nene

nene is a command-line tool to generate Rust code for Google Cloud Spanner.
nene uses database schema to generate code by using Information Schema. nene runs SQL queries against tables in INFORMATION_SCHEMA to fetch metadata for a database, and applies the metadata to Go templates to generate code/models to acccess Cloud Spanner.

Installation

cargo install nene

Usage

```bash export RUSTLOG=info export SPANNERDSN=projects/local-project/instances/test-instance/databases/local-database

if you don't use emulator use GOOGLEAPPLICATIONCREDENTIALS instead of SPANNEREMULATORHOST

export SPANNEREMULATORHOST=localhost:9010 mkdir ./gen nene -o ./gen ```

• -i

  • template directory.
  • see template directory structure
  • if not specified default template are used.

• -o

  • output directory
  • default directory is ./gen

Generated file with default template

Default template generates the files for google-cloud-spanner.

```rust // DON'T EDIT. this code is generated by nene. use googlecloudgoogleapis::spanner::v1::Mutation; use googlecloudgax::grpc::Status; use googlecloudspanner::client::{RunInTxError, TxError}; use googlecloudspanner::key::Key; use googlecloudspanner::mutation::{ delete, insertorupdatestruct, insertstruct, replacestruct, updatestruct, }; use googlecloudspanner::reader::AsyncIterator; use googlecloudspanner::row::{Error as RowError, Row, Struct, TryFromStruct}; use googlecloudspanner::statement::{Kinds, Statement, ToKind, ToStruct, Types}; use googlecloudspanner::transaction::Transaction; use googlecloudspanner::transaction::CallOptions; use googlecloudspanner::value::CommitTimestamp; use std::convert::TryFrom;

pub const TABLENAME: &str = "User"; pub const COLUMNUSERID: &str = "UserId"; pub const COLUMNPREMIUM: &str = "Premium"; pub const COLUMNUPDATEDAT: &str = "UpdatedAt";

pub struct User { pub userid: String, pub premium: bool, pub updatedat: chrono::DateTime, }

impl User { pub fn insert(&self) -> Mutation { insertstruct(TABLENAME, &self) }

pub fn update(&self) -> Mutation { updatestruct(TABLENAME, &self) }

pub fn replace(&self) -> Mutation { replacestruct(TABLENAME, &self) }

pub fn insertorupdate(&self) -> Mutation { insertorupdatestruct(TABLENAME, &self) }

pub fn delete(&self) -> Mutation { delete(TABLENAME, Key::key(&self.userid)) }

pub async fn findbypk( tx: &mut Transaction, userid: &String, options: Option ) -> Result, RunInTxError> { let mut stmt = Statement::new("SELECT * From User WHERE UserId = @UserId"); stmt.addparam(COLUMNUSERID, userid); let mut rows = Self::readbystatement(tx, stmt, options).await?; if !rows.isempty() { Ok(rows.pop()) } else { Ok(None) } }

pub async fn readbystatement( tx: &mut Transaction, stmt: Statement, options: Option ) -> Result, RunInTxError> { let mut reader = tx.query(stmt).await?; if options.issome() { reader.setcalloptions(options.unwrap()); } let mut result = vec![]; while let Some(row) = reader.next().await? { let data = Self::tryfrom(row)?; result.push(data) } Ok(result) } }

impl ToStruct for User { fn tokinds(&self) -> Kinds { vec![ (COLUMNUSERID, self.userid.tokind()), (COLUMNPREMIUM, self.premium.tokind()), (COLUMNUPDATEDAT, CommitTimestamp::new().tokind()), ] }

fn gettypes() -> Types { vec![ (COLUMNUSERID, String::gettype()), (COLUMNPREMIUM, bool::gettype()), (COLUMNUPDATEDAT, CommitTimestamp::get_type()), ] } }

impl TryFromStruct for User { fn tryfromstruct(s: Struct<'>) -> Result { Ok(User { userid: s.columnbyname(COLUMNUSERID)?, premium: s.columnbyname(COLUMNPREMIUM)?, updatedat: s.columnbyname(COLUMNUPDATEDAT)?, }) } }

impl TryFrom for User { type Error = RowError; fn tryfrom(row: Row) -> Result { Ok(User { userid: row.columnbyname(COLUMNUSERID)?, premium: row.columnbyname(COLUMNPREMIUM)?, updatedat: row.columnbyname(COLUMNUPDATEDAT)?, }) } } ```