@@ -72,71 +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− # Fish prompt config. Installed at /etc/fish/prompt.fish and loaded via
80− # `fish --no-config --init-command` (see `cmd` below), NOT from
81− # $HOME/.config/fish — so the `~/.config` mount can't shadow it. Built
82− # on the host arch (just a text file), so no Linux builder is needed.
83− fishConfig = pkgsHost.writeText "prompt.fish" ''
84− # No welcome banner.
85− set -g fish_greeting
86−
87− # Pick a TERM whose terminfo entry actually exists in the bundled
88− # database, so TUIs render with the right capabilities (otherwise
89− # they glitch on redraw). The container runtime strips the host TERM
90− # down to a bare "xterm"; `c` forwards the real value as HOST_TERM.
91− # Ghostty reports "xterm-ghostty", but ncurses ships that entry under
92− # the name "ghostty", so map it. Prefer HOST_TERM over the runtime's
93− # bare "xterm" placeholder, falling back to xterm-256color.
94− for term_candidate in $HOST_TERM $TERM xterm-256color
95− test "$term_candidate" = xterm; and continue
96− set -l entry $term_candidate
97− test "$entry" = xterm-ghostty; and set entry ghostty
98− if infocmp $entry >/dev/null 2>&1
99− set -gx TERM $entry
100− break
101− end
102− end
103− set -q COLORTERM; or set -gx COLORTERM truecolor
104−
105− # Define the prompt as a function so fish renders it before every
106− # command; at top level it would run once at startup and be ignored.
107− function fish_prompt
108− set -l nix_shell_info
109− if set -q IN_NIX_SHELL; or set -q IN_NIX_RUN
110− set nix_shell_info ' ❄️'
111− end
112−
113− set -l cwd (prompt_pwd)
114−
115− set -l bookmark_info
116− if jj root 2>/dev/null >/dev/null
117− set -l jj_bookmark (jj log -r 'heads(::@ & bookmarks())' -T 'local_bookmarks ++ "\n"' --no-graph 2>/dev/null | tail -1)
118− if test -n "$jj_bookmark"
119− set bookmark_info ' ' (set_color brmagenta) $jj_bookmark (set_color normal)
120− end
121− end
122−
123− echo -n -s (set_color $fish_color_cwd) $cwd (set_color normal) $bookmark_info ' 🏗️' $nix_shell_info '> '
124− end
125− '';
126−
127− # Lay the prompt out at the path the cmd sources.
128− fishRoot = pkgsHost.runCommand "fish-prompt" { } ''
129− mkdir -p "$out/etc/fish"
130− cp ${fishConfig} "$out/etc/fish/prompt.fish"
131− '';
132−
133− # Build the OCI image from a `{ pkgs, nur }: [ ... ]` package function.
134− # The image always runs /bin/fish; fish, its prompt config, and Nix are
135− # bundled automatically, so `container.nix` lists only your extras.
80+ # Build the OCI image (named `name`) from a `{ pkgs, nur }: [ ... ]`
81+ # package function, for the named shell. The image's `cmd` is herdr
82+ # (the session `c start` attaches to); the shell is the default `$SHELL`
83+ # (what herdr panes spawn) and is added automatically, so `container.nix`
84+ # lists only your extras. Nix (+ CA certs) and the ncurses terminfo
85+ # database are always shipped too. Nothing here is fish-specific: the
86+ # TERM fixup happens host-side in `c` (passed via `-e TERM` at create).
13687 mkImage =
137− packages:
88+ name: shell: packages:
13889 n2c.buildImage {
139− name = imageName;
90+ inherit name;
14091 tag = imageTag;
14192 inherit arch;
14293
@@ -144,10 +95,6 @@
14495 # buildEnv only *symlinks* paths (never runs them), so build it on
14596 # the host arch — the tree is arch-neutral and links the
14697 # (substituted) Linux store paths, sparing the Linux builder.
147− #
148− # Always shipped: fish (the cmd) + its prompt, and Nix (+ CA certs)
149− # so every container can use Nix; `initializeNixDatabase` registers
150− # the baked store.
15198 copyToRoot = pkgsHost.buildEnv {
15299 name = "root";
153100 paths =
@@ -155,24 +102,27 @@
155102 pkgs = pkgsLinux;
156103 nur = nurPkgs;
157104 }
105+ # The shell (cmd + $SHELL), when it exists in nixpkgs.
106+ ++ pkgsLinux.lib.optional (pkgsLinux ? ${shell}) pkgsLinux.${shell}
158107 ++ [
159− pkgsLinux.fish
160− fishRoot
161108 pkgsLinux.nix
162109 pkgsLinux.cacert
110+ # Basic userland (ls, cat, cp, sleep, …) so the container is
111+ # usable out of the box and tools that shell out don't fail.
112+ pkgsLinux.coreutils-full
163113 # Networking glue glibc needs: /etc/nsswitch.conf (+passwd,
164114 # group) so DNS/host lookups resolve, and /etc/protocols,
165115 # /etc/services. Without these, hostname resolution fails.
