matrix-org · DMRobertson · Feb 1, 2023 · Jan 31, 2023 · Jan 31, 2023 · Jan 31, 2023
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+Add an [lnav](https://lnav.org) config file for Synapse logs to `/contrib/lnav`.
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+# `lnav` config for Synapse logs
+
+[lnav](https://lnav.org/) is a log-viewing tool. It is particularly useful when 
+you need to interleave multiple log files, or for exploring a large log file
+with regex filters. The downside is that it is not as ubiquitous as tools like
+`less`, `grep`, etc.
+
+This directory contains an `lnav` [log format definition](
+    https://docs.lnav.org/en/v0.10.1/formats.html#defining-a-new-format
+) for Synapse logs as
+emitted by Synapse with the default [logging configuration](
+    https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#log_config
+). It supports lnav 0.10.1 because that's what's packaged by my distribution.
+
+This should allow lnav:
+
+- to interpret timestamps, allowing log interleaving;
+- to interpret log severity levels, allowing colouring by log level(!!!);
+- to interpret request IDs, allowing you to skip through a specific request; and
+- to highlight room, event and user IDs in logs.
+
+See also https://gist.github.com/benje/e2ab750b0a81d11920d83af637d289f7 for a
+ similar example.
+
+## Example
+
+[![asciicast](https://asciinema.org/a/556133.svg)](https://asciinema.org/a/556133)
+
+## Tips
+
+- `lnav -i /path/to/synapse/checkout/contrib/lnav/synapse-log-format.json`
+- `lnav my_synapse_log_file` or `lnav synapse_log_files.*`, etc.
+- `lnav --help` for CLI help.
+
+Within lnav itself:
+
+- `?` for help within lnav itself.
+- `q` to quit.
+- `/` to search a-la `less` and `vim`, then `n` and `N` to continue searching 
+  down and up.
+- Use `o` and `O` to skip through logs based on the request ID (`POST-1234`, or
+  else the value of the [`request_id_header`](
+    https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html?highlight=request_id_header#listeners
+  ) header). This may get confused if the same request ID is repeated among 
+  multiple files or process restarts.
+- ???
+- Profit
@@ -0,0 +1,67 @@
+{
+  "$schema": "https://lnav.org/schemas/format-v1.schema.json",
+  "synapse": {
+    "title": "Synapse logs",
+    "description": "Logs output by Synapse, a Matrix homesever, under its default logging config.",
+    "regex": {
+      "log": {
+        "pattern": ".*(?<timestamp>\\d{4}-\\d{2}-\\d{2} \\d{2}:\\d{2}:\\d{2},\\d{3}) - (?<logger>.+) - (?<lineno>\\d+) - (?<level>\\w+) - (?<context>.+) - (?<body>.*)"
+      }
+    },
+    "json": false,
+    "timestamp-field": "timestamp",
+    "timestamp-format": [
+      "%Y-%m-%d %H:%M:%S,%L"
+    ],
+    "level-field": "level",
+    "body-field": "body",
+    "opid-field": "context",
+    "level": {
+      "critical": "CRITICAL",
+      "error": "ERROR",
+      "warning": "WARNING",
+      "info": "INFO",
+      "debug": "DEBUG"
+    },
+    "sample": [
+      {
+        "line": "my-matrix-server-generic-worker-4 | 2023-01-27 09:47:09,818 - synapse.replication.tcp.client - 381 - ERROR - PUT-32992 - Timed out waiting for stream receipts",
+        "level": "error"
+      },
+      {
+        "line": "my-matrix-server-federation-sender-1 | 2023-01-25 20:56:20,995 - synapse.http.matrixfederationclient - 709 - WARNING - federation_transaction_transmission_loop-3 - {PUT-O-3} [example.com] Request failed: PUT matrix://example.com/_matrix/federation/v1/send/1674680155797: HttpResponseException('403: Forbidden')",
+        "level": "warning"
+      },
+      {
+        "line": "my-matrix-server  | 2023-01-25 20:55:54,433 - synapse.storage.databases - 66 - INFO - main - [database config 'master']: Checking database server",
+        "level": "info"
+      },
+      {
+        "line": "my-matrix-server  | 2023-01-26 15:08:40,447 - synapse.access.http.8008 - 460 - INFO - PUT-74929 - 0.0.0.0 - 8008 - {@alice:example.com} Processed request: 0.011sec/0.000sec (0.000sec, 0.000sec) (0.001sec/0.008sec/3) 2B 200 \"PUT /_matrix/client/r0/user/%40alice%3Atexample.com/account_data/im.vector.setting.breadcrumbs HTTP/1.0\" \"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Element/1.11.20 Chrome/108.0.5359.179 Electron/22.0.3 Safari/537.36\" [0 dbevts]",
+        "level": "info"
+      }
+    ],
+    "highlights": {
+      "user_id": {
+        "pattern": "(@|%40)[^:% ]+(:|%3A)[\\[\\]0-9a-zA-Z.\\-:]+(:\\d{1,5})?(?<!:)",
+        "underline": true
+      },
+      "room_id": {
+        "pattern": "(!|%21)[^:% ]+(:|%3A)[\\[\\]0-9a-zA-Z.\\-:]+(:\\d{1,5})?(?<!:)",
+        "underline": true
+      },
+      "room_alias": {
+        "pattern": "(#|%23)[^:% ]+(:|%3A)[\\[\\]0-9a-zA-Z.\\-:]+(:\\d{1,5})?(?<!:)",
+        "underline": true
+      },
+      "event_id_v1_v2": {
+        "pattern": "(\\$|%25)[^:% ]+(:|%3A)[\\[\\]0-9a-zA-Z.\\-:]+(:\\d{1,5})?(?<!:)",
+        "underline": true
+      },
+      "event_id_v3_plus": {
+        "pattern": "(\\$|%25)([A-Za-z0-9+/_]|-){43}",
+        "underline": true
+      }
+    }
+  }
+}