Method acquireConnection

src/node/runtime/SSH2ConnectionPool.ts:271–346

(
    config: SSHConnectionConfig,
    options: AcquireConnectionOptions = {}
  )

  private connections = new Map<string, SSH2ConnectionEntry>();

  async acquireConnection(
    config: SSHConnectionConfig,
    options: AcquireConnectionOptions = {}
  ): Promise<SSH2ConnectionEntry> {
    const key = makeConnectionKey(config);
    const timeoutMs = options.timeoutMs ?? DEFAULT_CONNECT_TIMEOUT_MS;
    const sleep = options.sleep ?? sleepWithAbort;
    const maxWaitMs = options.maxWaitMs ?? DEFAULT_SSH_MAX_WAIT_MS;
    const shouldWait = maxWaitMs > 0;
    const startTime = Date.now();

    while (true) {
      if (options.abortSignal?.aborted) {
        throw new Error(SSH2_OPERATION_ABORTED_ERROR);
      }

      const existing = this.connections.get(key);
      if (existing) {
        this.touchConnection(existing, key);
        this.markHealthy(config);
        return existing;
      }

      const health = this.health.get(key);
      if (health?.backoffUntil && health.backoffUntil > new Date()) {
        const remainingMs = health.backoffUntil.getTime() - Date.now();
        const remainingSecs = Math.ceil(remainingMs / 1000);

        if (!shouldWait) {
          throw new Error(
            `SSH connection to ${config.host} is in backoff for ${remainingSecs}s. ` +
              `Last error: ${health.lastError ?? "unknown"}`
          );
        }

        const elapsedMs = Date.now() - startTime;
        const budgetMs = Math.max(0, maxWaitMs - elapsedMs);
        if (budgetMs <= 0) {
          throw new Error(
            `SSH connection to ${config.host} is in backoff and maxWaitMs exceeded. ` +
              `Last error: ${health.lastError ?? "unknown"}`
          );
        }

        const waitMs = Math.min(remainingMs, budgetMs);
        options.onWait?.(waitMs);
        await sleep(waitMs, options.abortSignal);
        continue;
      }

      let inflight = this.inflight.get(key);
      if (!inflight) {
        inflight = this.connect(config, timeoutMs, options.abortSignal);
        this.inflight.set(key, inflight);
        // Attach no-op catch to prevent unhandled rejection when singleflighted
        // promise rejects before any caller awaits it. Actual errors are
        // propagated to callers via the await below.
        // eslint-disable-next-line @typescript-eslint/no-empty-function