Enabling Source Control for locally stored code using Git, Visual Studio Code and Sourcetree

Introduction

Coming from a system administration background, I am used to writing scripts to get mundane tasks done. Whenever I saw repeatable tasks, I saw an opportunity to script them, and pass them onto a junior to do ūüėČ

However, writing scripts brings about its own challenges.

Ok, time to fess up ūüėČ Hands up those that have modified a script, only to realise that the modifications broke it! To make matters worse, you forgot to take a copy of the original!

Don’t worry, I have been in that boat, and can remember the countless hours I spent, getting the script back to what it was (mind you, I am not talking about a formal business change here, which is governed by strict change control, but about personal scripts, that you have created to make your daily tasks easier)

To make a copy of a script, I would normally suffix the file with the current time and date. This provided me with a timestamp of when I changed the file and a way of reverting my changes. However, there were instances when I was making backups of the modified script because I had tested a modification and it worked, however I didn’t want to risk breaking it when further modifying the file. Guess what, these are the times when I found I made the worst mistakes! I used to get so engrossed with my modifications that I would forget to make a backup of the changes and end up with an unworkable script. The only version to revert to was the original, which meant all my hard work went to waste!

This is why I started my search for a better change tracking system. One that will show me the changes I had made, and which will allow me to easily revert to a previous version.

Guess what! I think I just found this golden goose and it is truly amazing!

In this blog I will show you how you can use Git, an open source version control system,  to track changes to scripts stored locally on your computer. The main use of Git is for source control of files that a team contributes to. In these situations, a Git Server is used to store the repository.

Please ensure that the local folder you are tracking for source control is backed up either to the cloud or to an external hard disk.

For editing our code/script, we will use Microsoft’s Visual Studio Code, a free IDE that has Git support in-built. We will also use Sourcetree, Atlassian’s free Git client.

 

Introducing Git

Git is an awesome opensource distributed version control system. When working in a team, it allows you to have your files centrally managed, and at the same time, allowing multiple people to work on them. Team members can pull the repository to their local computer. They can also branch a part of the repository, update the files in that part and then merge them with the master. If there are no conflicts, Git will update the files in its repository. However, if there are conflicts, Git will inform that team member, showing them the conflicts. The team member then can either resolve the conflicts and then re-merge or discard their changes altogether.

If you want to read more on git, check out https://git-scm.com

To host the repositories for your team, two commonly used solutions are a Git Server or Visual Studio Teams Server. You can also use Github, however, your repositories will be public, unless you sign up for a paid account.

For personal use, you can store your git repositories in a local directory that is backed up to the cloud. For my personal projects, I use a Dropbox synchronised folder.

To use Git, you need to use a Git client. If you have a MacBook, a git client comes built-in. For windows, there are lots of clients available, however in my view, Sourcetree is one of the best (more about this abit later).

For MacBook users, below are some basic commands you can use from a terminal session

#change to directory where you will store your repository
cd /Users/tomj/Documents/git-repo/personalproject

#create a git repo in this folder
git init

#you can copy files into this folder
#to get git to start tracking the changes in the newly added files use the following command
git add .

 

As mentioned above, https://git-scm.com is an awesome site to learn more about Git.

You can also check out this page https://www.atlassian.com/git/tutorials/atlassian-git-cheatsheet for some quick git commands.

Using Sourcetree

For those that prefer a GUI client, I found that Sourcetree, from Atlassian, is an awesome Git client.

It gives you all the features of a good Git client plus it also shows you the history of all the changes made to the repository.

For this blog, I will be using Sourcetree to create and manage the Git repository.

So head over to https://www.sourcetreeapp.com to download and then install the client.

After installing Sourcetree, you will be prompted for a login account. Follow the links provided in the Sourcetree app to create a free Bitbucket account and then login.

Ok, lets begin.

Create a new repository

A repository is essentially a collection of files (or file) that we will track for changes. You can think of it as a directory.

To create a new repository, open Sourcetree.

From the menu, click on File and then click New. You will get the following screen.

Sourcetree_newRepo

Next, click on New and then click on Create Local Repository.