166116 pkgsLinux.fakeNss
167117 pkgsLinux.iana-etc
168− # Terminfo tools (infocmp/tput/clear/reset). The terminfo DB
169− # itself already ships via fish's ncurses dependency; this
170− # puts the lookup tools on PATH so the prompt init can pick a
171− # TERM entry that exists, and TUIs get correct capabilities.
118+ # The terminfo database (+ tput/clear/reset) so TUIs find the
119+ # entry for whatever TERM `c` passes in and render correctly.
172120 pkgsLinux.ncurses
121+ # The session `c start` always launches.
122+ pkgsLinux.herdr
173123 ];
174124 # Link all of /etc so the above files (nsswitch.conf, protocols,
175− # services, passwd, group, ssl certs, fish prompt) are present.
125+ # services, passwd, group, ssl certs) are present.
176126 pathsToLink = [
177127 "/bin"
178128 "/etc"
@@ -183,26 +133,20 @@
183133
184134 config = {
185135 # `cmd` (not `entrypoint`): the default command, *replaced* by any
186− # command passed to `container run/create`. `--no-config` skips
187− # $HOME/.config/fish (so a mounted ~/.config can't override the
188− # prompt); `--init-command` loads the bundled prompt instead.
189− cmd = [
190− "/bin/fish"
191− "--no-config"
192− "--init-command"
193− "source /etc/fish/prompt.fish"
194− ];
136+ # command passed to `container run/create`. Plain herdr here;
137+ # `c init` overrides it with `herdr session attach <dir>-container` so
138+ # the session is named per project. `c start` attaches via
139+ # `container start -ai`; exiting herdr (PID1) stops the container.
140+ cmd = [ "/bin/herdr" ];
195141 env = [
196142 "PATH=/bin"
197143 "HOME=/root"
198− # Default shell for tools that spawn one (zellij panes, etc.);
199− # without it they fall back to /bin/sh.
200− "SHELL=/bin/fish"
144+ # Default shell for tools that spawn one (herdr panes, etc.).
145+ "SHELL=/bin/${shell}"
201146 # Marker so shells/scripts can detect they're in here.
202147 "NIX_CONTAINER=1"
203− # Advertise truecolor so `container exec` sessions (which don't
204− # source the fish init) still get 24-bit color. TERM is fixed up
205− # in the fish prompt init, since the runtime overrides it here.
148+ # Advertise truecolor for 24-bit-aware tools; `c` passes the
149+ # resolved TERM via -e (the runtime would otherwise force xterm).
206150 "COLORTERM=truecolor"
207151 # A UTF-8 locale so tools handle multibyte/wide characters
208152 # correctly. glibc ships C.UTF-8 built in, so this needs no
@@ -220,7 +164,7 @@
220164
221165 # `nix run . -- init|start` runs the bundled `c` manager script. Its
222166 # `init` builds the image from the project's `container.nix` (via
223− # `lib.copyWith`); the script finds the flake from its own (store)
167+ # `lib.copyWithShell`); the script finds the flake from its own (store)
224168 # location, so this works from a checkout or straight from
225169 # `nix run github:…/nix-container`.
226170 cApp = pkgsHost.writeShellScriptBin "c" ''
@@ -233,24 +177,22 @@
233177 default = flake-utils.lib.mkApp { drv = cApp; };
234178 };
235179
236− # Build helpers. `c init` uses `copyWith` to honour a per-project
237− # `container.nix`:
180+ # Build helpers take a `{ pkgs, nur }: [ ... ]` packages function (the
181+ # `packages` attr of a project's `container.nix`). `c init` uses
182+ # `copyWithShell` (host shell baked in); `copyWith` is the generic form:
238183 # (builtins.getFlake "github:…/nix-container")
239− # .lib.<system>.copyWith (import ./container.nix)
184+ # .lib.<system>.copyWith (import ./container.nix).packages
240185 lib = {
241186 inherit mkImage;
242− # skopeo copy app (`skopeo copy nix:<image> "$@"`) for an image built
243− # from a `{ pkgs, nur }: [ ... ]` function.
244− copyWith = packages: (mkImage packages).copyTo;
245− # Like `copyWith`, but also adds the named shell package (when it
246− # exists in nixpkgs) so `c init` can make the host shell available
247− # without it being listed in `container.nix`.
248− copyWithShell =
249− shell: packages:
250− (mkImage (
251− { pkgs, nur }:
252− packages { inherit pkgs nur; } ++ pkgs.lib.optional (pkgs ? ${shell}) pkgs.${shell}
253− )).copyTo;
187+ # Build the image's `copyTo` script (a skopeo-copy wrapper) from a
188+ # `{ pkgs, nur }: [ ... ]` function, named `imageName`. Defaults the
189+ # shell (cmd + $SHELL) to bash; use `copyWithShell` to pick another.
190+ copyWith = packages: (mkImage imageName "bash" packages).copyTo;
191+ # Like `copyWith`, but for the given image `name` and shell — `c init`
192+ # passes `nix-container-<dir>` and the host login shell, which is added
193+ # to the image and used as cmd + $SHELL without being listed in
194+ # `container.nix`.
195+ copyWithShell = name: shell: packages: (mkImage name shell packages).copyTo;
254196 };
255197 }
256198 );