Struct google_cloud_spanner::apiv1::spanner_client::Client

pub struct Client { /* private fields */ }

Implementations

impl Client

pub fn new(inner: SpannerClient<Channel>) -> Client

create new spanner client

Examples found in repository

src/apiv1/conn_pool.rs (line 30)

    pub fn conn(&self) -> Client {
        let conn = self.inner.conn();
        Client::new(SpannerClient::new(conn))
    }

pub async fn create_session(
    &mut self,
    req: CreateSessionRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<Session>, Status>

create_session creates a new session. A session can be used to perform transactions that read and/or modify data in a Cloud Spanner database. Sessions are meant to be reused for many consecutive transactions.

Sessions can only execute one transaction at a time. To execute multiple concurrent read-write/write-only transactions, create multiple sessions. Note that standalone reads and queries use a transaction internally, and count toward the one transaction limit.

Active sessions use additional server resources, so it is a good idea to delete idle and unneeded sessions. Aside from explicit deletes, Cloud Spanner may delete sessions for which no operations are sent for more than an hour. If a session is deleted, requests to it return NOT_FOUND.

Idle sessions can be kept alive by sending a trivial SQL query periodically, e.g., “SELECT 1”.

pub async fn batch_create_sessions(
    &mut self,
    req: BatchCreateSessionsRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<BatchCreateSessionsResponse>, Status>

batch_create_sessions creates multiple new sessions.

This API can be used to initialize a session cache on the clients. See https:///goo.gl/TgSFN2 (at https:///goo.gl/TgSFN2) for best practices on session cache management.

Examples found in repository

src/session.rs (line 626)

async fn batch_create_session(
    mut spanner_client: Client,
    database: String,
    creation_count: usize,
) -> Result<Vec<SessionHandle>, Status> {
    let request = BatchCreateSessionsRequest {
        database,
        session_template: None,
        session_count: creation_count as i32,
    };

    tracing::debug!("spawn session creation request : count to create = {}", creation_count);
    let response = spanner_client
        .batch_create_sessions(request, None, None)
        .await?
        .into_inner();

    let now = Instant::now();
    Ok(response
        .session
        .into_iter()
        .map(|s| SessionHandle::new(s, spanner_client.clone(), now))
        .collect::<Vec<SessionHandle>>())
}

pub async fn get_session(
    &mut self,
    req: GetSessionRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<Session>, Status>

get_session gets a session. Returns NOT_FOUND if the session does not exist. This is mainly useful for determining whether a session is still alive.

pub async fn list_sessions(
    &mut self,
    req: ListSessionsRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<ListSessionsResponse>, Status>

list_sessions lists all sessions in a given database.

pub async fn delete_session(
    &mut self,
    req: DeleteSessionRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<()>, Status>

delete_session ends a session, releasing server resources associated with it. This will asynchronously trigger cancellation of any operations that are running with this session.

Examples found in repository

src/session.rs (line 64)

    async fn invalidate(&mut self) {
        tracing::debug!("session invalidate {}", self.session.name);
        let request = DeleteSessionRequest {
            name: self.session.name.to_string(),
        };
        match self.spanner_client.delete_session(request, None, None).await {
            Ok(_s) => self.valid = false,
            Err(e) => {
                tracing::error!("session remove error {} error={:?}", self.session.name, e);
            }
        }
    }
}

/// ManagedSession
pub struct ManagedSession {
    session_pool: SessionPool,
    session: Option<SessionHandle>,
}

impl ManagedSession {
    pub(crate) fn new(session_pool: SessionPool, session: SessionHandle) -> Self {
        ManagedSession {
            session_pool,
            session: Some(session),
        }
    }
}

impl Drop for ManagedSession {
    fn drop(&mut self) {
        let session = self.session.take().unwrap();
        self.session_pool.recycle(session);
    }
}

impl Deref for ManagedSession {
    type Target = SessionHandle;

    fn deref(&self) -> &Self::Target {
        self.session.as_ref().unwrap()
    }
}

impl DerefMut for ManagedSession {
    fn deref_mut(&mut self) -> &mut Self::Target {
        self.session.as_mut().unwrap()
    }
}

pub struct Sessions {
    sessions: VecDeque<SessionHandle>,
    inuse: usize,
}

impl Sessions {
    fn grow(&mut self, session: SessionHandle) {
        self.sessions.push_back(session);
    }

