Method queryLokiRange

backend/src/trace/log-stream.service.ts:281–350

(
    selector: string,
    limit: number,
    cursor?: string,
  )

  }

  private async queryLokiRange(
    selector: string,
    limit: number,
    cursor?: string,
  ): Promise<LokiEntry[]> {
    const params = new URLSearchParams({
      query: selector,
      direction: 'backward', // Most recent first
      limit: limit.toString(),
    });

    if (cursor) {
      // End time is the cursor (exclusive)
      params.set('end', this.toNanoseconds(new Date(cursor)));
    }

    const url = this.resolveUrl(`/loki/api/v1/query_range?${params.toString()}`);
    console.log(`[LogStreamService] Querying Loki: ${url}`);

    const response = await fetch(url, {
      method: 'GET',
      headers: this.buildHeaders(),
    });

    if (!response.ok) {
      const errorText = await response.text();
      console.error(
        `[LogStreamService] Loki query failed: ${response.status} ${response.statusText} - ${errorText}`,
      );
      throw new ServiceUnavailableException(
        `Loki query failed: ${response.status} ${response.statusText} - ${errorText}`,
      );
    }

    const payload = (await response.json()) as {
      data?: {
        result?: {
          stream?: Record<string, string>;
          values?: [string, string][];
        }[];
      };
    };

    console.log(
      `[LogStreamService] Loki response: ${JSON.stringify({
        resultCount: payload.data?.result?.length ?? 0,
        totalValues:
          payload.data?.result?.reduce((sum, r) => sum + (r.values?.length ?? 0), 0) ?? 0,
      })}`,
    );

    const entries: LokiEntry[] = [];
    const results = payload.data?.result ?? [];
    for (const result of results) {
      const streamLabels = result.stream ?? {};
      for (const [timestamp, message] of result.values ?? []) {
        entries.push({
          timestamp: this.fromNanoseconds(timestamp),