4 This is a wrapper tool for cargo, the Rust build tool and package
7 * Conveniently use local crates, including completely
9 * Perform out-of-tree builds, including in an account with
10 no write access to the source tree.
11 * Provide convenience aliases for target architecture names.
12 * Make the default be offline (ie, not to access the internet).
14 These functions are of course configurable.
16 The primary source of information for nailing-cargo is the file
17 `../Cargo.nail` (which is in TOML syntax). You put `Cargo.nail`
18 alongside the top-level git repositories you are working with, and
19 invoke nailing-cargo from the git directory containing the Rust
20 package you want to build.
25 nailing-cargo is designed to be run out of a git clone:
28 $ git clone https://salsa.debian.org/iwj/nailing-cargo.git
29 $ ln -s `pwd`/nailing-cargo/nailing-cargo ~/bin
32 It is self-contained, depending only on a reasonably functional Perl
35 Most basic example usage
36 ------------------------
45 $ nailing-cargo -u fetch
49 Documentation table of contents
50 -------------------------------
52 <!-- TOC autogenerated by ./markdown-toc-filter, do not edit -->
54 * [Introduction](#nailing-cargo)
55 * [Installing](#installing)
56 * [Most basic example usage](#most-basic-example-usage)
57 * [Documentation table of contents](#documentation-table-of-contents)
58 * [Using local crates, or locally modified crates](#using-local-crates-or-locally-modified-crates)
59 * [How nailing-cargo helps with using local crates](#how-nailing-cargo-helps-with-using-local-crates)
60 * [Telling nailing-cargo how to massage `Cargo.toml`](#telling-nailing-cargo-how-to-massage-cargo.toml)
61 * [Out-of-tree builds](#out-of-tree-builds)
62 * [How nailing-cargo helps with out-of-tree builds](#how-nailing-cargo-helps-with-out-of-tree-builds)
63 * [Configuring out-of-tree builds](#configuring-out-of-tree-builds)
64 * [Target architecture convenience aliases](#target-architecture-convenience-aliases)
65 * [Default change to offline mode](#default-change-to-offline-mode)
66 * [Invocation and command-line option reference](#invocation-and-command-line-option-reference)
69 * [Environment of the build command](#environment-of-the-build-command)
70 * [Configuration reference](#configuration-reference)
71 * [Source directories and packages (toplevel)](#source-directories-and-packages-toplevel)
72 * [`[alt_cargolock]`: Alternative `Cargo.lock` filename](#alt_cargolock-alternative-cargo.lock-filename)
73 * [`[oot]`: Out-of-tree build support](#oot-out-of-tree-build-support)
74 * [`[arch]`: Architecture convenience aliases](#arch-architecture-convenience-aliases)
75 * [`[misc]`: Miscellaneous individual nailing-cargo config](#misc-miscellaneous-individual-nailing-cargo-config)
76 * [Limitations and bugs](#limitations-and-bugs)
77 * [Contributing and legal](#contributing-and-legal)
80 Using local crates, or locally modified crates
81 ==============================================
83 cargo does not work well with local crates,
84 especially completely unpublished ones.
85 (See [issue#6713](https://github.com/rust-lang/cargo/issues/6713),
86 [stackoverflow](https://stackoverflow.com/questions/33025887/how-to-use-a-local-unpublished-crate),
87 [issue#1481](https://github.com/rust-lang/cargo/issues/1481),
88 [my blog](https://diziet.dreamwidth.org/1805.html).)
90 Using a local version of a crate should be possible without putting
91 paths into your `Cargo.toml` and without editing complex
94 How nailing-cargo helps with using local crates
95 -----------------------------------------------
97 nailing-cargo temporarily edits all the `Cargo.toml` files in all the
98 subdirectories you mention, to refer to each other; then it runs
99 cargo; and then it puts everything back.
101 Telling nailing-cargo how to massage `Cargo.toml`
102 -------------------------------------------------
104 To find the subdirectories, and the packages, nailing-cargo looks for
105 `subdirs` and `packages` in `Cargo.nail`.
107 For straightforward use, write `subdirs` as a multi-line string
108 containing a list of subdirectory names one per line. In each of
109 these directories `Cargo.toml` will be massaged, and the package there
110 will be used for other massaged `Cargo.toml`s.
112 See the [Configuration reference](#configuration-reference) for full details.
114 Scope of nailing-cargo's local crate functionality
115 --------------------------------------------------
117 nailing-cargo's `Cargo.toml` massaging will allow you to easily build
118 an interdepending set of local packages, possibly even including
119 private unpublished packages, and/or locally-modified versions of
120 published packages. These local packages can freely depend on
121 published packages (eg from `crates.io`) in the usual way.
123 Compared to the corresponding cargo feature, nailing-cargo's approach:
124 (i) works even for local crates that have not been published anywhere; and
125 (ii) is a lot simpler to configure.