In the next window, for Destination Path, select the folder that will contain the scripts that you want to monitor for source control.

For  Name leave it to the default (name of the folder). Ensure the Type is Git and then click Create.

Guess what, thats all it takes to create a local repository! Simple ?

Once the repository is created, you will see a screen similar to the one shown below (my repository is called temp)

Sourcetree_newRepoCreated.

Double click on the newly created repository (as shown above). This will show the dashboard where everything happens ūüėČ

Sourcetree_RepoDashboard

 

To see all the changes that have been made to the repository, click on History in the above screen.

Visual Studio Code

Ok, so we have created our repository and it is being monitored for changes. Now, we can start coding.

As mentioned above, we will be using Visual Studio Code, a free IDE from Microsoft. If you haven’t got it already, download it from¬†https://code.visualstudio.com

Once installed, open Visual Studio Code.

From the menu, click on File and then click on  Open.  Next, choose the folder that you created the repository for above and then click on Open.

You will now see the folder structure, with all the files inside it in the left pane.

You can open any of the existing files or create new ones. For new ones, ensure you save them in the repository’s folder.

As soon as you save the file, you will notice the¬†Source Control icon shows the number of changes that are currently ready to be staged (Source Control section is denoted by the “stethoscope” icon – ok it’s not really that but it surely looks like it ūüėČ )

VSC_SourceControl_Update

Now, one thing to note about Source Control via Git is that, you have to stage your changes. When you stage your changes, those changes will be written to the Git repository when you click Commit.

Click into the Source Control section and then under Changes click the + for each of the files, to stage the change.

VSC_SourceControl_Update_Changes

To commit the changes, enter a short description of what the changes were and then click on the tick at the top.

VSC_SourceControl_Update_Changes_Commit

That’s it. Your changes has now been successfully committed to the Git repository.

To view a history of all the changes that have been done to your repository, open Sourcetree and then click on History.

Notice the description column. This contains the comments you wrote when committing your staged changes. This provides a quick reminder of what the changes were. To drill down deeper into the changes, check the pane at the bottom right. Here, you will see the actual changes that were made (green denotes additions and red denotes deletion of characters). If there are multiple people committing to the same repo (as would be the case in a team), the names of each person will be shown beside each line in the History section.

Sourcetree_ViewHistory

Now, lets say that after you did your commit, you realised that you didn’t want that change, and in-fact you prefer what the file was before the commit. All you need to do is go into¬†Sourcetree, in the¬†History section, find the change and then right click on it and then click on¬†Reverse commit. This reverses the commit and changes the file to what it previously was. If after that, you want to get back the change? Well, you can reverse the¬†reverse commit ūüėČ (this is so much better than my method of copying the last suffixed version to the current version)

Soucetree_ReverseCommit

Closing Remarks

I am absolutely loving Git. It is an awesome tool and I would highly recommend it to each and everyone. For me personally, it helps in controlling the various changes I make to my code, with easy auditability and view of the changes I make between versions.

For teams, Git provides even more benefits. Using a central server (Git Server or Visual Studio Team Services) to host the Git repositories, the whole team can work on the files without blocking each other. The files will be stored centrally (actually with Git, when you pull a repo, you download the full repo to your local computer. If you merge your changes, the files are merged to the copy on the server). The changes to the files are easily trackable and there is an easy way to revert to a previous version should issues arise due to modifications.

I hope you embrace Git as I have and use it to track all your code changes.

Till the next time, Enjoy ūüėČ

 

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Ok Google Email me the status of all vms – Part 2

In my last blog, we configured the backend systems necessary for accomplishing the task of asking Google Home “OK Google Email me the status of all vms” and it sending us an email to that effect. If you haven’t finished doing that, please refer back to my last blog¬†and get that done¬†before continuing.

In this blog, we will configure Google Home.

Google Home uses Google Assistant to do all the smarts. You will be amazed at all the tasks that Google Home can do out of the box.

For our purposes, we will be using the platform IF This Then That or IFTTT for short. IFTTT is a very powerful platform as it lets you create actions based on triggers. This combination of triggers and actions is called a recipe.

