chartjs2img-install

name	chartjs2img-install
description	Install or update the chartjs2img CLI from the latest GitHub release. Use when the user asks to install chartjs2img, set up the binary, update / upgrade to the newest version, or when another chartjs2img skill reports that the `chartjs2img` command is missing from PATH. Detects OS + arch, picks the right release archive, tries a writable directory on PATH (~/.local/bin, /usr/local/bin, etc.), and falls back to dropping the binary in /tmp with a sudo hint if nothing is writable.
license	MIT
compatibility	Requires curl (or wget), tar (linux/macos) or unzip (windows), and network access to github.com / api.github.com. Standalone — does NOT need `chartjs2img` to already be installed. The default `skia` engine needs no browser; only the optional `browser` engine auto-downloads Chromium on first use (except on linux-arm64; see notes).
allowed-tools	Bash(curl:*) Bash(wget:*) Bash(tar:*) Bash(unzip:*) Bash(which:*) Bash(command:*) Bash(uname:*) Bash(mkdir:*) Bash(mv:*) Bash(cp:*) Bash(rm:*) Bash(chmod:*) Bash(ls:*) Bash(echo:*) Bash(test:*) Bash(sh:*) Bash(bash:*) Read Write

chartjs2img-install

Install or update the chartjs2img CLI from the GitHub Releases of ideamans/chartjs2img, cross-platform.

This skill is one of several ways to install chartjs2img. If the user already prefers their own install method (Homebrew, a system package manager, bun install -g chartjs2img once published, or building from source via bun run build), confirm they want to use this skill before proceeding. Any install that puts chartjs2img on $PATH works equally well; the other chartjs2img skills don't care how the binary got there.

Workflow

1. Detect platform

uname -s       # Linux / Darwin / MINGW* / MSYS* → windows
uname -m       # x86_64 / arm64 / aarch64

Normalize to the release-asset naming (note: release uses underscore form linux_amd64, not linux-amd64):

uname -s	os
Linux	linux
Darwin	darwin
MINGW* / MSYS* / CYGWIN*	windows

uname -m	arch
x86_64 / amd64	amd64
aarch64 / arm64	arm64

Release assets follow chartjs2img_<version>_<os>_<arch>.<ext> where <ext> is zip for windows and tar.gz for everything else.

Supported combinations: linux_amd64, linux_arm64, darwin_arm64, windows_amd64. Two targets are NOT built — if the user is on one, tell them and stop:

• Intel Mac (darwin_amd64) — Mac binaries are Apple Silicon only. Intel users can run via bun / Docker / npm, or build from source.
• Windows ARM64 — they can build from source with bun run build on a native Windows ARM64 machine if they need it.

2. Look up the latest release

Use the GitHub API; no auth needed for public repos:

curl -fsSL https://api.github.com/repos/ideamans/chartjs2img/releases/latest \
  | grep -o '"tag_name": *"[^"]*"' | head -1 | sed 's/.*"\(v[0-9.]*\)"/\1/'

Call the result TAG (e.g. v0.2.2). Version without the v is VER.

Asset URL:

https://github.com/ideamans/chartjs2img/releases/download/<TAG>/chartjs2img_<VER>_<os>_<arch>.<ext>

3. Check if chartjs2img is already installed

if command -v chartjs2img >/dev/null 2>&1; then
  INSTALLED_PATH="$(command -v chartjs2img)"
  INSTALLED_VERSION="$(chartjs2img --version 2>&1 | grep -oE 'v[0-9.]+' || echo 'unknown')"
else
  INSTALLED_PATH=""
fi

• If INSTALLED_PATH is non-empty: this is an update. Target directory is the parent of INSTALLED_PATH.
• Already at the latest version: tell the user and stop.

4. Pick a writable install directory (fresh install only)

Candidate list in order of preference:

Path	Rationale
$HOME/.local/bin	User-local, no sudo. XDG base dir default.
$HOME/bin	Older convention, still common.
/usr/local/bin	Classic system-wide. Writable on most macOS + Homebrew setups.
/opt/homebrew/bin	Apple Silicon Homebrew.

