DA-05 · LESSON 05

Atomic snapshot promotion

KEY DEFINITIONS

Terms used in this lesson

HTTP: Hypertext Transfer Protocol: a request-and-response protocol commonly used between web services.
Nostr: A signed-event messaging protocol; Ducat can use relays to distribute oracle material without making those relays Bitcoin validators.

The current snapshot is published only after its complete ladder succeeds, allowing clients to stay on the prior coherent snapshot after partial failure.

35 min Difficulty 4/5 Not started

VISUAL MODEL

See the whole mechanism before going step by step

Use the diagrams to orient yourself. Then the guided explanation below teaches every part in depth.

4 explanatory views

CONCEPT-SPECIFIC MAP · ducat vaultA Ducat action moves one Bitcoin-anchored vault state to a successorSelect any state to inspect its exact role.

RELATIONSHIP MAPInputs, rule, and outputs

01
PREDECESSORCurrent vault outpoint
The current Bitcoin output anchors collateral and identifies the state being spent.
02
REQUESTAtomic snapshot promotion
The Atomic snapshot promotion workflow proposes one exact action and successor state.
03
POLICYProfile, oracle, signatures
Applicable policy, price evidence, authorization, and transaction shape are checked.
04
BITCOIN SPENDScript-valid transaction
Bitcoin miners and nodes can include only a transaction that satisfies Bitcoin rules.
05
SUCCESSORNew outpoint and state
Ducat validators reconstruct debt, collateral, token, and account changes from the confirmed transaction.

Rule shown: Bitcoin checks the spend; Ducat components independently reconstruct and validate the additional protocol state.

STAGE 1 OF 5PREDECESSOR: Current vault outpoint

The current Bitcoin output anchors collateral and identifies the state being spent.

Governing relationship: Bitcoin checks the spend; Ducat components independently reconstruct and validate the additional protocol state. Complete path: 1. PREDECESSOR, Current vault outpoint. The current Bitcoin output anchors collateral and identifies the state being spent. 2. REQUEST, Atomic snapshot promotion. The Atomic snapshot promotion workflow proposes one exact action and successor state. 3. POLICY, Profile, oracle, signatures. Applicable policy, price evidence, authorization, and transaction shape are checked. 4. BITCOIN SPEND, Script-valid transaction. Bitcoin miners and nodes can include only a transaction that satisfies Bitcoin rules. 5. SUCCESSOR, New outpoint and state. Ducat validators reconstruct debt, collateral, token, and account changes from the confirmed transaction.

1. State transitionWhat exists, what changes, and what results

BEFORE

Snapshot A is the current kind 10000 event. A new cycle for snapshot B must publish one kind 10001 pending event, 866 kind 30000 contracts in seven chunks, and one kind 10000…

MECHANISM

The workflow first emits a kind 10001 pending snapshot for observability.

AFTER

Atomic here means ordered pointer promotion. It does not mean simultaneous relay delivery or rollback of already published Nostr events.

Text equivalent: Starting from Snapshot A is the current kind 10000 event. A new cycle for snapshot B must publish one kind 10001 pending event, 866 kind 30000 contracts in seven chunks, and one kind 10000 current event. The mechanism begins when The workflow first emits a kind 10001 pending snapshot for observability. The resulting lesson is Atomic here means ordered pointer promotion. It does not mean simultaneous relay delivery or rollback of already published Nostr events.

2. Mechanism pathSelect a stage to inspect its job

STAGE 1 OF 4

Publish pending state

The workflow first emits a kind 10001 pending snapshot for observability.

Complete path: 1. Publish pending state: The workflow first emits a kind 10001 pending snapshot for observability. 2. Publish the full ladder: All kind 30000 threshold events are sent in bounded chunks under the workflow HTTP-call limit. 3. Stop on partial failure: If any ladder chunk fails, the cycle returns an error and does not publish the new current snapshot. 4. Promote only after success: Kind 10000 is published last, telling wallets that this coherent base snapshot and ladder are ready.

3. Rule and failure boundaryWhat accepts the result and where it can stop

ACCEPTED PATH

The worked case executes the named inputs and checks in the displayed order. Kind 10000 is published last, telling wallets that this coherent base snapshot and ladder are ready.

CHANGED CONDITION

A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. It means the workflow does not promote the new current pointer until its complete ladder publish sequence succeeds.

Important distinction: Atomic means every Nostr relay receives all events at exactly the same instant. It means the workflow does not promote the new current pointer until its complete ladder publish sequence succeeds.

Text equivalent: The accepted path is enforced by The worked case executes the named inputs and checks in the displayed order. Kind 10000 is published last, telling wallets that this coherent base snapshot and ladder are ready. If the required condition changes, A missing, malformed, stale, unauthorized, or inconsistent required input stops at its first named boundary. It means the workflow does not promote the new current pointer until its complete ladder publish sequence succeeds.

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Learn the idea

Atomic promotion means wallets are shown a new current snapshot only after the full threshold ladder for that snapshot is available. It prevents a client from combining a new base price with missing or old threshold contracts.

GUIDED EXPLANATION1/4 ideas inspected

Publish pending state

The workflow first emits a kind 10001 pending snapshot for observability.

The worked example follows the explanation

Inspect every idea above to open it.

Important distinction“Atomic means every Nostr relay receives all events at exactly the same instant.”

It means the workflow does not promote the new current pointer until its complete ladder publish sequence succeeds.

FINISH LEARNING FIRST

The questions unlock after every required learning activity

Inspect every guided idea, open the worked example, rebuild its mechanism, and complete the deterministic lesson tool. Your progress is saved automatically.