    fn num_opened(&self) -> usize {
        self.inuse + self.sessions.len()
    }

    fn take(&mut self) -> Option<SessionHandle> {
        match self.sessions.pop_front() {
            None => None,
            Some(s) => {
                self.inuse += 1;
                Some(s)
            }
        }
    }

    fn release(&mut self, session: SessionHandle) {
        self.inuse -= 1;
        if session.valid {
            self.sessions.push_back(session);
        }
    }
}

pub struct SessionPool {
    inner: Arc<Mutex<Sessions>>,
    waiters: Arc<Waiters>,
    allocation_request_sender: broadcast::Sender<bool>,
}

impl SessionPool {
    async fn new(
        database: String,
        conn_pool: &ConnectionManager,
        min_opened: usize,
        allocation_request_sender: broadcast::Sender<bool>,
    ) -> Result<Self, Status> {
        let init_pool = Self::init_pool(database, conn_pool, min_opened).await?;
        let waiters = Arc::new(Waiters::new(VecDeque::new()));

        Ok(SessionPool {
            inner: Arc::new(Mutex::new(Sessions {
                sessions: init_pool,
                inuse: 0,
            })),
            waiters,
            allocation_request_sender,
        })
    }

    async fn init_pool(
        database: String,
        conn_pool: &ConnectionManager,
        min_opened: usize,
    ) -> Result<VecDeque<SessionHandle>, Status> {
        let channel_num = conn_pool.num();
        let creation_count_per_channel = min_opened / channel_num;

        let mut sessions = Vec::<SessionHandle>::new();
        for _ in 0..channel_num {
            let next_client = conn_pool.conn();
            match batch_create_session(next_client, database.clone(), creation_count_per_channel).await {
                Ok(r) => {
                    for i in r {
                        sessions.push(i);
                    }
                }
                Err(e) => return Err(e),
            }
        }
        tracing::debug!("initial session created count = {}", sessions.len());
        Ok(sessions.into())
    }

    fn request(&self) -> oneshot::Receiver<SessionHandle> {
        let (sender, receiver) = oneshot::channel();
        {
            self.waiters.lock().push_back(sender);
        }
        let _ = self.allocation_request_sender.send(true);
        receiver
    }

    fn num_opened(&self) -> usize {
        self.inner.lock().num_opened()
    }

    fn num_waiting(&self) -> usize {
        self.waiters.lock().len()
    }

    fn grow(&self, mut sessions: Vec<SessionHandle>) {
        while let Some(session) = sessions.pop() {
            match { self.waiters.lock().pop_front() } {
                Some(c) => {
                    let mut inner = self.inner.lock();
                    match c.send(session) {
                        Err(session) => inner.grow(session),
                        _ => {
                            // Mark as using when notify to waiter directory.
                            inner.inuse += 1
                        }
                    };
                }
                None => self.inner.lock().grow(session),
            };
        }
    }

    fn recycle(&self, session: SessionHandle) {
        if session.valid {
            tracing::trace!("recycled name={}", session.session.name);
            match { self.waiters.lock().pop_front() } {
                Some(c) => {
                    if let Err(session) = c.send(session) {
                        self.inner.lock().release(session)
                    }
                }
                None => self.inner.lock().release(session),
            };
        } else {
            self.inner.lock().release(session);

            // request session creation
            let _ = self.allocation_request_sender.send(true);
        }
    }
}

impl Clone for SessionPool {
    fn clone(&self) -> Self {
        SessionPool {
            inner: Arc::clone(&self.inner),
            waiters: Arc::clone(&self.waiters),
            allocation_request_sender: self.allocation_request_sender.clone(),
        }
    }
}

#[derive(Clone, Debug)]
pub struct SessionConfig {
    /// max_opened is the maximum number of opened sessions allowed by the session
    /// pool. If the client tries to open a session and there are already
    /// max_opened sessions, it will block until one becomes available or the
    /// context passed to the client method is canceled or times out.
    pub max_opened: usize,

    /// min_opened is the minimum number of opened sessions that the session pool
    /// tries to maintain. Session pool won't continue to expire sessions if
    /// number of opened connections drops below min_opened. However, if a session
    /// is found to be broken, it will still be evicted from the session pool,
    /// therefore it is posssible that the number of opened sessions drops below
    /// min_opened.
    pub min_opened: usize,

