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Copy pathheart.ts
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82 lines (73 loc) · 2.12 KB
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import { logger } from "@coder/logger"
import { promises as fs } from "fs"
import { Emitter } from "../common/emitter"
/**
* Provides a heartbeat using a local file to indicate activity.
*/
export class Heart {
private heartbeatTimer?: NodeJS.Timeout
private heartbeatInterval = 60000
public lastHeartbeat = 0
private readonly _onChange = new Emitter<"alive" | "expired" | "unknown">()
readonly onChange = this._onChange.event
private state: "alive" | "expired" | "unknown" = "expired"
public constructor(
private readonly heartbeatPath: string,
private readonly isActive: () => Promise<boolean>,
) {
this.beat = this.beat.bind(this)
this.alive = this.alive.bind(this)
}
private setState(state: typeof this.state) {
if (this.state !== state) {
this.state = state
this._onChange.emit(this.state)
}
}
public alive(): boolean {
const now = Date.now()
return now - this.lastHeartbeat < this.heartbeatInterval
}
/**
* Write to the heartbeat file if we haven't already done so within the
* timeout and start or reset a timer that keeps running as long as there is
* activity. Failures are logged as warnings.
*/
public async beat(): Promise<void> {
if (this.alive()) {
this.setState("alive")
return
}
logger.debug("heartbeat")
this.lastHeartbeat = Date.now()
if (typeof this.heartbeatTimer !== "undefined") {
clearTimeout(this.heartbeatTimer)
}
this.heartbeatTimer = setTimeout(async () => {
try {
if (await this.isActive()) {
this.beat()
} else {
this.setState("expired")
}
} catch (error: unknown) {
logger.warn((error as Error).message)
this.setState("unknown")
}
}, this.heartbeatInterval)
this.setState("alive")
try {
return await fs.writeFile(this.heartbeatPath, "")
} catch (error: any) {
logger.warn(error.message)
}
}
/**
* Call to clear any heartbeatTimer for shutdown.
*/
public dispose(): void {
if (typeof this.heartbeatTimer !== "undefined") {
clearTimeout(this.heartbeatTimer)
}
}
}