2023-05-02 10:33:06 -05:00
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// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: MPL-2.0
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2018-06-08 18:18:30 -05:00
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// Package statemgr defines the interfaces and some supporting functionality
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2019-03-01 10:59:01 -06:00
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// for "state managers", which are components responsible for writing state
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2018-06-08 18:18:30 -05:00
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// to some persistent storage and then later retrieving it.
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//
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// State managers will usually (but not necessarily) use the state file formats
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// implemented in the sibling directory "statefile" to serialize the persistent
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// parts of state for storage.
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//
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// State managers are responsible for ensuring that stored state can be updated
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// safely across multiple, possibly-concurrent Terraform runs (with reasonable
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// constraints and limitations). The rest of Terraform considers state to be
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// a mutable data structure, with state managers preserving that illusion
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// by creating snapshots of the state and updating them over time.
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//
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// From the perspective of callers of the general state manager API, a state
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// manager is able to return the latest snapshot and to replace that snapshot
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// with a new one. Some state managers may also preserve historical snapshots
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// using facilities offered by their storage backend, but this is always an
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// implementation detail: the historical versions are not visible to a user
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// of these interfaces.
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package statemgr
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