    /// max_idle is the maximum number of idle sessions, pool is allowed to keep.
    pub max_idle: usize,

    /// idle_timeout is the wait time before discarding an idle session.
    /// Sessions older than this value since they were last used will be discarded.
    /// However, if the number of sessions is less than or equal to min_opened, it will not be discarded.
    pub idle_timeout: std::time::Duration,

    pub session_alive_trust_duration: std::time::Duration,

    /// session_get_timeout is the maximum value of the waiting time that occurs when retrieving from the connection pool when there is no idle session.
    pub session_get_timeout: std::time::Duration,

    /// refresh_interval is the interval of cleanup and health check functions.
    pub refresh_interval: std::time::Duration,

    /// incStep is the number of sessions to create in one batch when at least
    /// one more session is needed.
    inc_step: usize,
}

impl Default for SessionConfig {
    fn default() -> Self {
        SessionConfig {
            max_opened: 400,
            min_opened: 10,
            max_idle: 300,
            inc_step: 25,
            idle_timeout: std::time::Duration::from_secs(30 * 60),
            session_alive_trust_duration: std::time::Duration::from_secs(55 * 60),
            session_get_timeout: std::time::Duration::from_secs(1),
            refresh_interval: std::time::Duration::from_secs(5 * 60),
        }
    }
}

pub struct SessionManager {
    session_pool: SessionPool,
    session_get_timeout: Duration,
    cancel: CancellationToken,
    tasks: Vec<JoinHandle<()>>,
}

#[derive(thiserror::Error, Debug)]
pub enum SessionError {
    #[error("session get time out")]
    SessionGetTimeout,
    #[error("failed to create session")]
    FailedToCreateSession,
    #[error(transparent)]
    GRPC(#[from] Status),
}

impl TryAs<Status> for SessionError {
    fn try_as(&self) -> Option<&Status> {
        match self {
            SessionError::GRPC(e) => Some(e),
            _ => None,
        }
    }
}

impl SessionManager {
    pub async fn new(
        database: impl Into<String>,
        conn_pool: ConnectionManager,
        config: SessionConfig,
    ) -> Result<SessionManager, Status> {
        let database = database.into();
        let (sender, receiver) = broadcast::channel(1);
        let session_pool = SessionPool::new(database.clone(), &conn_pool, config.min_opened, sender).await?;

        let cancel = CancellationToken::new();
        let session_get_timeout = config.session_get_timeout;
        let task_cleaner = schedule_refresh(config.clone(), session_pool.clone(), cancel.clone());
        let task_listener = listen_session_creation_request(
            config,
            session_pool.clone(),
            database,
            conn_pool,
            receiver,
            cancel.clone(),
        );

        let sm = SessionManager {
            session_get_timeout,
            session_pool,
            cancel,
            tasks: vec![task_cleaner, task_listener],
        };
        Ok(sm)
    }

    pub fn num_opened(&self) -> usize {
        self.session_pool.num_opened()
    }

    pub fn session_waiters(&self) -> usize {
        self.session_pool.num_waiting()
    }

    pub async fn get(&self) -> Result<ManagedSession, SessionError> {
        if let Some(mut s) = self.session_pool.inner.lock().take() {
            s.last_used_at = Instant::now();
            return Ok(ManagedSession::new(self.session_pool.clone(), s));
        }

        // Wait for the session creation.
        match timeout(self.session_get_timeout, self.session_pool.request()).await {
            Ok(Ok(mut session)) => {
                session.last_used_at = Instant::now();
                Ok(ManagedSession {
                    session_pool: self.session_pool.clone(),
                    session: Some(session),
                })
            }
            _ => Err(SessionError::SessionGetTimeout),
        }
    }

    pub(crate) async fn close(&self) {
        if self.cancel.is_cancelled() {
            return;
        }
        self.cancel.cancel();
        sleep(Duration::from_secs(1)).await;
        for task in &self.tasks {
            task.abort();
        }
        let deleting_sessions = {
            let mut lock = self.session_pool.inner.lock();
            let mut deleting_sessions = Vec::with_capacity(lock.sessions.len());
            while let Some(session) = lock.sessions.pop_front() {
                deleting_sessions.push(session);
            }
            deleting_sessions
        };
        for mut session in deleting_sessions {
            delete_session(&mut session).await;
        }
    }
}

