f96a998 · nix-container

git.iko.soy/nix-container

Use container start -ai: zellij as cmd, TERM via create env

commitf96a9981352af54af1e18e440b24f839202928d2 authoriko <mail@iko.soy> dateSun 28 Jun 2026, 09:39 (3 months ago) parent590e716

3 files changed+36−41

compare with master

unifiedsplit

README.md+6−5 c+9−17 flake.nix+21−19

README.md+6−5

@@ -90,18 +90,19 @@ nix run github:ilyakooo0/nix-container -- init

9090## Customize further

9191

9292Fork or clone to change what isn't per-project — `config.cmd`/`env` or the image

93−name — in [`flake.nix`](./flake.nix). The flake also exposes build helpers, both

94−taking a `{ pkgs, nur }: [ ... ]` function:

93+name — in [`flake.nix`](./flake.nix). The flake also exposes build helpers:

9594

96−- `lib.<system>.mkImage` → an OCI image.

97−- `lib.<system>.copyWith` → a skopeo copy app, for building/pushing the image

98− anywhere skopeo can write (e.g. a registry):

95+- `lib.<system>.copyWith` → a skopeo copy app for a `{ pkgs, nur }: [ ... ]`

96+ function, for building/pushing the image anywhere skopeo can write (e.g. a

97+ registry):

9998

10099 ```sh

101100 drv=$(nix build --no-link --print-out-paths --impure --expr \

102101 '(builtins.getFlake "github:ilyakooo0/nix-container").lib.${builtins.currentSystem}.copyWith (import ./container.nix)')

103102 $drv/bin/copy-to docker://ghcr.io/me/img:latest

104103 ```

104+- `lib.<system>.mkImage <name> <shell>` → the underlying OCI image (`copyWith`

105+ defaults these to `nix-container` / `bash`).

105106

106107The flake uses `flake-utils` over `{aarch64,x86_64}-{darwin,linux}`; the host

107108system maps to the matching Linux target automatically (an Intel Mac builds an

c+9−17

@@ -50,7 +50,7 @@ switch $argv[1]

5050 set -l tmp (mktemp -d)

5151 set -l archive $tmp/image.tar.gz

5252 set -lx NIX_CONTAINER_PKGS (path resolve $config)

53− set -l expr "(builtins.getFlake \"$flake\").lib.\${builtins.currentSystem}.copyWithShell \"$shell\" (import (/. + builtins.getEnv \"NIX_CONTAINER_PKGS\"))"

53+ set -l expr "(builtins.getFlake \"$flake\").lib.\${builtins.currentSystem}.copyWithShell \"nix-container-$name\" \"$shell\" (import (/. + builtins.getEnv \"NIX_CONTAINER_PKGS\"))"

5454 set -l copyer (nix build --impure --no-link --print-out-paths --expr "$expr")

5555 set -l rc $status

5656 if test $rc -eq 0

@@ -68,10 +68,11 @@ switch $argv[1]

6868 # Mount the project at /workspace (the default cwd).

6969 set -l mounts -v "$PWD:/workspace"

7070

71− # Replace any existing container of the same name. The image's cmd is the

72− # detected shell (holds the container open), so no command is passed.

71+ # Replace any existing container of the same name. The image's cmd is

72+ # zellij (`c start` attaches to it), so no command is passed here.

7373 container rm --force $name 2>/dev/null

74− # -e TERM: the runtime would otherwise force a bare "xterm" (see above).

74+ # -e TERM: baked into the container env so `container start -ai` gets it

75+ # (the runtime would otherwise force a bare "xterm").

7576 #

7677 # The image only lays down /bin and /etc, so /tmp and /run don't exist;

7778 # without them anything that writes temp files (zellij, build tools, …)

@@ -79,19 +80,10 @@ switch $argv[1]

7980 container create --name $name --ssh -it -e "TERM=$term" \

8081 --tmpfs /tmp --tmpfs /run --memory 8g --cwd /workspace $mounts $argv $image

8182 case start

82− # Boot the container detached (its PID1 shell keeps it alive), then attach

83− # the session with `exec -it`. `container start -ai` has no `-t` flag, so

84− # it never hands the guest a properly sized TTY: the real window size

85− # isn't delivered via the TIOCGWINSZ ioctl, so ioctl-based TUIs

86− # (crossterm/ncurses — helix, zellij, btop…) see 0×0 and render garbled,

87− # misaligned output. `exec -it` opens a real, correctly sized TTY, and

88− # `-e TERM` gives it the right terminal type.

