@langchain/langgraph
Version:
LangGraph
91 lines • 3.73 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.interrupt = interrupt;
const singletons_1 = require("@langchain/core/singletons");
const errors_js_1 = require("./errors.cjs");
const constants_js_1 = require("./constants.cjs");
/**
* Interrupts the execution of a graph node.
* This function can be used to pause execution of a node, and return the value of the `resume`
* input when the graph is re-invoked using `Command`.
* Multiple interrupts can be called within a single node, and each will be handled sequentially.
*
* When an interrupt is called:
* 1. If there's a `resume` value available (from a previous `Command`), it returns that value.
* 2. Otherwise, it throws a `GraphInterrupt` with the provided value
* 3. The graph can be resumed by passing a `Command` with a `resume` value
*
* Because the `interrupt` function propagates by throwing a special `GraphInterrupt` error,
* you should avoid using `try/catch` blocks around the `interrupt` function,
* or if you do, ensure that the `GraphInterrupt` error is thrown again within your `catch` block.
*
* @param value - The value to include in the interrupt. This will be available in task.interrupts[].value
* @returns The `resume` value provided when the graph is re-invoked with a Command
*
* @example
* ```typescript
* // Define a node that uses multiple interrupts
* const nodeWithInterrupts = () => {
* // First interrupt - will pause execution and include {value: 1} in task values
* const answer1 = interrupt({ value: 1 });
*
* // Second interrupt - only called after first interrupt is resumed
* const answer2 = interrupt({ value: 2 });
*
* // Use the resume values
* return { myKey: answer1 + " " + answer2 };
* };
*
* // Resume the graph after first interrupt
* await graph.stream(new Command({ resume: "answer 1" }));
*
* // Resume the graph after second interrupt
* await graph.stream(new Command({ resume: "answer 2" }));
* // Final result: { myKey: "answer 1 answer 2" }
* ```
*
* @throws {Error} If called outside the context of a graph
* @throws {GraphInterrupt} When no resume value is available
*/
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function interrupt(value) {
const config = singletons_1.AsyncLocalStorageProviderSingleton.getRunnableConfig();
if (!config) {
throw new Error("Called interrupt() outside the context of a graph.");
}
const conf = config.configurable;
if (!conf) {
throw new Error("No configurable found in config");
}
// Track interrupt index
const scratchpad = conf[constants_js_1.CONFIG_KEY_SCRATCHPAD];
scratchpad.interruptCounter += 1;
const idx = scratchpad.interruptCounter;
// Find previous resume values
if (scratchpad.resume.length > 0 && idx < scratchpad.resume.length) {
return scratchpad.resume[idx];
}
// Find current resume value
if (scratchpad.nullResume !== undefined) {
if (scratchpad.resume.length !== idx) {
throw new Error(`Resume length mismatch: ${scratchpad.resume.length} !== ${idx}`);
}
const v = scratchpad.consumeNullResume();
scratchpad.resume.push(v);
const send = conf[constants_js_1.CONFIG_KEY_SEND];
if (send) {
send([[constants_js_1.RESUME, scratchpad.resume]]);
}
return v;
}
// No resume value found
throw new errors_js_1.GraphInterrupt([
{
value,
when: "during",
resumable: true,
ns: conf[constants_js_1.CONFIG_KEY_CHECKPOINT_NS]?.split(constants_js_1.CHECKPOINT_NAMESPACE_SEPARATOR),
},
]);
}
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