Ok, lets dig in and create our IFTTT recipe to accomplish our task

1.1 ¬† Go to¬†https://ifttt.com/¬†and create an account (if you don’t already have one)

1.2   Login to IFTTT and click on My Applets menu from the top

IFTTT_MyApplets_Menu

1.3   Next, click on New Applet (top right hand corner)

1.4   A new recipe template will be displayed. Click on the blue + this choose a service

IFTTT_Reicipe_Step1

1.5 ¬† Under¬†Choose a Service¬†type “Google Assistant”

IFTTT_ChooseService

1.6   In the results Google Assistant will be displayed. Click on it

1.7 ¬† If you haven’t already connected IFTTT with Google Assistant, you will be asked to do so. When prompted, login with the Google account that is associated with your Google Home and then approve IFTTT to access it.

IFTTT_ConnectGA

1.8   The next step is to choose a trigger. Click on Say a simple phrase

IFTTT_ChooseTrigger

1.9   Now we will put in the phrases that Google Home should trigger on.

IFTTT_CompleteTrigger

For

  • What do you want to say? enter “email me the status of all vms
  • What do you want the Assistant to say in response? enter “no worries, I will send you the email right away

All the other sections are optional, however you can fill them if you prefer to do so

Click Create trigger

1.10   You will be returned to the recipe editor. To choose the action service, click on + that

IFTTT_That

1.11  Under Choose action service, type webhooks. From the results, click on Webhooks

IFTTT_ActionService

1.12   Then for Choose action click on Make a web request

IFTTT_Action_Choose

1.13   Next the Complete action fields screen is shown.

For

  • URL – paste the webhook url of the runbook that you had copied in the previous blog
  • Method – change this to¬†POST
  • Content Type – change this to¬†application/json

IFTTT_CompleteActionFields

Click Create action

1.13   In the next screen, click Finish

IFTTT_Review

 

Woo hoo. Everything is now complete. Lets do some testing.

Go to your Google Home and say “email me the status of all vms”. Google Home should reply by saying “no worries. I will send you the email right away”.

I have noticed some delays in receiving the email, however the most I have had to wait for is 5 minutes. If this is unacceptable, in the runbook script, modify the Send-MailMessage command by adding the parameter -Priority High. This sends all emails with high priority, which should make things faster. Also, the runbook is currently running in Azure. Better performance might be achieved by using Hybrid Runbook Workers

To monitor the status of the automation jobs, or to access their logs, in the Azure Automation Account, click on Jobs in the left hand side menu. Clicking on any one of the jobs shown will provide more information about that particular job. This can be helpful during troubleshooting.

Automation_JobsLog

There you go. All done. I hope you enjoy this additional task you can now do with your Google Home.

If you don’t own a Google Home yet, you can do the above automation using Google Assistant as well.

Ok Google Email me the status of all vms – Part 1

Technology is evolving at a breathtaking pace. For instance, the phone in your pocket has more grunt than the desktop computers of 10 years ago!

One of the upcoming areas in Computing Science is Artificial Intelligence. What seemed science fiction in the days of Isaac Asimov, when he penned I, Robot seems closer to reality now.

Lately the market is popping up with virtual assistants from the likes of Apple, Amazon and Google. These are “bots” that use Artificial Intelligence to help us with our daily lives, from telling us about the weather, to reminding us about our shopping lists or letting us know when our next train will be arriving. I still remember my first virtual assistant¬†Prody Parrot, which hardly did much when you compare it to Siri, Alexa or Google Assistant.

I decided to test drive one of these virtual assistants, and so purchased a Google Home. First impressions, it is an awesome device with a lot of good things going for it. If only it came with a rechargeable battery instead of a wall charger, it would have been even more awesome. Well maybe in the next version (Google here’s a tip for your next version ūüėČ )

Having played with Google Home for a bit, I decided to look at ways of integrating it with Azure, and I was pleasantly surprised.

In this two-part blog, I will show you how you can use Google Home to send an email with the status of all your Azure virtual machines. This functionality can be extended to stop or start all virtual machines, however I would caution against NOT doing this in your production environment, incase you turn off some machine that is running critical workloads.