127 But nailing-cargo's local crate support won't work if any non-local
128 crate needs to be rebuilt against a local crate (ie, a local version
129 of one of its dependencies). If that is your requirement, either make
130 local versions of the intermediate crates in the dependency graph, or
131 use the cargo override facility --- see [Overriding
132 Dependencies](https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html)
138 It is often desirable to run builds in a way that does not write to
139 the source tree. cargo's enthusiastic approach to the dependency
140 management task means that it is a good idea to try to insulate your
141 main working environment from the many things cargo has decided to
142 download and execute.
144 However, when you tell cargo to do an out of tree build (using
145 `--manifest-path`) it will insist on `Cargo.lock` being in the source
146 directory, and often will insist on writing to it.
148 How nailing-cargo helps with out-of-tree builds
149 -----------------------------------------------
151 nailing-cargo (configured appropriately) copies files back and forth
152 to between the source and build directories, and runs cargo as your
155 The `Cargo.lock` must still be saved in your source tree somewhere.
156 nailing-cargo arranges this for you. You can either put this file in
157 `.gitignore`; or commit it to git; or you can tell nailing-cargo to
158 save it as something like `Cargo.lock.example`.
160 Configuring out-of-tree builds
161 ------------------------------
163 To enable out-of-tree-builds, put an `[oot]` section in your
164 `Cargo.nail` or one of nailing-cargo's other config files.
165 In that section, specify at least `use`.
167 Also, specify `dir`, or create a symlink `Build` next to `Cargo.nail`,
168 pointing to to your build area.
176 will have nailing-cargo run `ssh rustcargo@localhost` to
179 Target architecture convenience aliases
180 =======================================
182 If you are cross-building you may need to tell cargo `--target=`.
183 The architecture names are quite long and inconvenient.
185 A simple shell alias would help a lot, except that cargo rejects
186 `--target=` when it thinks it's not needed.
188 In your nailing-cargo config, you can write something like
189 `arch.RPI='arm-unknown-linux-gnueabihf'`. Then `nailing-cargo -TRPI`
190 will DTRT. In fact, you do not even need to specify that particular
191 arch alias, since it is built-in to nailing-cargo.
193 Default change to offline mode
194 ==============================
196 It seems to me that build tools should be explicit about their use of
197 the network. So by default, nailing-cargo passes `--offline` to
200 If you disagree with my opinion, write `misc.online=true` in your
201 nailing-cargo configuration. `misc.online=false`, and command line
202 options, are also available, for overriding.
204 If you agree with me, you may wish to use `nailing-cargo
205 generate-lockfile`, which can update (even an existing) `Cargo.lock`
206 without going online, instead of `update`.
208 Invocation and command-line option reference
209 ============================================
215 1$ nailing-cargo <nailing-opts> <cargo-opts> [--] <subcmd>...
216 2$ nailing-cargo <nailing-opts> --- <cargo> <cargo-opts> [--] <subcmd>...
217 3$ nailing-cargo <nailing-opts> --- [--] <build-command>...
219 Ususally the `--` is not needed. (It should generally be passed by
220 programs which wrap nailing-cargo. See [Invocation argument disambiguation rules](#invocation-argument-disambiguation-rules), below.)
222 In usage 1, nailing-cargo runs `cargo` (from `PATH`). In the usage 2
223 nailing-cargo runs `<cargo>`. In both these cases it adds its own
224 options to control cargo's behaviour. In both of these cases
225 nailing-cargo looks at `<subcmd>` to determine the cargo subcommand
226 being run: this controls various defaults, to try to do the right
229 In the third syntax, nailing-cargo runs `<build-command>...` without
230 additional arguments and does not attempt to identify the cargo
231 subcommand(s) that it will run. Possibly it will be necessary to pass
232 `--online` or `--cargo-lock-update`, or even `--cargo-*arg*`
234 ### Invocation argument disambiguation rules ###
236 For authors of tools which call nailing-cargo (and pedants):
238 The usages overlap in syntax! nailing-cargo follows the following
239 rules when interpreting its command line:
241 * The first option not recognised as a nailing-cargo option is
242 treated as the start of the `<cargo-opts>`.
244 * `<cargo-opts>` are terminated by `--` (which is removed) or the
245 first argument which does not start with a `-`.
247 (It is not possible to get nailing-cargo to pass the value `--`
248 as a separate argument to a cargo global option, but cargo global
249 options can typically take the values cuddled with `=`, so doing
250 that is not necessary.)
252 * After `---`, nailing-cargo will search for a `--`, to the end of
253 the arguments if necessary. The position of the `--` determines
254 whether this is usage 2 or usage 3, and what `<subcmd>` is.
256 If the arguments after `nailing-cargo ... ---` might contain `--`
257 anywhere, an explicit `--` should be passed.
259 * If no `--` appears after `---`, the word after `---` is the
260 command to run; if its final pathname component contains the
261 string `cargo`, it is treated as `<cargo>` (implying usage 2 and
262 the search for `<subcmd>`). Otherwise it is treated as
263 `<build-command>` (usage 3).
