InfraClaude

Instructions

Implementation Reference

• src/tools/prometheus/query.ts:29-74 (handler)

  The rangeQuery function handles the execution of Prometheus range queries, fetches data from the Prometheus API, and formats the result into a readable string.

  export async function rangeQuery(args: Record<string, unknown>): Promise<string> {
    const query = args.query as string;
    if (!query) throw new Error("PromQL query is required");
  
    const end = (args.end as string) || new Date().toISOString();
    const start = (args.start as string) || new Date(Date.now() - 3600000).toISOString();
    const step = (args.step as string) || "60s";
  
    const url = `${config.prometheusUrl}/api/v1/query_range?query=${encodeURIComponent(query)}&start=${encodeURIComponent(start)}&end=${encodeURIComponent(end)}&step=${encodeURIComponent(step)}`;
    const res = await fetch(url);
    if (!res.ok) throw new Error(`Prometheus range query failed: ${res.status}`);
  
    const data = (await res.json()) as { status: string; error?: string; data: { result: Array<{ metric: Record<string, string>; values: [number, string][] }> } };
    if (data.status !== "success") throw new Error(`Query error: ${data.error || "unknown"}`);
  
    const results = data.data.result || [];
    if (results.length === 0) return `No results for range query: ${query}`;
  
    const lines: string[] = [`Range query: ${query}`, `Period: ${start} → ${end} (step: ${step})`, ""];
  
    for (const r of results) {
      const labels = Object.entries(r.metric as Record<string, string>)
        .map(([k, v]) => `${k}="${v}"`)
        .join(", ");
      lines.push(`Metric: ${labels || "{}"}`);
  
      const values = (r.values as [number, string][]) || [];
      const first5 = values.slice(0, 5);
      const last5 = values.slice(-5);
  
      for (const [ts, val] of first5) {
        lines.push(`  ${new Date(ts * 1000).toISOString()} → ${val}`);
      }
      if (values.length > 10) {
        lines.push(`  ... (${values.length - 10} more data points) ...`);
      }
      if (values.length > 5) {
        for (const [ts, val] of last5) {
          lines.push(`  ${new Date(ts * 1000).toISOString()} → ${val}`);
        }
      }
      lines.push("");
    }
  
    return lines.join("\n");
  }

• src/tools/prometheus/index.ts:18-31 (registration)

  The MCP tool definition for 'prom_range_query', which defines its name, description, and input parameters.

  {
    name: "prom_range_query",
    description: "Execute a PromQL query over a time range and return series data",
    inputSchema: {
      type: "object" as const,
      properties: {
        query: { type: "string", description: "PromQL query expression" },
        start: { type: "string", description: "Start time (ISO 8601, default: 1h ago)" },
        end: { type: "string", description: "End time (ISO 8601, default: now)" },
        step: { type: "string", description: "Query step (e.g., '60s', '5m', default: '60s')" },
      },
      required: ["query"],
    },
  },