In this first blog post, we will setup the backend systems to achieve the tasks and in the next blog post, we will connect it to Google Home.

The diagram below shows how we will achieve what we have set out to do.

Google Home Workflow

Below is a list of tasks that will happen

  1. Google Home will trigger when we say “Ok Google email me the status of all vms”
  2. As Google Home uses Google Assistant, it will pass the request to the IFTTT service
  3. IFTTT will then trigger the webhooks service to call a webhook url attached to an Azure Automation Runbook
  4. A job for the specified runbook will then be queued up in Azure Automation.
  5. The runbook job will then run, and obtain a status of all vms.
  6. The output will be emailed to the designated recipient

Ok, enough talking ūüėČ lets start cracking.

1. Create an Azure AD Service Principal Account

In order to run our Azure Automation runbook, we need to create a security object for it to run under. This security object provides permissions to access the azure resources. For our purposes, we will be using a service principal account.

Assuming you have already installed the Azure PowerShell module, run the following in a PowerShell session to login to Azure

Import-Module AzureRm
Login-AzureRmAccount

Next, to create an Azure AD Application, run the following command

$adApp = New-AzureRmADApplication -DisplayName "DisplayName" -HomePage "HomePage" -IdentifierUris "http://IdentifierUri" -Password "Password"

where

DisplayName is the display name for your AD Application eg “Google Home Automation”

HomePage is the home page for your application eg http://googlehome (or you can ignore the -HomePage parameter as it is optional)

IdentifierUri is the URI that identifies the application eg http://googleHomeAutomation

Password is the password you will give the service principal account

Now, lets create the service principle for the Azure AD Application

New-AzureRmADServicePrincipal -ApplicationId $adApp.ApplicationId

Next, we will give the service principal account read access to the Azure tenant. If you need something more restrictive, please find the appropriate role from https://docs.microsoft.com/en-gb/azure/active-directory/role-based-access-built-in-roles

New-AzureRmRoleAssignment -RoleDefinitionName Reader -ServicePrincipalName $adApp.ApplicationId

Great, the service principal account is now ready. The username for your service principal is actually the ApplicationId suffixed by your Azure AD domain name. To get the Application ID run the following by providing the identifierUri that was supplied when creating it above

Get-AzureRmADApplication -IdentifierUri {identifierUri}

Just to be pedantic, lets check to ensure we can login to Azure using the newly created service principal account and the password. To test, run the following commands (when prompted, supply the username for the service principal account and the password that was set when it was created above)

$cred = Get-Credential 
Login-AzureRmAccount -Credential $cred -ServicePrincipal -TenantId {TenantId}

where Tenantid is your Azure Tenant’s ID

If everything was setup properly, you should now be logged in using the service principal account.

2. Create an Azure Automation Account

Next, we need an Azure Automation account.

2.1   Login to the Azure Portal and then click New

AzureMarketPlace_New

2.2   Then type Automation and click search. From the results click the following.

AzureMarketPlace_ResultsAutomation

2.3   In the next screen, click Create

2.4   Next, fill in the appropriate details and click Create

AutomationAccount_Details

3. Create a SendGrid Account

Unfortunately Azure doesn’t provide relay servers that can be used by scripts to email out. Instead you have to either use EOP (Exchange Online Protection) servers or SendGrid to achieve this. SendGrid is an Email Delivery Service that Azure provides, and you need to create an account to use it. For our purposes, we will use the free tier, which allows the delivery of 2500 emails per month, which is plenty for us.

3.1   In the Azure Portal, click New

AzureMarketPlace_New

3.2   Then search for SendGrid in the marketplace and click on the following result. Next click Create

AzureMarketPlace_ResultsSendGrid

3.3   In the next screen, for the pricing tier, select the free tier and then fill in the required details and click Create.

SendGridAccount_Details

4. Configure the Automation Account

Inside the Automation Account, we will be creating a Runbook that will contain our PowerShell script that will do all the work. The script will be using the Service Principal and SendGrid accounts. To ensure we don’t expose their credentials inside the PowerShell script, we will store them in the Automation Account under Credentials, and then access them from inside our PowerShell script.