fn listen_session_creation_request(
    config: SessionConfig,
    session_pool: SessionPool,
    database: String,
    conn_pool: ConnectionManager,
    mut rx: broadcast::Receiver<bool>,
    cancel: CancellationToken,
) -> JoinHandle<()> {
    tokio::spawn(async move {
        let mut allocation_request_size = 0;
        loop {
            select! {
                _ = rx.recv() => {},
                _ = cancel.cancelled() => break
            }
            let num_opened = session_pool.num_opened();
            if num_opened >= config.min_opened && allocation_request_size >= session_pool.num_waiting() {
                continue;
            }

            let mut creation_count = config.max_opened - num_opened;
            if creation_count > config.inc_step {
                creation_count = config.inc_step;
            }
            if creation_count == 0 {
                continue;
            }
            allocation_request_size += creation_count;

            let database = database.clone();
            let next_client = conn_pool.conn();

            match batch_create_session(next_client, database, creation_count).await {
                Ok(fresh_sessions) => {
                    allocation_request_size -= creation_count;
                    session_pool.grow(fresh_sessions)
                }
                Err(e) => {
                    allocation_request_size -= creation_count;
                    tracing::error!("failed to create new sessions {:?}", e)
                }
            };
        }
        tracing::trace!("stop session creating listener")
    })
}

fn schedule_refresh(config: SessionConfig, session_pool: SessionPool, cancel: CancellationToken) -> JoinHandle<()> {
    let start = Instant::now() + config.refresh_interval;
    let mut interval = tokio::time::interval_at(start.into(), config.refresh_interval);

    tokio::spawn(async move {
        loop {
            select! {
                _ = interval.tick() => {},
                _ = cancel.cancelled() => break
            }
            let now = Instant::now();
            let max_removing_count = session_pool.num_opened() as i64 - config.max_idle as i64;
            if max_removing_count < 0 {
                health_check(
                    now + Duration::from_nanos(1),
                    config.session_alive_trust_duration,
                    &session_pool,
                    cancel.clone(),
                )
                .await;
                continue;
            }

            shrink_idle_sessions(
                now,
                config.idle_timeout,
                &session_pool,
                max_removing_count as usize,
                cancel.clone(),
            )
            .await;
            health_check(
                now + Duration::from_nanos(1),
                config.session_alive_trust_duration,
                &session_pool,
                cancel.clone(),
            )
            .await;
        }
        tracing::trace!("stop session cleaner")
    })
}

async fn health_check(
    now: Instant,
    session_alive_trust_duration: Duration,
    sessions: &SessionPool,
    cancel: CancellationToken,
) {
    let sleep_duration = Duration::from_millis(10);
    loop {
        select! {
            _ = sleep(sleep_duration) => {},
            _ = cancel.cancelled() => break
        }
        let mut s = {
            // temporary take
            let mut locked = sessions.inner.lock();
            match locked.take() {
                Some(mut s) => {
                    // all the session check complete.
                    if s.last_checked_at == now {
                        locked.release(s);
                        break;
                    }
                    if std::cmp::max(s.last_used_at, s.last_pong_at) + session_alive_trust_duration >= now {
                        s.last_checked_at = now;
                        locked.release(s);
                        continue;
                    }
                    s
                }
                None => break,
            }
        };

        let request = ping_query_request(s.session.name.clone());
        match s.spanner_client.execute_sql(request, None, None).await {
            Ok(_) => {
                s.last_checked_at = now;
                s.last_pong_at = now;
                sessions.recycle(s);
            }
            Err(_) => {
                delete_session(&mut s).await;
                s.valid = false;
                sessions.recycle(s);
            }
        }
    }
}

async fn shrink_idle_sessions(
    now: Instant,
    idle_timeout: Duration,
    session_pool: &SessionPool,
    max_shrink_count: usize,
    cancel: CancellationToken,
) {
    let mut removed_count = 0;
    let sleep_duration = Duration::from_millis(10);
    loop {
        if removed_count >= max_shrink_count {
            break;
        }

        select! {
            _ = sleep(sleep_duration) => {},
            _ = cancel.cancelled() => break
        }