89− #

90− # When the session exits, stop the container so it doesn't linger (the

91− # PID1 shell would otherwise keep it running); `c start` boots it again.

92− container start $name >/dev/null 2>&1; or exit 1

93− container exec -it -e "TERM=$term" --cwd /workspace $name zellij

94− container stop $name >/dev/null 2>&1

83+ # Start the container and attach to its cmd (zellij). TERM was baked into

84+ # the container env at create time (`-e TERM`), which survives this path.

85+ # Exiting zellij (PID1) stops the container; `c start` boots it again.

86+ container start -ai $name

9587 case '*'

9688 echo "usage: c init [-c FILE] [create args] | start" >&2

9789 exit 1

flake.nix+21−19

@@ -72,21 +72,22 @@

7272 # Host package set, for the wrapper app below.

7373 pkgsHost = nixpkgs.legacyPackages.${system};

7474

75− # Name/tag baked into the image's OCI config.

75+ # Default image name (for `copyWith`); `c init` passes a per-directory

76+ # name (`nix-container-<dir>`) to `copyWithShell` instead.

7677 imageName = "nix-container";

7778 imageTag = "latest";

7879

79− # Build the OCI image from a `{ pkgs, nur }: [ ... ]` package function,

80− # for the named shell. The shell is the image's `cmd` (a PID1 that just

81− # holds the container open — `c start` execs the real session into it)

82− # and the default `$SHELL`; it's added automatically, so `container.nix`

80+ # Build the OCI image (named `name`) from a `{ pkgs, nur }: [ ... ]`

81+ # package function, for the named shell. The image's `cmd` is zellij

82+ # (the session `c start` attaches to); the shell is the default `$SHELL`

83+ # (what zellij panes spawn) and is added automatically, so `container.nix`

8384 # lists only your extras. Nix (+ CA certs) and the ncurses terminfo

8485 # database are always shipped too. Nothing here is fish-specific: the

85− # TERM fixup now happens host-side in `c` (passed via `-e TERM`).

86+ # TERM fixup happens host-side in `c` (passed via `-e TERM` at create).

8687 mkImage =

87− shell: packages:

88+ name: shell: packages:

8889 n2c.buildImage {

89− name = imageName;

90+ inherit name;

9091 tag = imageTag;

9192 inherit arch;

9293

@@ -132,10 +133,10 @@

132133

133134 config = {

134135 # `cmd` (not `entrypoint`): the default command, *replaced* by any

135− # command passed to `container run/create`. It's the detected

136− # shell — as PID1 it just holds the container open; `c start`

137− # execs the real interactive session (zellij) into it.

138− cmd = [ "/bin/${shell}" ];

136+ # command passed to `container run/create`. It's zellij — the

137+ # session `c start` attaches to via `container start -ai`; exiting

138+ # it (PID1) stops the container.

139+ cmd = [ "/bin/zellij" ];

139140 env = [

140141 "PATH=/bin"

141142 "HOME=/root"

@@ -182,13 +183,14 @@

182183 lib = {

183184 inherit mkImage;

184185 # Build the image's `copyTo` script (a skopeo-copy wrapper) from a

185− # `{ pkgs, nur }: [ ... ]` function. Defaults the shell (cmd + $SHELL)

186− # to bash; use `copyWithShell` to pick another.

187− copyWith = packages: (mkImage "bash" packages).copyTo;

188− # Like `copyWith`, but for the named shell — `c init` passes the host

189− # login shell, which is added to the image and used as cmd + $SHELL

190− # without being listed in `container.nix`.

191− copyWithShell = shell: packages: (mkImage shell packages).copyTo;

186+ # `{ pkgs, nur }: [ ... ]` function, named `imageName`. Defaults the

187+ # shell (cmd + $SHELL) to bash; use `copyWithShell` to pick another.

188+ copyWith = packages: (mkImage imageName "bash" packages).copyTo;

189+ # Like `copyWith`, but for the given image `name` and shell — `c init`

190+ # passes `nix-container-<dir>` and the host login shell, which is added

191+ # to the image and used as cmd + $SHELL without being listed in

192+ # `container.nix`.

193+ copyWithShell = name: shell: packages: (mkImage name shell packages).copyTo;

192194 };

193195 }

194196 );