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60 lines
1.7 KiB
Markdown
60 lines
1.7 KiB
Markdown
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# What is a snapshot in GMA?
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A metadata snapshot models the current state of one or multiple metadata [aspects](aspect.md) associated with a particular [entity](entity.md).
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Each entity type is expected to have:
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1. An entity-specific aspect (e.g. `GroupAspect` from below), which is a `typeref` containing a union of all possible metadata aspects for the entity.
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2. An entity-specific snapshot (e.g. `GroupSnapshot` from below), which contains an array (aspects) of entity-specific aspects.
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```json
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{
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"type": "typeref",
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"name": "GroupAspect",
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"namespace": "com.linkedin.metadata.aspect",
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"doc": "A specific metadata aspect for a group",
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"ref": [
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"com.linkedin.group.Membership",
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"com.linkedin.group.SomeOtherMetadata"
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]
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}
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```
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```json
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{
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"type": "record",
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"name": "GroupSnapshot",
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"namespace": "com.linkedin.metadata.snapshot",
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"doc": "A metadata snapshot for a specific group entity.",
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"fields": [
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{
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"name": "urn",
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"type": "com.linkedin.common.CorpGroupUrn",
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"doc": "URN for the entity the metadata snapshot is associated with."
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},
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{
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"name": "aspects",
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"doc": "The list of metadata aspects associated with the group.",
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"type": {
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"type": "array",
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"items": "com.linkedin.metadata.aspect.GroupAspect"
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}
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}
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]
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}
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```
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The generic `Snapshot` typeref contains a union of all entity-specific snapshots and can therefore be used to represent the state of any metadata aspect for all supported entity types.
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```json
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{
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"type": "typeref",
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"name": "Snapshot",
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"namespace": "com.linkedin.metadata.snapshot",
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"doc": "A union of all supported metadata snapshot types.",
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"ref": [
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"DatasetSnapshot",
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"GroupSnapshot",
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"UserSnapshot"
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]
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}
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```
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