the settings icon near SSH TARGETS and add the sshConfig file path which we had created previously.

After that you can see the list of remote servers configured in the sshConfig file inside the Visual Studio Code as shown below

Connect server

To connect to any particular server, Click on the folder icon next to the remote server name as highlighted below.

Then, Select the Operating system of the remote server.

Once the server is connected, You can see the name of the host which you provided on sshConfig file on the bottom left corner.

Click on Open folder button to view the folders in the remote server.Select the folder that you need to view as shown below

After that you can view files under selected remote folder on the explorer as shown below.

Also you can use the integrated terminal to run the commands on connected remote server directly.

Setup "Remote - SSH" and enjoy programming in a remote server directly from Visual Studio Code !!!.