59 lines
2.4 KiB
Markdown
59 lines
2.4 KiB
Markdown
# UUID or else
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There are many use cases where we need to use a unique ID. In my experience, I
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only encounter 2 cases:
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- ID to trace request from client to server, from service to service
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(microservice architecture or nanoservice I don't know).
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- Primary key for database.
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In my Go universe, there are some libs to help us with this:
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- [google/uuid](https://github.com/google/uuid)
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- [rs/xid](https://github.com/rs/xid)
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- [segmentio/ksuid](https://github.com/segmentio/ksuid)
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- [oklog/ulid](https://github.com/oklog/ulid)
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## First use case is trace ID, or context aware ID
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The ID is used only for trace and log. If same ID is generated twice (because
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maybe the possibility is too small but not 0), honestly I don't care. When I use
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that ID to search log , if it pops more than things I care for, it is still no
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harm to me.
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My choice for this use case is **rs/xid**. Because it is small (not span too
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much on log line) and copy friendly.
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## Second use case is primary key, also hard choice
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Why I don't use auto increment key for primary key? The answer is simple, I
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don't want to write database specific SQL. SQLite has some different syntax from
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MySQL, and PostgreSQL and so on. Every logic I can move to application layer
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from database layer, I will.
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The ID must be sortable (because index) and unique.
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I have 3 choices:
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- **google/uuid**: use UUID v7 not v4.
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- **segmentio/ksuid**: handle error if you don't want panic.
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- **oklog/ulid**: don't use yet.
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## What else?
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I think about adding prefix to ID to identify which resource that ID represents.
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For example: `user:XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX`.
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## Thanks
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- [Universally Unique IDentifiers (UUIDs)](https://datatracker.ietf.org/doc/html/rfc9562)
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- [On IDs](https://0pointer.net/blog/projects/ids.html)
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- [UUID, SERIAL OR IDENTITY COLUMNS FOR POSTGRESQL AUTO-GENERATED PRIMARY KEYS?](https://www.cybertec-postgresql.com/en/uuid-serial-or-identity-columns-for-postgresql-auto-generated-primary-keys/)
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- [Identity Crisis: Sequence v. UUID as Primary Key](https://brandur.org/nanoglyphs/026-ids)
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- [Generating good unique ids in Go](https://blog.kowalczyk.info/article/JyRZ/generating-good-unique-ids-in-go.html)
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- [How we used Go 1.18 when designing our Identifiers](https://encore.dev/blog/go-1.18-generic-identifiers)
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- [ULIDs and Primary Keys](https://blog.daveallie.com/ulid-primary-keys)
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- [UUIDv7 in 32 languages](https://antonz.org/uuidv7/)
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