Docker CLI output parser

About this tool

Docker already has --format '{{json .}}', but that only helps when you can rerun the command. This parser is for the other common case: a pasted terminal transcript, a CI log, a ticket comment, or a saved docker ps / docker images / docker stats --no-stream table that needs to become structured data.

The tool uses Docker's header line as a fixed-width ruler. That matters because many Docker columns contain spaces in both the header and the value: CONTAINER ID, IMAGE ID, MEM USAGE / LIMIT, NET I/O, BLOCK I/O, COMMAND, CREATED, STATUS, and PORTS. A plain whitespace split mangles those rows; this parser keeps each cell in the column Docker printed.

With typed parsing enabled, the JSON output goes beyond raw strings:

• percentages such as CPU % and MEM % become numbers;
• PIDS becomes an integer;
• NAMES and PORTS become arrays;
• sizes gain byte counts;
• MEM USAGE / LIMIT, NET I/O, and BLOCK I/O split into separate usage/limit/input/output fields;
• Docker's -- placeholders become null.

Output can be JSON, CSV, TSV, Markdown, or an aligned text table. Choose snake_case keys for scripts, Docker-style keys for comparison with --format, or the original printed headers for spreadsheets.

Worked example

Input from docker ps:

CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS                    NAMES
9f21a1b2c3d4   nginx:1.25     "/docker-entrypoint.…"   3 minutes ago   Up 3 minutes   0.0.0.0:8080->80/tcp     web
0011deadbeef   postgres:16    "docker-entrypoint.s…"   2 hours ago     Up 2 hours                              db

JSON output starts like:

[
  {
    "container_id": "9f21a1b2c3d4",
    "image": "nginx:1.25",
    "command": "/docker-entrypoint.…",
    "created": "3 minutes ago",
    "status": "Up 3 minutes",
    "ports": ["0.0.0.0:8080->80/tcp"],
    "names": ["web"]
  }
]

Switch to CSV when you are pasting into a spreadsheet, Markdown for an incident report, or a plain table when you only want selected columns aligned for a chat reply.

Limits and edge cases

• The input must include a header row. Without it, there is no reliable way to know where columns begin or what schema the output should use.
• Docker version and flags change headers. Unknown columns are preserved and normalized; derived typed fields are added only for known Docker shapes.
• strict mode is useful for CI logs: it fails on a header/kind mismatch or a row that looks truncated. Leave it off for messy ticket snippets.
• Fixed-width parsing follows the header spans Docker printed. If a terminal wrapped a long row onto multiple lines, unwrap it before parsing.
• This does not connect to Docker, inspect containers, or read a Docker socket. It only parses pasted text locally in your browser.

FAQ