        // get old session
        let mut s = {
            // temporary take
            let mut locked = session_pool.inner.lock();
            match locked.take() {
                Some(mut s) => {
                    // all the session check complete.
                    if s.last_checked_at == now {
                        locked.release(s);
                        break;
                    }
                    if s.last_used_at + idle_timeout >= now {
                        s.last_checked_at = now;
                        locked.release(s);
                        continue;
                    }
                    s
                }
                None => break,
            }
        };

        removed_count += 1;
        delete_session(&mut s).await;
        s.valid = false;
        session_pool.recycle(s);
    }
}

async fn delete_session(session: &mut SessionHandle) {
    let session_name = &session.session.name;
    let request = DeleteSessionRequest {
        name: session_name.to_string(),
    };
    match session.spanner_client.delete_session(request, None, None).await {
        Ok(_) => {}
        Err(e) => tracing::error!("failed to delete session {}, {:?}", session_name, e),
    }
}

pub async fn execute_sql(
    &mut self,
    req: ExecuteSqlRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<ResultSet>, Status>

execute_sql executes an SQL statement, returning all results in a single reply. This method cannot be used to return a result set larger than 10 MiB; if the query yields more data than that, the query fails with a FAILED_PRECONDITION error.

Operations inside read-write transactions might return ABORTED. If this occurs, the application should restart the transaction from the beginning. See Transaction for more details.

Larger result sets can be fetched in streaming fashion by calling ExecuteStreamingSql instead.

Examples found in repository

src/transaction_rw.rs (line 186)

    pub async fn update_with_option(&mut self, stmt: Statement, options: QueryOptions) -> Result<i64, Status> {
        let request = ExecuteSqlRequest {
            session: self.get_session_name(),
            transaction: Some(self.transaction_selector.clone()),
            sql: stmt.sql.to_string(),
            params: Some(prost_types::Struct { fields: stmt.params }),
            param_types: stmt.param_types,
            resume_token: vec![],
            query_mode: options.mode.into(),
            partition_token: vec![],
            seqno: self.sequence_number.fetch_add(1, Ordering::Relaxed),
            query_options: options.optimizer_options,
            request_options: Transaction::create_request_options(options.call_options.priority),
        };

        let session = self.as_mut_session();
        let result = session
            .spanner_client
            .execute_sql(request, options.call_options.cancel, options.call_options.retry)
            .await;
        let response = session.invalidate_if_needed(result).await?;
        Ok(extract_row_count(response.into_inner().stats))
    }

src/session.rs (line 539)

async fn health_check(
    now: Instant,
    session_alive_trust_duration: Duration,
    sessions: &SessionPool,
    cancel: CancellationToken,
) {
    let sleep_duration = Duration::from_millis(10);
    loop {
        select! {
            _ = sleep(sleep_duration) => {},
            _ = cancel.cancelled() => break
        }
        let mut s = {
            // temporary take
            let mut locked = sessions.inner.lock();
            match locked.take() {
                Some(mut s) => {
                    // all the session check complete.
                    if s.last_checked_at == now {
                        locked.release(s);
                        break;
                    }
                    if std::cmp::max(s.last_used_at, s.last_pong_at) + session_alive_trust_duration >= now {
                        s.last_checked_at = now;
                        locked.release(s);
                        continue;
                    }
                    s
                }
                None => break,
            }
        };

        let request = ping_query_request(s.session.name.clone());
        match s.spanner_client.execute_sql(request, None, None).await {
            Ok(_) => {
                s.last_checked_at = now;
                s.last_pong_at = now;
                sessions.recycle(s);
            }
            Err(_) => {
                delete_session(&mut s).await;
                s.valid = false;
                sessions.recycle(s);
            }
        }
    }
}

pub async fn execute_streaming_sql(
    &mut self,
    req: ExecuteSqlRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<Streaming<PartialResultSet>>, Status>

execute_streaming_sql like ExecuteSql, except returns the result set as a stream. Unlike ExecuteSql, there is no limit on the size of the returned result set. However, no individual row in the result set can exceed 100 MiB, and no column value can exceed 10 MiB.

