&str-based FromSql impls for firewall/route types#8303
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A few types (target & filter specifications, ranges) associated with firewall rules and routes rely on a custom string-based representation in CRDB. However, when deserializing them today we end up cycling through `PgValue`->`String`->`ParsedEnumType`, needlessly allocating and copying strings per element. This PR prevents us from doing so by generating these `impl`s for any type which implements the existing `DatabaseString` trait. While there are more types in `nexus-db-model` using `FromSql<Text, _>`, most seem to make use of a `String` internally regardless, so there's no immediate benefit (other than consistency) in changing them up at this time. Motivated by some of the discussion in #8194.
FelixMcFelix
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Jun 10, 2025
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| impl ::diesel::deserialize::FromSql<::diesel::sql_types::Text, ::diesel::pg::Pg> for $model_type { | ||
| fn from_sql(bytes: <::diesel::pg::Pg as ::diesel::backend::Backend>::RawValue<'_>) | ||
| -> ::diesel::deserialize::Result<Self> | ||
| { | ||
| Ok($model_type::from_database_string(::std::str::from_utf8(bytes.as_bytes())?)?) | ||
| } | ||
| } | ||
| } | ||
| } |
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Worth pointing out that we could have this work for all DB: Backend, but we'd need to rely on a little unsafe to use the *const str: FromSql<sql_types::Text, DB>, bound.
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hawkw
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Jun 13, 2025
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Thanks to taking the time to look into this! This looks good to me!
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A few types (target & filter specifications, ranges) associated with firewall rules and routes rely on a custom string-based representation in CRDB. However, when deserializing them today we end up cycling through
PgValue->String->ParsedEnumType, needlessly allocating and copying strings per element. This PR prevents us from doing so by generating theseimpls for any type which implements the existingDatabaseStringtrait.While there are more types in
nexus-db-modelusingFromSql<Text, _>, most seem to make use of aStringinternally regardless, so there's no immediate benefit (other than consistency) in changing them up at this time.Motivated by some of the discussion in #8194.