improve(logs): format logs in logfmt to make querying easier in Loki

sdnts · Sep 15, 2023 · 6b42f04 · 6b42f04
1 parent c7276e8
commit 6b42f04
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Showing 2 changed files with 33 additions and 20 deletions.
diff --git a/src/endpoints/logs.ts b/src/endpoints/logs.ts
@@ -65,8 +65,27 @@ export const endpoint: Endpoint<typeof schema> = {
             if (l.timestamp.p === "ms")
               l.timestamp.v = `${l.timestamp.v}000000`;
 
-            if (!l.kv && !params.data.kv) return [l.timestamp.v, l.message];
-            return [l.timestamp.v, l.message, { ...params.data.kv, ...l.kv }];
+            // Loki supports structured metadata that is supposed to be treated
+            // as labels, but it is experimental and doesn't seem to be working.
+            // Specifically, I don't see these structured metadata labels and
+            // cannot query using them.
+            // So instead I'll send a logfmt-style string as the message instead,
+            // which will let me use the `logfmt` stream processor.
+            // JSON is another option but stringified JSON be ugly.
+            // Reference: https://grafana.com/docs/loki/latest/get-started/labels/structured-metadata/
+            // TODO: We should just use structured metadata once it lands as stable
+
+            const log = Object.entries({
+              ...params.data.kv,
+              ...l.kv,
+              msg: l.message,
+            })
+              .map(([k, v]) => {
+                if (typeof v === "string") return `${k}="${v}"`;
+                return `${k}=${v}`;
+              })
+              .join(" ");
+            return [l.timestamp.v, log];
           }),
         };
       }),

diff --git a/tests/ingest.test.ts b/tests/ingest.test.ts
@@ -288,7 +288,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "info",
             },
-            values: [["001000000", "Incoming request"]],
+            values: [["001000000", 'msg="Incoming request"']],
           },
         ],
       }),
@@ -326,7 +326,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "fatal",
             },
-            values: [["001000000", "Incoming request"]],
+            values: [["001000000", 'msg="Incoming request"']],
           },
         ],
       }),
@@ -363,7 +363,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "info",
             },
-            values: [["001000000", "Incoming request"]],
+            values: [["001000000", 'msg="Incoming request"']],
           },
         ],
       }),
@@ -400,7 +400,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "info",
             },
-            values: [["001", "Incoming request"]],
+            values: [["001", 'msg="Incoming request"']],
           },
         ],
       }),
@@ -437,7 +437,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "info",
             },
-            values: [["001", "Incoming request"]],
+            values: [["001", 'msg="Incoming request"']],
           },
         ],
       }),
@@ -475,7 +475,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "info",
             },
-            values: [["001", "Incoming request", { method: "GET" }]],
+            values: [["001", 'method="GET" msg="Incoming request"']],
           },
         ],
       }),
@@ -513,7 +513,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "info",
             },
-            values: [["001", "Incoming request", { rayId: "1234" }]],
+            values: [["001", 'rayId="1234" msg="Incoming request"']],
           },
         ],
       }),
@@ -553,7 +553,7 @@ test.describe("logs", async () => {
               level: "info",
             },
             values: [
-              ["001", "Incoming request", { rayId: "1234", method: "GET" }],
+              ["001", 'rayId="1234" method="GET" msg="Incoming request"'],
             ],
           },
         ],
@@ -611,14 +611,9 @@ test.describe("logs", async () => {
             values: [
               [
                 "001000000",
-                "Incoming request",
-                {
-                  rayId: "abcd",
-                  method: "GET",
-                  path: "/tunnel",
-                },
+                'rayId="abcd" method="GET" path="/tunnel" msg="Incoming request"',
               ],
-              ["004000000", "Response", { rayId: "abcd", status: 200 }],
+              ["004000000", 'rayId="abcd" status=200 msg="Response"'],
             ],
           },
           {
@@ -630,8 +625,7 @@ test.describe("logs", async () => {
             values: [
               [
                 "002000000",
-                "Forwarding to DO",
-                { rayId: "abcd", tunnelId: "1234" },
+                'rayId="abcd" tunnelId="1234" msg="Forwarding to DO"',
               ],
             ],
           },
@@ -641,7 +635,7 @@ test.describe("logs", async () => {
               origin: "https://blob.city",
               level: "trace",
             },
-            values: [["003", "Creating WebSocketPair", { rayId: "abcd" }]],
+            values: [["003", 'rayId="abcd" msg="Creating WebSocketPair"']],
           },
         ],
       }),