Examples found in repository

src/reader.rs (line 48)

    async fn read(
        &self,
        session: &mut SessionHandle,
        option: Option<CallOptions>,
    ) -> Result<Response<Streaming<PartialResultSet>>, Status> {
        let option = option.unwrap_or_default();
        let client = &mut session.spanner_client;
        let result = client
            .execute_streaming_sql(self.request.clone(), option.cancel, option.retry)
            .await;
        return session.invalidate_if_needed(result).await;
    }

pub async fn execute_batch_dml(
    &mut self,
    req: ExecuteBatchDmlRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<ExecuteBatchDmlResponse>, Status>

execute_batch_dml executes a batch of SQL DML statements. This method allows many statements to be run with lower latency than submitting them sequentially with ExecuteSql.

Statements are executed in sequential order. A request can succeed even if a statement fails. The ExecuteBatchDmlResponse.status field in the response provides information about the statement that failed. Clients must inspect this field to determine whether an error occurred.

Execution stops after the first failed statement; the remaining statements are not executed.

Examples found in repository

src/transaction_rw.rs (line 219)

    pub async fn batch_update_with_option(
        &mut self,
        stmt: Vec<Statement>,
        options: QueryOptions,
    ) -> Result<Vec<i64>, Status> {
        let request = ExecuteBatchDmlRequest {
            session: self.get_session_name(),
            transaction: Some(self.transaction_selector.clone()),
            seqno: self.sequence_number.fetch_add(1, Ordering::Relaxed),
            request_options: Transaction::create_request_options(options.call_options.priority),
            statements: stmt
                .into_iter()
                .map(|x| execute_batch_dml_request::Statement {
                    sql: x.sql,
                    params: Some(Struct { fields: x.params }),
                    param_types: x.param_types,
                })
                .collect(),
        };

        let session = self.as_mut_session();
        let result = session
            .spanner_client
            .execute_batch_dml(request, options.call_options.cancel, options.call_options.retry)
            .await;
        let response = session.invalidate_if_needed(result).await?;
        Ok(response
            .into_inner()
            .result_sets
            .into_iter()
            .map(|x| extract_row_count(x.stats))
            .collect())
    }

pub async fn read(
    &mut self,
    req: ReadRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<ResultSet>, Status>

read reads rows from the database using key lookups and scans, as a simple key/value style alternative to ExecuteSql. This method cannot be used to return a result set larger than 10 MiB; if the read matches more data than that, the read fails with a FAILED_PRECONDITION error.

Reads inside read-write transactions might return ABORTED. If this occurs, the application should restart the transaction from the beginning. See Transaction for more details.

Larger result sets can be yielded in streaming fashion by calling StreamingRead instead.

pub async fn streaming_read(
    &mut self,
    req: ReadRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<Streaming<PartialResultSet>>, Status>

streaming_read like read, except returns the result set as a stream. Unlike read, there is no limit on the size of the returned result set. However, no individual row in the result set can exceed 100 MiB, and no column value can exceed 10 MiB.

Examples found in repository

src/reader.rs (line 76)

    async fn read(
        &self,
        session: &mut SessionHandle,
        option: Option<CallOptions>,
    ) -> Result<Response<Streaming<PartialResultSet>>, Status> {
        let option = option.unwrap_or_default();
        let client = &mut session.spanner_client;
        let result = client
            .streaming_read(self.request.clone(), option.cancel, option.retry)
            .await;
        return session.invalidate_if_needed(result).await;
    }

pub async fn begin_transaction(
    &mut self,
    req: BeginTransactionRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<Transaction>, Status>

BeginTransaction begins a new transaction. This step can often be skipped: Read, ExecuteSql and Commit can begin a new transaction as a side-effect.

Examples found in repository

src/transaction_rw.rs (line 138)

    async fn begin_internal(
        mut session: ManagedSession,
        mode: transaction_options::Mode,
        options: CallOptions,
    ) -> Result<ReadWriteTransaction, BeginError> {
        let request = BeginTransactionRequest {
            session: session.session.name.to_string(),
            options: Some(TransactionOptions { mode: Some(mode) }),
            request_options: Transaction::create_request_options(options.priority),
        };
        let result = session
            .spanner_client
            .begin_transaction(request, options.cancel, options.retry)
            .await;
        let response = match session.invalidate_if_needed(result).await {
            Ok(response) => response,
            Err(err) => {
                return Err(BeginError { status: err, session });
            }
        };
        let tx = response.into_inner();
        Ok(ReadWriteTransaction {
            base_tx: Transaction {
                session: Some(session),
                sequence_number: AtomicI64::new(0),
                transaction_selector: TransactionSelector {
                    selector: Some(transaction_selector::Selector::Id(tx.id.clone())),
                },
            },
            tx_id: tx.id,
            wb: vec![],
        })
    }

