Temporal Rust Client

This crate provides a Rust client for interacting with the Temporal service. It can be used standalone to start and manage workflows, or together with the temporalio-sdk crate to run workers.

⚠️ This crate is in Public Preview and under active development. The API can and will continue to evolve.

Quick Start

Connecting and Starting Workflows with Environment Configuration

The simplest way to connect is to load connection settings from environment variables and/or a temporal.toml config file:

use temporalio_client::{
    Client, Connection, WorkflowOptions, GetWorkflowResultOptions,
    envconfig::LoadClientConfigProfileOptions,
};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (conn_options, client_options) = ClientOptions::load_from_config(
        LoadClientConfigProfileOptions::default()
    )?;

    let connection = Connection::connect(conn_options).await?;
    let client = Client::new(connection, client_options);

    // Start a workflow
    let handle = client.start_workflow(
        GreetingWorkflow::run,
        "World".to_string(),
        WorkflowOptions::new("my-task-queue", "greeting-workflow-1").build()
    ).await?;

    // Wait for the result
    let result = handle.get_result(GetWorkflowResultOptions::default()).await?;
    Ok(())
}

This reads TEMPORAL_ADDRESS, TEMPORAL_NAMESPACE, TEMPORAL_API_KEY, TLS settings, and more from the environment. See the envconfig module docs for the full list of supported variables and the TOML file format.

Connecting and Starting Workflows with Explicit Options

use temporalio_client::{
    Client, ClientOptions, Connection, ConnectionOptions,
    WorkflowOptions, GetWorkflowResultOptions, Url,
};
use std::str::FromStr;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let connection = Connection::connect(
        ConnectionOptions::new(Url::from_str("http://localhost:7233")?)
            .identity("my-client".to_string())
            .build()
    ).await?;

    // "default" is your namespace
    let client = Client::new(connection, ClientOptions::new("default").build());

    // Start a workflow
    let handle = client.start_workflow(
        GreetingWorkflow::run,
        "World".to_string(),
        WorkflowOptions::new("my-task-queue", "greeting-workflow-1").build()
    ).await?;

    // Wait for the result
    let result = handle.get_result(GetWorkflowResultOptions::default()).await?;

    Ok(())
}

Signals, Queries, and Updates

Once you have a workflow handle, you can interact with the running workflow:

use temporalio_client::{
    SignalOptions, QueryOptions, UpdateOptions,
    StartUpdateOptions,
    UntypedSignal,
};
use temporalio_common::data_converters::{PayloadConverter, RawValue};

// Get a handle to an existing workflow (or use one from start_workflow)
let handle = client.get_workflow_handle::<MyWorkflow>("workflow-id");

// --- Signals (fire-and-forget messages) ---
handle.signal(MyWorkflow::push_value, 42, SignalOptions::default()).await?;

// --- Queries (read workflow state) ---
let values = handle
    .query(MyWorkflow::get_values, (), QueryOptions::default())
    .await?;

// --- Updates (modify state and get a result) ---
let values = handle
    .execute_update(MyWorkflow::add_wait_return, 100, UpdateOptions::default())
    .await?;

// Start an update and wait for acceptance only
let update_handle = handle
    .start_update(
        MyWorkflow::add_wait_return,
        50,
        StartUpdateOptions::default()
    )
    .await?;
update_handle.get_result().await?;

// --- Untyped interactions (when types aren't known at compile time) ---
let pc = PayloadConverter::serde_json();
handle
    .signal(
        UntypedSignal::new("increment"),
        RawValue::from_value(&25i32, &pc),
        SignalOptions::default(),
    )
    .await?;
// UntypedQuery and UntypedUpdate work similarly

Cancelling and Terminating Workflows

use temporalio_client::{CancelWorkflowOptions, TerminateWorkflowOptions};

// Request cancellation (workflow can handle this gracefully)
handle.cancel(CancelWorkflowOptions::builder().reason("No longer needed").build()).await?;

// Terminate immediately (workflow cannot intercept this)
handle.terminate(TerminateWorkflowOptions::builder().reason("Emergency shutdown").build()).await?;

Listing Workflows

use temporalio_client::ListWorkflowsOptions;
use futures_util::StreamExt;

let mut stream = client.list_workflows(
    "WorkflowType = 'GreetingWorkflow'",
    ListWorkflowsOptions::builder().limit(10).build()
);

while let Some(result) = stream.next().await {
    let execution = result?;
    println!("Workflow: {} ({})", execution.id(), execution.workflow_type());
}

Raw gRPC Access

For operations not covered by the high-level API, access the underlying gRPC service clients directly:

let mut workflowf_service = client.connection().workflow_service();
let mut operator_service = client.connection().operator_service();