Yet another application to manage feature toggles!

If you want to play around the code for this project, you will require the following:

• .net 5
• Docker
• your favorite IDE (I love vscode, but eh, Rider is still awesome)

This project is split in 2 services :

• the management service
• the evaluation service

As for database/persistence, it uses the awesome EventStore.

The management service is where all feature toggle creation & manipulation are done:

• create a feature
• assign strategies
• publish
• archive

Still to do : a beauuutifull UI for this, coming up, one day ;)

The evaluation service is where you need to call to know if a toggle is on or not. Everytime a call is made to this endpoint we increase a Counter Metric for Prometheus. We don't push our metrics, you have to scrape them.

The current version only enables you to evaluate a single feature at a time: but you can send all the strategy values at once.

A strategy is what drives the evaluation of a feature toggle.

Here is the list of currently supported strategies:

• simple IsOn strategy : only a basic true/false flag;
• IsInList strategy: given a list of items during strategy assignation, the evaluation will validate if the given value is in the list;
• IsBefore: date-time related evaluation, evaluates if the given date is before the one set in the strategy (all checks are exclusive)
• IsAfter: date-time related evaluation, evaluates if the given date is after the one set in the strategy (all checks are exclusive)
• IsGreaterThan: given a number (can be a decimal, double, who cares, ah eh, no exponential format though, give me a little break here....), evaluates if the given value is greater (exclusive values as well: > only)
• IsLowerThan: given a number (same as greater rule), evaluates if the given value is lower (exclusive values as well: < only)

Features can be organised by "Path": you can see paths like a folder or group structure. A feature can have the same name as another one as long as they are not in the same path.

• Relative Path : /features
• Verb: PUT
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "createdBy" : "mommy"
}

Through this endpoint you can only update the name and path if your feature has not been published yet.

• Relative Path : /features
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "newName": "chowmein",
    "newPath" : "cats",
    "updatedBy" : "mommy"
}

Through these endpoints you can assign your strategy if your feature has not been published yet.

You can assign more than one strategy to a feature, they are currently all linked by AND logic.

• Relative Path : /features/strategies/ison
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "assignedBy" : "mommy",
    "isOn": true
}

• Relative Path : /features/strategies/isinlist
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "assignedBy" : "mommy",
    "items": ["cat", "fat"]
}

• Relative Path : /features/strategies/isgreaterthan
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "assignedBy" : "mommy",
    "value": 45678.45678
}

value is a double

• Relative Path : /features/strategies/islowerthan
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "assignedBy" : "mommy",
    "value": 45678.45678
}

value is a double

• Relative Path : /features/strategies/isbefore
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "assignedBy" : "mommy",
    "value": "2020-12-21T21:38:46Z"
}

value is a iso 8601 date format, the date is EXCLUSIVE

• Relative Path : /features/strategies/isafter
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "assignedBy" : "mommy",
    "value": "2020-12-21T21:38:46Z"
}

value is a iso 8601 date format, the date is EXCLUSIVE

Publishing a feature makes it available in the evaluation service and blocks modifications to its definition.

• Relative Path : /features/publish
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "publishedBy" : "mommy"
}

Archiving a feature removes it from the evaluation service.

• Relative Path : /features/archive
• Verb: POST
• Content-Type: application/json
• Body:

{
    "name": "dimsum",
    "path" : "cats",
    "archivedBy" : "mommy"
}

Keeping in mind that one day a UI will be hooked on the management service, we need to be able to list our paths to organise our features:

• Relative Path : /paths
• Verb: GET
• Content-Type: application/json
• Response: a list of paths with their feature counter (currently no filtering on status)

[
    {
        "path": "one",
        "totalFeatures": 1
    },
    {
        "path": "one/level",
        "totalFeatures": 1
    }
]

We can return all features at the root of the path and sub-paths when calling this endpoint (currently no filtering on status):

• Relative Path : /paths/features?path=one
• Verb: GET
• Content-Type: application/json
• Response: a list of features

[
    {
        "feature": "dimsum",
        "path": "one/level",
        "strategyNames": [
            "IsInList"
        ],
        "state": "Published",
        "createdOn": "2020-12-06T23:31:33.155409+00:00",
        "updatedOn": "2020-12-06T23:33:52.0215134+00:00",
        "createdBy": "mommy"
    }
]

• Relative Path : /features?path={{UrlEncodedPath}}&name={{UrlEncodedName}}
• Verb: GET
• Content-Type: application/json
• Response: a list of features

{
    "feature": "dimsum",
    "path": "one/level",
    "strategies": [
        {
            "name": "IsOn",
            "value": "{\"IsOn\":true}"
        },
        {
            "name": "IsInList",
            "value": "{\"ListName\":null,\"Items\":[\"cat\",\"fat\"]}"
        }
    ],
    "state": "Published",
    "createdOn": "2020-12-06T23:31:33.155409+00:00",
    "updatedOn": "2020-12-06T23:33:52.0215134+00:00",
    "createdBy": "moua"
}

There is currently only one endpoint for feature evaluation on the evaluation service:

• Relative Path : /features?path={{UrlEncodedPath}}&name={{UrlEncodedName}}
• Verb: GET
• Content-Type: application/json
• Headers:
  • IsOn : none
  • IsInList:
    • key: add a header per list name specified in your feature. The default is feats.list
    • value: your value
  • IsBefore:
    • key: feats.before
    • value: your date, iso format
  • IsAfter:
    • key: feats.after
    • value: your date, iso format
  • IsGreaterThan:
    • key: feats.greater
    • value: your number (int, negative & floats accepted)
  • IsLowerThan:
    • key: feats.lower
    • value: your number (int, negative & floats accepted)
• Response:

true | false

If your feature has a multitude of strategies : add all the headers you need.

Since we have 2 docker files, there's alittle trik to build them:

docker build -t "feats.evaluations:1.0.0-SNAPSHOT" -f Dockerfile.evaluations .

docker build -t "feats.management:1.0.0-SNAPSHOT" -f Dockerfile.management .

• Navigate to the deploy/local folder
• in a terminal, run docker-compose up