src/transaction_ro.rs (line 84)

    pub async fn begin(
        mut session: ManagedSession,
        tb: TimestampBound,
        options: CallOptions,
    ) -> Result<ReadOnlyTransaction, Status> {
        let request = BeginTransactionRequest {
            session: session.session.name.to_string(),
            options: Some(TransactionOptions {
                mode: Some(transaction_options::Mode::ReadOnly(tb.into())),
            }),
            request_options: Transaction::create_request_options(options.priority),
        };

        let result = session
            .spanner_client
            .begin_transaction(request, options.cancel, options.retry)
            .await;
        match session.invalidate_if_needed(result).await {
            Ok(response) => {
                let tx = response.into_inner();
                let rts = tx.read_timestamp.unwrap();
                let st: SystemTime = rts.try_into().unwrap();
                Ok(ReadOnlyTransaction {
                    base_tx: Transaction {
                        session: Some(session),
                        sequence_number: AtomicI64::new(0),
                        transaction_selector: TransactionSelector {
                            selector: Some(transaction_selector::Selector::Id(tx.id)),
                        },
                    },
                    rts: Some(OffsetDateTime::from(st)),
                })
            }
            Err(e) => Err(e),
        }
    }

pub async fn commit(
    &mut self,
    req: CommitRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<CommitResponse>, Status>

Commit commits a transaction. The request includes the mutations to be applied to rows in the database.

Commit might return an ABORTED error. This can occur at any time; commonly, the cause is conflicts with concurrent transactions. However, it can also happen for a variety of other reasons. If Commit returns ABORTED, the caller should re-attempt the transaction from the beginning, re-using the same session.

On very rare occasions, Commit might return UNKNOWN. This can happen, for example, if the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost track of the transaction outcome and we recommend that you perform another read from the database to see the state of things as they are now.

Examples found in repository

src/transaction_rw.rs (line 339)

pub(crate) async fn commit(
    session: &mut ManagedSession,
    ms: Vec<Mutation>,
    tx: commit_request::Transaction,
    commit_options: CommitOptions,
) -> Result<CommitResponse, Status> {
    let request = CommitRequest {
        session: session.session.name.to_string(),
        mutations: ms,
        transaction: Some(tx),
        request_options: Transaction::create_request_options(commit_options.call_options.priority),
        return_commit_stats: commit_options.return_commit_stats,
    };
    let result = session
        .spanner_client
        .commit(request, commit_options.call_options.cancel, commit_options.call_options.retry)
        .await;
    let response = session.invalidate_if_needed(result).await;
    match response {
        Ok(r) => Ok(r.into_inner()),
        Err(s) => Err(s),
    }
}

pub async fn rollback(
    &mut self,
    req: RollbackRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<()>, Status>

Rollback rolls back a transaction, releasing any locks it holds. It is a good idea to call this for any transaction that includes one or more Read or ExecuteSql requests and ultimately decides not to commit.

Rollback returns OK if it successfully aborts the transaction, the transaction was already aborted, or the transaction is not found. Rollback never returns ABORTED.

Examples found in repository

src/transaction_rw.rs (line 318)

    pub(crate) async fn rollback(
        &mut self,
        cancel: Option<CancellationToken>,
        retry: Option<RetrySetting>,
    ) -> Result<(), Status> {
        let request = RollbackRequest {
            transaction_id: self.tx_id.clone(),
            session: self.get_session_name(),
        };
        let session = self.as_mut_session();
        let result = session.spanner_client.rollback(request, cancel, retry).await;
        session.invalidate_if_needed(result).await?.into_inner();
        Ok(())
    }

pub async fn partition_query(
    &mut self,
    req: PartitionQueryRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<PartitionResponse>, Status>

PartitionQuery creates a set of partition tokens that can be used to execute a query operation in parallel. Each of the returned partition tokens can be used by ExecuteStreamingSql to specify a subset of the query result to read. The same session and read-only transaction must be used by the PartitionQueryRequest used to create the partition tokens and the ExecuteSqlRequests that use the partition tokens.

Partition tokens become invalid when the session used to create them is deleted, is idle for too long, begins a new transaction, or becomes too old. When any of these happen, it is not possible to resume the query, and the whole operation must be restarted from the beginning.

