Enhancement: fallback for missing si network stats (#6367)

docs/widgets/info/resources.md

@@ -7,13 +7,17 @@ You can include all or some of the available resources. If you do not want to se
 
 The disk path is the path reported by `df` (Mounted On), or the mount point of the disk.
 
+!!! note
+
+    Any disk you wish to access must be mounted to your container as a volume.
+
 The cpu and memory resource information are the container's usage while [glances](glances.md) displays statistics for the host machine on which it is installed.
 
 The resources widget primarily relies on a popular tool called [systeminformation](https://systeminformation.io). Thus, any limitiations of that software apply, for example, BRTFS RAID is not supported for the disk usage. In this case users may want to use the [glances widget](glances.md) instead.
 
-_Note: unfortunately, the package used for getting CPU temp ([systeminformation](https://systeminformation.io)) is not compatible with some setups and will not report any value(s) for CPU temp._
+!!! warning
 
-**Any disk you wish to access must be mounted to your container as a volume.**
+    The package used for getting CPU temp ([systeminformation](https://systeminformation.io)) is not compatible with some setups and will not report any value(s) for CPU temp.
 
 ```yaml
 - resources:
@@ -75,3 +79,10 @@ You can additionally supply an optional `expanded` property set to true in order
 ```
 
 ![194136533-c4238c82-4d67-41a4-b3c8-18bf26d33ac2](https://user-images.githubusercontent.com/3441425/194728642-a9885274-922b-4027-acf5-a746f58fdfce.png)
+
+To monitor a named host network interface in Docker (for example `network: eno1`), mount host `/sys` (read-only):
+
+```yaml
+volumes:
+  - /sys:/sys:ro
+```

src/__tests__/pages/api/widgets/resources.test.js

@@ -90,17 +90,74 @@ describe("pages/api/widgets/resources", () => {
   });
 
   it("returns 404 when requested network interface does not exist", async () => {
-    si.networkStats.mockResolvedValueOnce([{ iface: "en0" }]);
+    si.networkStats.mockResolvedValueOnce([{ iface: "en0" }]).mockResolvedValueOnce([
+      {
+        iface: "missing",
+        operstate: "unknown",
+        rx_bytes: 0,
+        rx_dropped: 0,
+        rx_errors: 0,
+        tx_bytes: 0,
+        tx_dropped: 0,
+        tx_errors: 0,
+        rx_sec: null,
+        tx_sec: null,
+        ms: 0,
+      },
+    ]);
 
     const req = { query: { type: "network", interfaceName: "missing" } };
     const res = createMockRes();
 
     await handler(req, res);
 
+    expect(si.networkStats).toHaveBeenNthCalledWith(1, "*");
+    expect(si.networkStats).toHaveBeenNthCalledWith(2, "missing");
     expect(res.statusCode).toBe(404);
     expect(res.body).toEqual({ error: "Interface not found" });
   });
 
+  it("falls back to direct named interface query when wildcard enumeration misses it", async () => {
+    si.networkStats.mockResolvedValueOnce([{ iface: "eth0", rx_bytes: 1 }]).mockResolvedValueOnce([
+      {
+        iface: "eno1",
+        operstate: "up",
+        rx_bytes: 1000,
+        rx_dropped: 0,
+        rx_errors: 0,
+        tx_bytes: 500,
+        tx_dropped: 0,
+        tx_errors: 0,
+        rx_sec: null,
+        tx_sec: null,
+        ms: 0,
+      },
+    ]);
+
+    const req = { query: { type: "network", interfaceName: "eno1" } };
+    const res = createMockRes();
+
+    await handler(req, res);
+
+    expect(si.networkStats).toHaveBeenNthCalledWith(1, "*");
+    expect(si.networkStats).toHaveBeenNthCalledWith(2, "eno1");
+    expect(res.statusCode).toBe(200);
+    expect(res.body.interface).toBe("eno1");
+    expect(res.body.network).toEqual({
+      iface: "eno1",
+      operstate: "up",
+      rx_bytes: 1000,
+      rx_dropped: 0,
+      rx_errors: 0,
+      tx_bytes: 500,
+      tx_dropped: 0,
+      tx_errors: 0,
+      rx_sec: null,
+      tx_sec: null,
+      ms: 0,
+    });
+  });
+
   it("returns default interface network stats", async () => {
     si.networkStats.mockResolvedValueOnce([{ iface: "en0", rx_bytes: 1 }]);
     si.networkInterfaceDefault.mockResolvedValueOnce("en0");

src/pages/api/widgets/resources.js

@@ -4,6 +4,21 @@ import createLogger from "utils/logger";
 
 const logger = createLogger("resources");
 
+function isMissingNetworkStat(networkData, interfaceName) {
+  return (
+    networkData.operstate === "unknown" &&
+    networkData.rx_bytes === 0 &&
+    networkData.rx_dropped === 0 &&
+    networkData.rx_errors === 0 &&
+    networkData.tx_bytes === 0 &&
+    networkData.tx_dropped === 0 &&
+    networkData.tx_errors === 0 &&
+    networkData.rx_sec === null &&
+    networkData.tx_sec === null &&
+    networkData.ms === 0
+  );
+}
+
 export default async function handler(req, res) {
   const { type, target, interfaceName = "default" } = req.query;
 
@@ -64,6 +79,17 @@ export default async function handler(req, res) {
     logger.debug("networkData:", JSON.stringify(networkData));
     if (interfaceName && interfaceName !== "default") {
       networkData = networkData.filter((network) => network.iface === interfaceName).at(0);
+      if (!networkData) {
+        // Fallback for e.g. docker where networkStats("*") may not return stats for host interfaces
+        const directNetworkData = await si.networkStats(interfaceName);
+        logger.debug("directNetworkData:", JSON.stringify(directNetworkData));
+        networkData = Array.isArray(directNetworkData) ? directNetworkData.at(0) : null;
+
+        // si returns unknown + zeroes when interface truly does not exist
+        if (!networkData || isMissingNetworkStat(networkData, interfaceName)) {
+          networkData = null;
+        }
+      }
       if (!networkData) {
         return res.status(404).json({
           error: "Interface not found",