4.1   Go into the Automation Account that you had created.

4.2   Under Shared Resource click Credentials

AutomationAccount_Credentials

4.3    Click on Add a credential and then fill in the details for the Service Principal account. Then click Create

Credentials_Details

4.4   Repeat step 4.3 above to add the SendGrid account

4.5   Now that the Credentials have been stored, under Process Automation click Runbooks

Automation_Runbooks

Then click Add a runbook and in the next screen click Create a new runbook

4.6   Give the runbook an appropriate name. Change the Runbook Type to PowerShell. Click Create

Runbook_Details

4.7   Once the Runbook has been created, paste the following script inside it, click on Save and then click on Publish

Import-Module Azure
$cred = Get-AutomationPSCredential -Name 'Service Principal account'
$mailerCred = Get-AutomationPSCredential -Name 'SendGrid account'

Login-AzureRmAccount -Credential $cred -ServicePrincipal -TenantID {tenantId}

$outputFile = $env:TEMP+ "\AzureVmStatus.html"
$vmarray = @()

#Get a list of all vms 
Write-Output "Getting a list of all VMs"
$vms = Get-AzureRmVM
$total_vms = $vms.count
Write-Output "Done. VMs Found $total_vms"

$index = 0
# Add info about VM's to the array
foreach ($vm in $vms){ 
 $index++
 Write-Output "Processing VM $index/$total_vms"
 # Get VM Status
 $vmstatus = Get-AzurermVM -Name $vm.Name -ResourceGroupName $vm.ResourceGroupName -Status

# Add values to the array:
 $vmarray += New-Object PSObject -Property ([ordered]@{
 ResourceGroupName=$vm.ResourceGroupName
 Name=$vm.Name
 OSType=$vm.StorageProfile.OSDisk.OSType
 PowerState=(get-culture).TextInfo.ToTitleCase(($vmstatus.statuses)[1].code.split("/")[1])
 })
}
$vmarray | Sort-Object PowerState,OSType -Desc

Write-Output "Converting Output to HTML" 
$vmarray | Sort-Object PowerState,OSType -Desc | ConvertTo-Html | Out-File $outputFile
Write-Output "Converted"

$fromAddr = "senderEmailAddress"
$toAddr = "recipientEmailAddress"
$subject = "Azure VM Status as at " + (Get-Date).toString()
$smtpServer = "smtp.sendgrid.net"

Write-Output "Sending Email to $toAddr using server $smtpServer"
Send-MailMessage -Credential $mailerCred -From $fromAddr -To $toAddr -Subject $subject -Attachments $outputFile -SmtpServer $smtpServer -UseSsl
Write-Output "Email Sent"

where

  • ‘Service Principal Account’ and ‘SendGrid Account’ are the names of the credentials that were created in the Automation Account (include the ‘ ‘ around the name)
  • senderEmailAddress is the email address that the email will show it came from. Keep the domain of the email address same as your Azure domain
  • recipientEmailAddress is the email address of the recipient who will receive the list of vms

4.8   Next, we will create a Webhook. A webhook is a special URL that will allow us to execute the above script without logging into the Azure Portal. Treat the webhook URL like a password since whoever possesses the webhook can execute the runbook without needing to provide any credentials.

Open the runbook that was just created and from the top menu click on Webhook

Webhook_menu

4.9   In the next screen click Create new webhook

4.10  A security message will be displayed informing that once the webhook has been created, the URL will not be shown anywhere in the Azure Portal. IT IS EXTREMELY IMPORTANT THAT YOU COPY THE WEBHOOK URL BEFORE PRESSING THE OK BUTTON.

Enter a name for the webhook and when you want the webhook to expire. Copy the webhook URL and paste it somewhere safe. Then click OK.

Once the webhook has expired, you can’t use it to trigger the runbook, however before it expires, you can change the expiry date. For security reasons, it is recommended that you don’t keep the webhook alive for a long period of time.

Webhook_details

Thats it folks! The stage has been set and we have successfully configured the backend systems to handle our task. Give yourselves a big pat on the back.

