Azure Function to generate a badge for a Visual Studio Team Services release
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README.md

Visual Studio Team Services Release badge generator function

Release badge generator is a simple Azure Function that allows to generate VSTS releases badges on the cheap (unless a huge number of releases are involved the cost of running the service should be zero or close to zero)

A badge is an image (png, gif, svg) that can be embedded in a web page, it shows the release definition name and the release number on a given environment.

badge example

The release badge generator function uses Shields IO service to generate the badges, the badges are then stored on Azure Storage Container where they can be freely accessed over HTTP/HTTPS by anyone.

Badges are generated in (near) real time when the function receives a Release deployment completed event from VSTS.

The service requires NO access to a VSTS account it merely generates the badge when the event is received, it's a totally stateless service it stores no information whatsoever about releases (unless we consider the badges information).

This is a few hours hack, it was no knows issues but it comes with no warranties of reliability. For example it wasn't designed to work around the Shields IO service issues or unavailability there are not retries mechanisms besides the one that is offered by VSTS Service Hook retries mechanisms.

This function is implemented in C# but it could be as easily implemented in JavaScript or Java

VSTS Built in support for badges

Since sprint 131 (March 5) VSTS has built in support for release badges, so this code now serves more as a learning experience than anything else (unless you have extra requirements)

Badge styles

The badge can have three different colors depending on the status (by default only sucessfull deploys generate a badge)

  • succeeded Green
  • Partially suceeded Yellow
  • Failed Red

Requirements

In order to run this services you need two things

This hasn't been tested against Team Foundation Server but it should work.

Running costs

The costs to run the service depends on the type of hosting you have chosen for the function, the amount of storage (and storage redundancy) used and the number of times the badges are served.

See

For example you can host the function on a web application you already have (something you are already paying), create a new web app, or choosing a consumption plan in which you only pay for usage.

The consumption plan has a very generous monthly free grant (although it uses a storage account which is not free) which for badge generation purposes will never be hit unless you have a huge number of releases per month (by huge I mean over several hundred thousands of badge generations).

The cost of running this service will be hardly over a few cents per month if using a consumption plan (including storage)

Installation

You can either manually provision the Azure resources neeeded to run the generator. The generator needs the following resources

  • A Function App to host the function, this may also create
    • A storage account (you can use an existing one)
    • A hosting plan (you can use an existing one)
  • A storage account to hold the badges.
    • This storage needs to have a storage container named badges with a blob (anonymous read access for blobs only access policy.

badges container shared policies

The function needs to have a setting called AzureWebJobsBadgesBlob with a connection string to the badges storage account. This can be done in either the Application settings on the Azure portal for example or on the host.json function file. (more on this later)

function application settings

Provisioning Azure Resources

You don't need to manually provision Azure resources, you just need to run the Deploy-AzureResourceGroup.ps1 PowerShell file located on the provision folder to create all necessary Azure resources and create the badges container on the badges storage account with the appropriate permissions.

This script does two things

  • Use an ARM template to either provision a dedicated function app (Azure App Service plan) or a consumption function (pay per use) app (this step is optional)
  • Create a storage container in the badges storage account and sets the permission so anyone can read the badges.

Learn more about automating the deploy of an Azure function

Make sure you are logged in to Azure (for example using Login-AzureRmAccount) before executing the provided PowerShell script.

When running the Deploy-AzureResourceGroup.ps1 passing a value on HostType parameter will trigger the creation of the Azure resources. This parameter has two possible values

  • Dedicated to host the function in a dedicated web app
  • Consumption to host the function on a consumption plan.

If you skip the HostType parameter, no resources will be create. Only the storage container will be created.

This affects the ammount you may pay for using the Function. Learn more about the consequences of different hostng plans in Azure Functions hosting plans comparison

The following parameters can be used to parameterize the resources that will be created:

  • ResourceGroupName The name of the resource group
  • ResourceGroupLocation The data center where the resources will be created. You can get the list of locations by running the PowerShell command
Get-AzureRmLocation | select location

or the Azure Command Line Interface command

az account list-locations --output table
  • StorageAccountType The type of storage to be used to store the functions. With possible values
    • Standard_LRS
    • Standard_GRS
    • Standard_RAGRS

    This affects the price you will pay for storage and the availability/redundancy of data

  • BadgeStorageAccountType The type of storage to be used to store badges (sames value set as StorageAccountType)
  • BadgesStorageAccountName The name of the badges storage account, this name must be unique (across Azure) and will be used on the URL used to serve the badges. Eg if you choose mybadges as the account name, the badges will be accesible on _ https://mybadges.blob.core.windows.net/badges_
  • HostingPlanName (optional) The name of the hosting plan.
  • ApplicationInsightsLocation Location of the Application Insights resource location. Keep in mind Application Insights is only available in a few regions (East Us, West US2, South Central US, North Europe, West Europe, Southeast Asia). A Basic will be setup (basic has no costs unless the 1 GB per month data cap is exceeded)
  • NoAnonymousAccess Don't set badges storage container access level as anonynmous (only people with a token will be able to see the badges)
  • ValidateOnly Only validates the changes, doesn't perform any.

