| # Access log report |
|
|
| `logs/access.log` is a web server access log in a combined-ish format: |
|
|
| ``` |
| <ip> - - [<timestamp>] "<METHOD> <path> HTTP/1.1" <status> <bytes> "<referer>" "<user-agent>" <duration_ms> |
| ``` |
|
|
| Some lines are damaged. The user-agent field may contain escaped double quotes |
| (`\"`), so the line cannot be parsed by splitting on `"` -- quoted fields have to |
| be scanned properly. `bytes` is `-` when the server did not record a size. |
|
|
| Write **`tools/report.sh`** in the workspace root. Running |
|
|
| ``` |
| bash tools/report.sh |
| ``` |
|
|
| from the workspace root must read `logs/access.log` and (re)generate the |
| following under `out/`, exit 0, and print nothing that matters. It must be |
| idempotent: deleting `out/` and running it again must produce byte-identical |
| files. |
|
|
| ## `out/report.json` |
|
|
| A JSON object with exactly these keys: |
|
|
| | key | type | meaning | |
| | --- | --- | --- | |
| | `total_requests` | int | number of **valid** lines | |
| | `unique_paths` | int | number of distinct normalised paths | |
| | `status_counts` | object | `{"<status>": <count>}`, keys are strings; only statuses that occur | |
| | `top_paths` | array | up to 3 objects `{"path": str, "count": int}`, highest count first, ties broken by path ascending | |
| | `bytes_total` | int | sum of `bytes` over valid lines, `-` counts as 0 | |
| | `p95_ms` | int | 95th percentile of `duration_ms`, nearest-rank method | |
|
|
| `p95_ms` is the nearest-rank percentile: sort the durations ascending, take |
| element number `ceil(0.95 * n)` counting from 1. With `n = 36` that is the 35th |
| smallest duration. If there are no valid lines, `p95_ms` is `0`. |
|
|
| Paths are normalised by dropping everything from the first `?` onwards, so |
| `/api/users?id=42` counts as `/api/users`. |
|
|
| ## `out/malformed.txt` |
|
|
| The 1-based line numbers of the lines that do not match the grammar above, one |
| per line, ascending. A line is malformed if any of these hold: it is not the |
| nine-part shape above, `status` is not exactly three digits, `bytes` is neither |
| `-` nor digits, or the trailing `duration_ms` is missing or not digits. |
| Malformed lines are excluded from every aggregate. |
|
|
| ## `out/access.log.gz` |
|
|
| A gzip stream whose decompressed content is byte-for-byte identical to |
| `logs/access.log`. |
|
|
| ## Notes |
|
|
| - Only `logs/access.log` is input; do not edit it. |
| - `python` is on `PATH` (`python3` is also available). Standard library only -- |
| there is no network access. |
|
|
