2b8c3ae6ee
ssh in and draw on a live, shared doodle wall -- everyone connected sees everyone else's edits in real time. Same wish+bubbletea security model as delve-term (no shell, no exec, structurally can't reach a real shell on the host), extended with the one thing delve-term didn't need: multiple sessions sharing live state. wish's bm.Middleware helper hides the *tea.Program it creates, so this builds the program directly instead, keeping a registry (game.Canvas) that broadcasts a redraw signal to every other connected session the instant one of them paints. Banner generated via `figlet -f slant SCRAWL` rather than hand-drawn -- slant felt right for a doodle/scribble tool. Two real bugs caught by actually running this with real SSH sessions, not just unit-testing the game logic in isolation: 1. Program.Send() blocks until that program's Run() event loop is actively reading from it. Broadcasting synchronously from inside Join()/Paint() (including a session broadcasting to its own, not-yet-running program on join) deadlocked every session before it ever reached Run() -- the very first connection just hung with nothing rendered. Fixed by sending asynchronously (go p.Send(...)) everywhere the canvas notifies sessions of a change. 2. Subtler: lipgloss's default package-level styles detect color support from the *server process's* os.Stdout, not any given session's actual terminal -- and a server's stdout is typically redirected (a log file, systemd journal), so every connected session silently lost all color/background styling at once, server-wide. Manifested as painting a cell your own cursor already sat on being invisible (the cursor glyph before/after looked identical, so bubbletea's diffing renderer correctly sent zero bytes for a change that produced no visual diff) -- confirmed via server-side debug logging that painting itself worked correctly every time, isolating the bug to rendering, then confirmed via a Go test that forcing a real color profile was the difference between 0 and 1327 runes of diff between two frames that should look different. Fixed with a lipgloss.Renderer created per-session, bound to that session's actual output, forced to TrueColor; cursors now highlight whatever's already painted at that cell (background tint) rather than replacing the character, so a session's own paint is never masked by its own cursor marker sitting on top of it. Verified end-to-end with two real, simultaneous SSH sessions (scripted via pexpect): peer count syncs correctly, and one session's paint genuinely arrives at the other via the live broadcast -- not just unit-tested in isolation. Also verified the actual Docker image builds and serves correctly over real SSH. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
16 lines
450 B
Docker
16 lines
450 B
Docker
FROM golang:1.24-alpine AS build
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WORKDIR /app
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COPY go.mod go.sum ./
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RUN go mod download
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COPY . .
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RUN CGO_ENABLED=0 go build -o /scrawl .
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FROM alpine:3.20
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RUN apk add --no-cache ca-certificates
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COPY --from=build /scrawl /usr/local/bin/scrawl
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# Host key persists in a volume — see docker-compose.yml — so it doesn't
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# regenerate (and change the server's fingerprint) on every redeploy.
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ENV HOST_KEY_PATH=/data/host_key
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EXPOSE 23235
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CMD ["scrawl"]
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