Add language SDK specification #369
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Signed-off-by: Michael Gasch <15986659+embano1@users.noreply.github.com>
Signed-off-by: Michael Gasch <15986659+embano1@users.noreply.github.com>
| Invocation 1: | ||
| - Load state: [] | ||
| - Start STEP(id="step1") | ||
| - Checkpoint: START step1 |
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I guess we need more guidance here around:
- AT-LEAST/MOST-ONCE
- batching/optimizations
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Yeah - that would be a good idea.
| - Be checkpointed and resumed | ||
| - Maintain execution state across interruptions | ||
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| The two core durable operation primitives are: |
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There are 5 primitives (if you ignore the EXECUTION operation which is only used to complete the execution):
CALLBACKCHAINED_INVOKECONTEXTSTEPWAIT
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| For correct replay behavior, **user code MUST be deterministic**: | ||
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| 1. Non-durable code (code outside operations) MUST execute identically on each replay |
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One thing we should note is that this may require re-implementing/providing alternatives for certain language constructs that are inherently nondeterministic.
For example in Java unless you use a LinkedHashMap instead of a HashMap, the iteration order is not guaranteed to be the same on multiple creations of the same map, or in Go where map iteration order is purposefully randomized, etc.
| "CheckpointToken": "string", | ||
| "InitialExecutionState": { | ||
| "Operations": [ | ||
| /* Operation objects */ |
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Should we link to the Lambda API docs sections where appropriate in this doc? E.g. https://docs.aws.amazon.com/lambda/latest/api/API_Operation.html
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| The SDK CANNOT: | ||
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| - Prevent users from writing non-deterministic code |
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I mean if it is somehow able to, it should 😄 - the spec shouldn't prevent it from doing so
Maybe this should say "The SDK is not responsible for:"
| "Error": { | ||
| "ErrorType": "string", | ||
| "ErrorMessage": "string", | ||
| "StackTrace": ["string"] // OPTIONAL |
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All the fields are actually optional
(There's also a 4th ErrorData field as well for additional machine-readable error data)
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| - Maximum execution duration: 1 year | ||
| - Maximum response payload: 6MB | ||
| - Maximum history size: Limited by service quotas |
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Maximum number of durable operations (including retries)? The limit is not directly on history.
| Invocation 1: | ||
| - Load state: [] | ||
| - Start STEP(id="step1") | ||
| - Checkpoint: START step1 |
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Yeah - that would be a good idea.
| - Load state: [step1: SUCCEEDED, step2: STARTED] | ||
| - Replay STEP(id="step1") - return cached "result1" | ||
| - Resume STEP(id="step2") | ||
| - Checkpoint: START step2 (same ID, continues) |
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You wouldn't checkpoint START again - it's already started. Depends on semantics but can either run it again then checkpoint success/failure/retry or decide to immediately checkpoint failure, or retry, etc.
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| ``` | ||
| [callback_promise, callback_id] = await context.create_callback("approval") | ||
| await send_approval_email(callback_id) |
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probably want to put this in a context.step
| │ START action | ||
| ▼ | ||
| ┌─────────┐ | ||
| │ STARTED │◄──────┐ |
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the arrow here should be coming from READY
2 participants
Issue #, if available: n/a
Description of changes:
Provide a language SDK specification for developers to build their own SDKs and establish conformance testing. This is just a first start to iterate on the SDK and provide builders guidance given the large interest in additional SDKs (Go, Rust, Java, Swift, .NET). The file should then be extracted into its own repository to create conformance tests for officially supported SDKs.
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