Chrono support

[dean-shaff]

Summary

Add support for chrono.

Checklist

Delete items not relevant to your PR:

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided so that we can include it in CHANGELOG later
• For significant changes, documentation in README and https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

[CLAassistant]

All committers have signed the CLA.

[serprex]

https://docs.rs/chrono/latest/chrono/serde/ts_microseconds/index.html should give microsecond precision, fixing CI

[loyd]

Thanks for your contribution!

[slvrtrn]

@dean-shaff, can you please sign the CLA? We won't be able to merge without it.

[StashOfCode]

When is this getting released?

[StashOfCode]

Hey, if you add a mod with DateTime::<Utc>::from_str, some types of datetime strings would become insertable into Clickhouse, e.g. 2025-01-19 16:36:15.157350+00:00.
See https://docs.rs/chrono/latest/src/chrono/datetime/mod.rs.html#1816-1818

pub mod dt_from_str {
    use super::*;

    // type DateTimeUtc = DateTime<Utc>;

    // option!(
    //     DateTimeUtc,
    //     "Ser/de `Option<DateTime<Utc>>` to/from `Nullable(DateTime)`."
    // );

    pub fn serialize<S>(dt: &DateTime<Utc>, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        let ts: i64 = dt.timestamp();

        u32::try_from(ts)
            .map_err(|_| S::Error::custom(format!("{dt} cannot be represented as DateTime")))?
            .serialize(serializer)
    }

    pub fn deserialize<'de, D>(deserializer: D) -> Result<DateTime<Utc>, D::Error>
    where
        D: Deserializer<'de>,
    {
        let ts: String = Deserialize::deserialize(deserializer)?;
        DateTime::<Utc>::from_str(&ts).map_err(|_| {
            D::Error::custom(format!("{ts} cannot be converted to DateTime<Utc>"))
        })
    }


#[derive(Serialize, Deserialize, Debug, Row)]
pub struct MyRow {
    pub id: String,
    #[serde(with = "dt_from_str")]
    pub requested_at: DateTime<Utc>,

[dean-shaff]

@StashOfCode I think my intention with this PR was the replicate the existing time functionality; I'd be happy to add those string conversions in a new PR; what do you think?

[slvrtrn]

@loyd

Merging is blocked
Merging can be performed automatically once the requested changes are addressed.

If everything is OK with this PR, let's merge and release it with the current pending changes as 0.14.0?

[loyd]

LGTM, let's merge

[StashOfCode]

@dean-shaff, I found a crate called serde_with that seems to have already implemented what I did for myself. The documentation is pretty bad there though :/