Replace user content in Logic App workflows with the Regex Translator

motivation

At the time of writing, there is no built-in Logic App functionality available to run regular expression replacements without using inline code. The Invictus Regex Translation Framework component was created to fill this missing gap, by providing a HTTP-endpoint to run regular expression replacements. Available translations are stored in an Azure Table Storage.

Regex translate user content

The Regex Translation component has a single endpoint available: /api/RegexTranslation. Given an user content and matched stored (Azure Table Storage, default: RegexTranslator table) regex translation, the endpoint responds with the translated content.

The following request body properties must be supplied:

JSON property	Required	Description
Content	yes	User content that should translated.
MatchKey	yes	Set of 'keys' that translates to Azure Table Storage partition keys.

Full request example

// POST /api/RegexTranslation
{
  "Content": "The provided host name 'website.com' could not be resolved",
  "MatchKey": ["OrderService", "InvoiceService"]
}

Full response example

// Found stored translation:
// 200 OK <- /api/RegexTranslation
{
  "Content": "System could not reach endpoint 'website.com' as it is not available, please contact John to follow-up.",
  "IsTranslated": true,
  "RowKey": "2f71ec69-1fff-4b80-9ae1-947a58e4a039"
}

// Did not found stored translation:
// 200 OK <- /api/RegexTranslation
{
  "Content": "The provided host name 'website.com' could not be resolved",
  "IsTranslated": false,
  "RowKey": ""
}

Stored regex translations

Regex translations should be stored in an Azure Table Storage table called RegexTranslator (created automatically by Invictus). Each stored entity should have following custom properties:

Custom entity property name	Description
MatchPattern	The regular expression to match the incoming user Content. It uses named groups to cut certain information from the content.
OutputPattern	The outgoing text, containing possible {group-name} occurrences to paste the subtracted information.

Full translation example

Entity property name	Value
RowKey	2f71ec69-1fff-4b80-9ae1-947a58e4a039
PartitionKey	OrderService
MatchPattern	"The provided host name '(?<url>[^]*)' could not be resolved."
OutputPattern	"System could not reach endpoint '{url}' as it is not available, please contact John to follow-up."

Translation happens with the following:

• Multiple pastes: the subtracted information from named groups can be pasted more than once.
• Single match: the user Content can only be matched to a single stored translation - the first match will be picked.
• No pastes: the OutputPattern does not necessarily have to contain {group-name} occurrences, it can only contain text.

Customization

Related Bicep parameters

The following Bicep parameters control the inner workings of the Regex Translator component. See the release pipeline step of the deployment of the Invictus Framework to learn more.

Bicep parameter	Default	Description
storageAccountName	invictus{resourcePrefix}store	The name of the Azure Storage Account (used by other Framework components as well) where the RegexTranslator Azure Table Storage table will be located.
regexTranslatorScaling	{ cpuResources: '0.5', memoryResources: '1.0Gi', scaleMaxReplicas: 1, scaleMinReplicas: 0, concurrentRequests: 10 }	The Container App options to control scaling. See scaling rules in Azure Container Apps.
regexTranslatorFunctionName	inv-${resourcePrefix}-regextranslator	The name of the Azure Container App to be created for the Regex Translator component.