Behavior patterns

Chronicle.Patterns provides an idiomatic Elixir API over the behavior patterns Chronicle mines from the event history of an event store — recurring combinations of facets (Day, TimeBucket, CommandType, AggregateType, and so on) that survived its support and confidence thresholds.

An empty result from any of these functions is an answer, not a failure: it says the scope has no established behavior for the asked context. Nothing is invented to fill the gap, so a caller can treat “no patterns” as “do not claim to know”.

Asking about a moment

The question an application actually has is usually “what does this person usually do right now” — not an arbitrary facet combination. get_patterns_at/3 is that question:

{:ok, patterns} = Chronicle.Patterns.get_patterns_at("user-42")

Day and TimeBucket are derived from the moment using its own offset, not UTC, with the same rule the kernel used when it mined the patterns — a scope’s established morning behavior is asked about in their own morning, wherever they are. The moment defaults to now; pass one explicitly to ask about a different time:

{:ok, patterns} = Chronicle.Patterns.get_patterns_at("user-42", tomorrow_morning)

Narrow the question with more of the situation using :also_constraining — asking about a moment and asking about a kind of work are the same call rather than two competing ones:

{:ok, patterns} =
  Chronicle.Patterns.get_patterns_at(
    "user-42",
    nil,
    also_constraining: %{Chronicle.Patterns.FacetName.aggregate_type() => "Invoice"}
  )

A result names the action it answers for through Chronicle.Patterns.FacetName.command_type():

action = pattern.facets[Chronicle.Patterns.FacetName.command_type()]

The low-level facet-set query

get_patterns_at/3 is a wrapper, not a replacement — get_patterns/3 and get_usual_actions/3 stay available for a context built by hand:

context = %{
  Chronicle.Patterns.FacetName.day() => "Monday",
  Chronicle.Patterns.FacetName.time_bucket() => "Morning"
}

{:ok, patterns} = Chronicle.Patterns.get_patterns("user-42", context)
{:ok, actions} = Chronicle.Patterns.get_usual_actions("user-42", context)

get_patterns/3 returns patterns that describe a situation; get_usual_actions/3 returns the ones that say what is done in it, at most one answer per action.

Inspecting what has been mined

{:ok, patterns} = Chronicle.Patterns.get_patterns_for_scope("user-42")
{:ok, scopes} = Chronicle.Patterns.get_scopes()

The time bucket rule

Chronicle.Patterns.time_bucket/1 exposes the same part-of-day rule the kernel mined with, so an application never writes its own copy of it — getting it wrong means asking about a slot the mining never used, which looks exactly like “nothing is established here”:

Hours	Bucket
05:00–08:00	:early_morning
08:00–11:00	:morning
11:00–14:00	:midday
14:00–17:00	:afternoon
17:00–22:00	:evening
22:00–05:00	:night

Chronicle.Patterns.time_bucket(DateTime.utc_now())

Options

Every function accepts:

• :client — the client name (default: Chronicle.Client)
• :namespace — overrides the client’s configured namespace
• :minimum_confidence — the lowest confidence (0.0–1.0) an answer may hold; defaults to the server’s configured threshold
• :max_results — the largest number of answers to return; defaults to the server’s default

Not supported

AllPatterns (every mined pattern for an event store, regardless of scope) is not exposed, matching the .NET client’s IPatterns.