If you are provisiniong a dedicated hosting ( HostType with value Dedicated) there are two additional (optional parameters)

  • SKU Hosting plan size, this affects the cost of running the service. Possible values (default value free)
    • Free
    • Shared
    • Basic
    • Standard
  • WorkerSize Scale the number of instances (default value 1)

Learn more about Azure Resource Manager

The ARM template also configures the function application setting AzureWebJobsBadgesBlob with the connection string for the BadgesStorageAccountName

To provision a consuption function app you can use

 .\Deploy-AzureResourceGroup.ps1  -ResourceGroupName GenerateRMBadge -ResourceGroupLocation "South Central US" -StorageAccountType Standard_LRS -BadgeStorageAccountType Standard_LRS -B
adgesStorageAccountName "tspbadgesconsumption"  -AppName GenerateRMBadge -HostType Consumption

Deploying

After the Azure Function has been provisioned in Azure you can deploy the code using Visual Studio Deploy

right click publish

right click publish

But you should automate build and deployment using your favorite tool of choice and don't deploy it directly from an IDE.

Learn how you can setup Continuous deployment for Azure Functions using Azure built in mechanism or using VSTS

Configuring VSTS Web Hook

In order to generate badges we need to configure one (or more) VSTS web hooks. The first thing we need to do is fetch the URL for the GenerateBadge Function (for example you can get it on Azure portal)

get url for function GenerateBadge

Once we have the URL, configure a Service hook, on the VSTS team project admin page)

VSTS service hooks

The Service hook needs to be configured with the following settings

  • Service Web Hooks
  • Trigger Release deployment completed
  • URL The URL of the GenerateBadge Azure Function
  • Resource Details to send All
  • Messages to send None (in fact this value doesn't matter, but we might as well save some bandwitdh)
  • Detailed messages to send None (in fact this value doesn't matter, but we might as well save some bandwitdh)

Parameterizing badges generation

There are three ways to parameterize badge generations, the first one is via HTTP headers. You can configure HTTP headers on the service hook itself.

configuring HTTP headers

This allows to have specific parameters for different service hooks, if no parameter is overriden via an HTTP header than the generator uses the parameter defined at the function level (host.json) or via Application settings. If no parameter is defined, then the default value is used.

This allows to have parameters specific to service hooks and general parameters at the function level (HTTP headers override function settings)

Parameters

Parameter Description Application Setting Name HTTP Header Default Value
Enable All Status (true or false) Generate a badge for all status. By default only sucessfull deploys generate a badge. EnableForAllStatus X-EnableForAllStatus false
Badge Style Define the style of the badge. Styles defined by Shields IO (plastic,flat,flat-squared) Style X-Style
Badge File Type The type of file to generate (png,gif,svg,...) see Shields IO docs for complete list FileType X-FileType png
Release Definition friendly name Override the definition name (for the badge filename). This only makes sense if you have one service hook per release definition. X-ReleaseDefinitionFileFriendlyName false
Cache Max Age (minutes) Sets the badge max age cache on the client browser. The bigger the cache duration, the less costs you incur in traffice (at the cost of the possibility of a repeat user seeing an outdated badge). Badges sizes are small, unless you have tens of millions accesses there should be no extra cost in data transfers. You should adjust this to the expected frequency of releases. MaxAge X-MaxAge 15 minutes
Use release name (true or false) Use relase name as part of the filename instead of the release id. While the release name will make it easier to reference badges it also means you may have to rewrite references to badges if the release definition name is changed. UseReleaseName X-UseReleaseName false

Accessing badges

Once a badge is generated it is stored in the badges storage container with the following structure

badges/{team project identifier}/{release identifier or name}-{environment name}.{file type extension}

  • {team project identifier} To get the team projet identifier you can use the APP enter following URL in a browser https://{instance}/DefaultCollection/_apis/projects/{project} (whereas project is the project name). Get the id from the returned message. (it's a GUID)
  • release identifier or name This value depends on the configuration. If
    • Release Definition friendly name if defined this value will be used.
    • Use release name is enabled then the release name will be used
    • Otherwise the release identifier is used. To get the release identifier you can the API to get the list of release definitions by entering the url in the browser https://{account}.vsrm.visualstudio.com/{project}/_apis/release/definitions and get the release id (a numeric value) for the release definition you want to get the badge.

After generated the badge is available via HTTP/HTTPS via the url http://{storage accounturl}/badges/{team project identifier}/{release identifier or name}-{environment name}.{file type extension}

Example

https://tspbadgesconsumption.blob.core.windows.net/badges/4ffd7d95-462b-4473-85cc-f4a987227d72/2-Production.png

All team project are stored in a single folder so it's easy to delete them.

License

All code is coyrighted by Tiago Pascoal and licensed under a MIT license