Examples found in repository

src/transaction_ro.rs (line 239)

    pub async fn partition_query_with_option(
        &mut self,
        stmt: Statement,
        po: Option<PartitionOptions>,
        qo: QueryOptions,
    ) -> Result<Vec<Partition<StatementReader>>, Status> {
        let request = PartitionQueryRequest {
            session: self.get_session_name(),
            transaction: Some(self.transaction_selector.clone()),
            sql: stmt.sql.clone(),
            params: Some(prost_types::Struct {
                fields: stmt.params.clone(),
            }),
            param_types: stmt.param_types.clone(),
            partition_options: po,
        };
        let result = match self
            .as_mut_session()
            .spanner_client
            .partition_query(request.clone(), qo.call_options.cancel.clone(), qo.call_options.retry.clone())
            .await
        {
            Ok(r) => Ok(r
                .into_inner()
                .partitions
                .into_iter()
                .map(|x| Partition {
                    reader: StatementReader {
                        request: ExecuteSqlRequest {
                            session: self.get_session_name(),
                            transaction: Some(self.transaction_selector.clone()),
                            sql: stmt.sql.clone(),
                            params: Some(prost_types::Struct {
                                fields: stmt.params.clone(),
                            }),
                            param_types: stmt.param_types.clone(),
                            resume_token: vec![],
                            query_mode: 0,
                            partition_token: x.partition_token,
                            seqno: 0,
                            query_options: qo.optimizer_options.clone(),
                            request_options: Transaction::create_request_options(qo.call_options.priority),
                        },
                    },
                })
                .collect()),
            Err(e) => Err(e),
        };
        self.as_mut_session().invalidate_if_needed(result).await
    }

pub async fn partition_read(
    &mut self,
    req: PartitionReadRequest,
    cancel: Option<CancellationToken>,
    retry: Option<RetrySetting>
) -> Result<Response<PartitionResponse>, Status>

PartitionRead creates a set of partition tokens that can be used to execute a read operation in parallel. Each of the returned partition tokens can be used by StreamingRead to specify a subset of the read result to read. The same session and read-only transaction must be used by the PartitionReadRequest used to create the partition tokens and the ReadRequests that use the partition tokens. There are no ordering guarantees on rows returned among the returned partition tokens, or even within each individual StreamingRead call issued with a partition_token.

Partition tokens become invalid when the session used to create them is deleted, is idle for too long, begins a new transaction, or becomes too old. When any of these happen, it is not possible to resume the read, and the whole operation must be restarted from the beginning.

Examples found in repository

src/transaction_ro.rs (line 184)

    pub async fn partition_read_with_option(
        &mut self,
        table: &str,
        columns: &[&str],
        keys: impl Into<KeySet> + Clone,
        po: Option<PartitionOptions>,
        ro: ReadOptions,
    ) -> Result<Vec<Partition<TableReader>>, Status> {
        let columns: Vec<String> = columns.iter().map(|x| x.to_string()).collect();
        let inner_keyset = keys.into().inner;
        let request = PartitionReadRequest {
            session: self.get_session_name(),
            transaction: Some(self.transaction_selector.clone()),
            table: table.to_string(),
            index: ro.index.clone(),
            columns: columns.clone(),
            key_set: Some(inner_keyset.clone()),
            partition_options: po,
        };
        let result = match self
            .as_mut_session()
            .spanner_client
            .partition_read(request, ro.call_options.cancel, ro.call_options.retry)
            .await
        {
            Ok(r) => Ok(r
                .into_inner()
                .partitions
                .into_iter()
                .map(|x| Partition {
                    reader: TableReader {
                        request: ReadRequest {
                            session: self.get_session_name(),
                            transaction: Some(self.transaction_selector.clone()),
                            table: table.to_string(),
                            index: ro.index.clone(),
                            columns: columns.clone(),
                            key_set: Some(inner_keyset.clone()),
                            limit: ro.limit,
                            resume_token: vec![],
                            partition_token: x.partition_token,
                            request_options: Transaction::create_request_options(ro.call_options.priority),
                        },
                    },
                })
                .collect()),
            Err(e) => Err(e),
        };
        self.as_mut_session().invalidate_if_needed(result).await
    }

Trait Implementations

impl Clone for Client

fn clone(&self) -> Client

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.