Follow me to the next blog, where we will use the above with IFTTT, to bring it all together so that when we say “OK Google, email me the status of all vms”, an email is sent out to us with the status of all the vms ūüėČ

I will see you in Part 2 of this blog. Ciao ūüėČ

Script to shutdown servers

I run a lot of Microsoft virtual machines in Azure and also locally on my MacBook Pro. These are my lab machines, which I use for testing.

One of the issues with having many virtual machines is orderly shutting them down. It can be a pain to go through each of them and shutting them down.

To circumvent this, I wrote a small PowerShell script, which does it all for me ūüôā

The script requires the following

$serverlist contains the hostnames of the servers that you want to shutdown (in the order they need to be shutdown)

$server_domainname this is the domain name that the servers are part of.

servername and and server_domainname is used to figure out the server fqdn, which is then used to shutdown that server.

Run the script from a computer that can connect to the servers. Ensure you are logged on as an account that has permissions to shutdown the servers.

The script will go through the list of servers contained in $serverlist and check if they are online. If they are online, then it will try to shut them down.

Do note that these servers will be forced to shutdown, so anything open on those servers will be lost, if not saved.

Once all the online servers have been shutdown, you will be asked if you want to shutdown the computer you are running the script from. You can press Enter to continue or CTRL+C to skip shutting down the computer you are logged on.

Hope this script comes in handy to others

Re-execute the UserData script in an AWS Windows Instance

Bootstrapping is an awesome way of customising your instances in AWS (similar capability exists in Azure).

To enable bootstrapping, while configuring the launch instance, in Step 3: Configure Instance Details scroll down to the bottom and then expand Advanced Details.

You will notice a User data text box. This is where you can provide your bootstrap script. The script will be run when your instance is first launched.

AWS_BootstrapScript

I went ahead and entered my script in the text box and proceeded to complete my instance configuration. Once my instance was running, I initiated a Remote Desktop connection to it, to confirm that my script had run. Unfortunately, I couldn’t see any customisations (which meant my script didn’t run)

Thinking that the instance had not been able to access the user data, I opened up Internet Explorer and then browsed to the following url (this is an internal url that can be used to access the user-data)

http://169.254.169.254/latest/user-data/

I was able to successfully access the user-data, which meant that there were no issues with that. ¬†However when checking the content, I noticed a typo! Aha, that was the reason why my customisations didn’t happen.

Unfortunately, according to AWS, user-data is only executed during launch (for those that would like to read, here¬†is the official AWS documentation). To get the fixed bootstrap script to run, I would have to terminate my instance and launch a new one with the corrected script (I tried re-booting my windows instance after correcting my typo, however it didn’t run).

I wasn’t very happy on terminating my current instance and then launching a new one, since for those that might not be aware, AWS EC2 compute charges are rounded up to the next hour. Which means that if I terminated my current instance and launched a new one, I would be charged for 2 x 1hour sessions instead of just 1 x 1 hour!

So I set about trying to find another solution. And guess what, I did find it ūüôā

Reading through the volumes of documentation on AWS, I found that when Windows Instances¬†are provisioned, the service that does the customisations using user-data is called¬†EC2Config. This service runs the initial startup tasks when the instance is first started and then disables them. HOWEVER, there is a way to re-enable the startup tasks later on ūüôā Here is the document that gives more information on¬†EC2Config.

The Amazon Windows AMIs include a utility called EC2ConfigService Settings. This allows you to configure EC2Config to execute the user-data on next service startup. The utility can be found under All Programs (or you can search for it).

AWS_EC2ConfigSettings_AllApps

AWS_EC2ConfigSettings_Search

Once Open, under General you will see the following option

Enable UserData execution for next service start (automatically enabled at Sysprep) eg. or <powershell></powershell>

AWS_EC2ConfigSettings

Tick this option and then press OK. Then restart your Windows Instance.

After your Windows Instance restarts, EC2Config will execute the userData (bootstrap script) and then it will automatically remove the tick from the above option so that the userData is not executed on subsequent restarts (or service starts)

There you go. A simple way to re-run your bootstrap scripts on an AWS Windows Instance without having to terminate the current instance and launching a new one.

There are other options available in the EC2ConfigService Settings that you can explore as well ūüôā