2bef715211
Source commit: 20b59dc46b72103c2f8a516c692b5cc3d54fab19 Public tree identity: sha256:aaa5ac7b58b2a0d23c6b11e5f76324bf3839ca1f62653a83deb736932adcfbd9
45 lines
2.2 KiB
Markdown
45 lines
2.2 KiB
Markdown
# Task ABI
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The MVP task ABI is a small, versioned contract between a compiled workflow
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module and the coordinator-main or node Wasmtime host. It is intentionally
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narrower than WASI and should grow only when the flagship workflow needs
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another host operation.
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## Assignment
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Each assignment carries a `TaskSpec` containing the virtual process and task
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identity, bundle module, declared Wasm export and ABI version, serialized
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arguments, required capabilities and artifacts, selected environment, and VFS
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epoch. The node rejects a missing or incompatible spec rather than guessing an
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entrypoint.
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SDK task macros generate exports that decode versioned boundary values, invoke
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the Rust function, and encode the result. Values crossing a task boundary are
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limited to serializable data and Disasmer handles; host-only objects fail at
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compile time.
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## Host imports
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The current guest imports cover task spawn/join, command execution,
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cancellation observation, source snapshots, VFS file operations, artifact
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publication, and debug probes. Every import validates memory ranges and payload
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sizes. The coordinator main receives only spawn/join, waiting, bounded state,
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and debug controls; node hosts check the assignment's declared capabilities
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before performing source, command, network, or artifact operations.
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`disasmer.command_run_v1` runs a command through the selected environment
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backend. On Linux, a task assigned to an environment requiring rootless Podman
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uses the normal Podman assignment path. The hosted community policy does not
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grant this on managed infrastructure; a user node may grant it for its own
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machine.
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## Lifecycle
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Cooperative cancellation is visible to guest code at a host boundary. Forced
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abort arms Wasmtime epoch interruption and also terminates active environment
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work. Debug freeze and resume synchronize at acknowledged host or Wasmtime epoch
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boundaries. These controls do not claim instruction-accurate source stepping.
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Each task assignment captures a restart-compatibility hash and clean VFS entry
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boundary. DAP task restart rebuilds the bundle and accepts edited code only when
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the task ABI, declared capabilities, environment, arguments, handles, and VFS
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boundary remain compatible.
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