Percentage rollouts

A rule or the default rule can serve a percentage rollout instead of one variation: each variation gets a weight, and each context gets one variation, the same one every time.

Weights

Weights are integers in thousandths of a percent and add up to exactly 100000: 25000 is 25%, 33333 is 33.333%. The console’s slider works in whole percents.

{
  "rollout": {
    "bucketBy": "targetingKey",
    "weights": [
      { "variation": "true", "weight": 25000 },
      { "variation": "false", "weight": 75000 }
    ]
  }
}

Bucketing

A context’s bucket comes from the flag’s key and the bucketBy attribute, targetingKey unless you name another. So:

• The same context gets the same variation on every evaluation and in every provider.
• Bucketing by another attribute (companyId) rolls out by account: everyone in an account gets the same variation.
• Raising a variation’s share keeps who already had it, as long as the weights stay in the same order (the console and ezgh flags rollout keep it). Going from 10% to 25% adds contexts; nobody in the first 10% loses the variation.
• Flags bucket independently: being in one flag’s 10% says nothing about another’s.
• A context without the bucketBy attribute gets the first variation with a non-zero weight, and so does one whose bucketBy value isn’t a string or an integer below 10¹⁵ (a boolean, an object, a fraction).

From the command line

For a flag with two variations, ezgh flags rollout sets the default rule: --percent goes to true for a boolean flag, else to the flag’s first variation or --variation. A default rule that’s already a rollout keeps its order and bucketing, and only its weights change.

ezgh flags rollout new-checkout --env production --percent 25 --comment "A quarter"
ezgh flags rollout new-checkout --env production --percent 25 --bucket-by companyId
ezgh flags rollout banner-color --env production --percent 10 --variation green

A rollout applies while the flag is on in that environment.