For each candidate, verify it's on $PATH and writable:

for d in "$HOME/.local/bin" "$HOME/bin" "/usr/local/bin" "/opt/homebrew/bin"; do
  case ":$PATH:" in *":$d:"*) :;; *) continue;; esac
  if [ -d "$d" ] && [ -w "$d" ]; then
    echo "ok: $d"
  elif [ ! -d "$d" ] && mkdir -p "$d" 2>/dev/null; then
    echo "ok: $d (created)"
  fi
done

• Match found → ask the user which to install into (default ~/.local/bin).
• No match → sudo fallback (step 6).

5. Download and install

ASSET="chartjs2img_${VER}_${OS}_${ARCH}.${EXT}"
URL="https://github.com/ideamans/chartjs2img/releases/download/${TAG}/${ASSET}"
TMP=$(mktemp -d)
curl -fsSL -o "$TMP/$ASSET" "$URL"

# Also fetch + verify the checksum
curl -fsSL -o "$TMP/$ASSET.sha256" "$URL.sha256"
( cd "$TMP" && sha256sum -c "$ASSET.sha256" )

if [ "$EXT" = "zip" ]; then
  unzip -q "$TMP/$ASSET" -d "$TMP"
  BIN="$TMP/chartjs2img.exe"
else
  tar -xzf "$TMP/$ASSET" -C "$TMP"
  BIN="$TMP/chartjs2img"
fi

chmod +x "$BIN"
mv "$BIN" "$TARGET_DIR/"
rm -rf 

Verify:

"$TARGET_DIR/chartjs2img" --version

Should print chartjs2img v<VER>. If it fails, fall back to step 6.

6. Sudo fallback

When no writable PATH directory exists (or step 5's move returned EACCES):

FALLBACK="/tmp/chartjs2img"
cp "$BIN" "$FALLBACK"
chmod +x "$FALLBACK"
echo "chartjs2img is ready at $FALLBACK."
echo "Install it system-wide with:"
echo "  sudo mv $FALLBACK /usr/local/bin/chartjs2img"

Do not run sudo from the skill — that needs a terminal.

Chromium note (browser engine only)

The default skia engine renders with no browser, so most users never need Chromium. It is only required for the optional --engine browser path. When that engine is used, chartjs2img auto-downloads Chrome for Testing on first use for macOS/Windows/Linux-x64 (~250 MB into the user cache). linux-arm64 is not covered by Chrome for Testing — on that platform, if the user wants the browser engine, tell them to apt install chromium-browser (or equivalent) and set CHROMIUM_PATH:

export CHROMIUM_PATH=/usr/bin/chromium-browser

The install skill itself doesn't fetch Chromium. chartjs2img handles that on its own the first time a render is requested; the install skill just warns the linux-arm64 user upfront.

Reporting back to the user

Always finish with a summary line:

• chartjs2img installed at ~/.local/bin/chartjs2img (v0.2.2 → new)
• chartjs2img updated at /usr/local/bin/chartjs2img (v0.2.0 → v0.2.2)
• chartjs2img already at the latest version (v0.2.2) at …
• chartjs2img staged at /tmp/chartjs2img — run 'sudo mv /tmp/chartjs2img /usr/local/bin/' to finish

Edge cases

• No curl: try wget next. Neither available → stop and report clearly.
• Network / rate limit: propagate the HTTP status. For GitHub API rate limits, suggest retrying or setting GITHUB_TOKEN.
• Arch mismatch (x86_64 userland under Rosetta on Apple Silicon): trust uname -m; if the resulting binary fails --version with "cannot execute binary file", retry with the other arch.
• Existing chartjs2img installed by npm global / bun link: still update in place at command -v chartjs2img. Don't try to uninstall the previous method.
• Behind a corporate proxy: the user will need to set HTTPS_PROXY / HTTP_PROXY before curl. Flag this if the initial download fails with a connection error.

After a successful install

• If ~/.local/bin was just created, suggest exec $SHELL or a new terminal so PATH picks it up.
• Suggest smoke tests:

  chartjs2img --version
  chartjs2img llm | head -10
  echo '{"type":"bar","data":{"labels":["A"],"datasets":[{"data":[1]}]}}' \
    | chartjs2img render -o /tmp/smoke.png
  

  The render step also triggers Chromium auto-download on first run.