268 * `-v`: Increase verbosity. Default is 1.
270 * `-q`: Set verbosity to 0.
272 * `-D`: Increase amount of debugging dump.
274 * `-n`: "No action": stop after writing `Cargo.toml.nailing~`
275 everywhere, and do not run any build command.
277 * `-T<arch>` | `--target=<arch>`
279 Specify target architecture.
281 This option translates to a `--target=<arch>` option to cargo
282 (when the subcommand accepts it).
284 If `<arch>` starts with a capital ascii letter, it is an alias
285 for some other arch: it is looked up in the configuration, and
286 then in the builtin arch alias list. The builtin list is
287 equivalent to: `[arch]` `RPI='arm-unknown-linux-gnueabihf'`.
289 * `-o` | `--online` | `-O` | `--offline`
291 Whether to allow cargo to make network access. nailing-cargo
292 always passes `--offline` to cargo, unless `--online` is in
293 force. The default value depends on the configuration and the
294 cargo subcommand - see [`[misc]` `online`](#misc_online),
297 * `-u` | `--cargo-lock-update` | `-U` | `--no-cargo-lock-update`
299 Allows (or disallows) cargo to update `Cargo.lock` in the source
300 directory. Without this enabled, nailing-cargo passes `--locked`
303 With this enabled, in an out-of-tree build the `Cargo.lock` and
304 `Cargo.toml` are copied to the build directory along with a
305 linkfarm, to fool cargo. After cargo has run, the resulting
306 `Cargo.lock` is copied back to the source tree.
308 Default is no update unless the whole point of the cargo
309 subcommand is to update `Cargo.lock`.
313 Controls the addition of cargo command line options; ie,
314 whether nailing-cargo should treat the build command as if it
316 With `-C`, nailing-cargo will not add additional options
317 to the build command. With `-c` it will pass those options
318 after the cargo subcommand (usages 1 and 2) or right
319 after the build command (usage 3).
321 The cargo options are in any case also passed in the
322 environment - see [Environment of the build command](#environment-of-the-build-command).
324 The default is to pass cargo options if the command line
325 parsing yielded a cargo command and options (usages 1 and 2),
326 rather than a non-cargo build command (usage 3). `-C` and `-c`
327 do not affect the parsing of nailing-cargo's command line.
329 * <a name="s_subcommand">`-s<subcommand>`</a>
331 Behave as if the build command were `cargo <subcommand>`.
332 This influences the logic which tries to determine which
333 options to pass to cargo, whether cargo needs to be online, and
334 whether cargo might want to update `Cargo.lock`.
336 nailing-cargo knows about `update`, `generate-lockfile` and
337 `fetch`; all other subcommands are (silently) treated the same way
338 as `build` (ie, no subcommand properties). See
339 `--subcommand-props` for more detail about how the
340 subcommand affects nailing-cargo's behaviour.
342 The default is to use the cargo subcommand found from parsing
343 nailing-cargo's command line. NB: `-s` does not affect
344 which build command (and which cargo subcommand) is actually run.
346 * <a name="subcommand_props">`--subcommand-props=<prop>,...`</a>
348 Specify the properties of the subcommand. This is an
349 alternative to `-s<subcmd>`. The usual properties are:
351 * `lock_update`: cargo will want to update `Cargo.lock`. (The `-u` and `-U` options override this.)
352 * `online`: this subcommand makes no sense to run offline. (The `-o` and `-O` options, and the configuration, can override this.)
353 * `!target`: cargo would reject `--target=<arch>`; in this case nailing-cargo's `-T` option is ineffective.
354 * `!target-dir`: cargo would reject `--target-dir`, so don't pass it. (Usually we pass `--target-dir=target` when we pass `--manifest-path`, since cargo's default is `target` in the same directory as `Cargo.toml`.)
357 There are also some properties which should not be needed, but are
358 provided for completeness. Do not use these to solve the problem
359 of nailing-cargo passing cargo options to a build command which is
360 not cargo - use `-C` for that. The properties whose use is discouraged:
362 * `!manifest-path`: cargo would reject `--manifest-path`, so don't pass it (and don't pass `--target-dir` either). Only makes any difference for out-of-tree builds. Things will probably go wrong unless the build command looks at `[NAILING]CARGO_MANIFEST_DIR`.
363 * `!locked`: cargo would reject `--locked`, so don't pass it. Hazardous.
364 * `!offline`: the build command would reject `--offline`, so never pass it. *Not* overridden by configuration or command line.
366 * `-h` | `--help`: Print usage summary.
368 Environment of the build command
369 --------------------------------
371 nailing-cargo passes these environment variables to the build command:
373 * `CARGO_MANIFEST_DIR`: invocation `.` (invocation directory)
374 * `NAILINGCARGO_MANIFEST_DIR`: same as `CARGO_MANIFEST_DIR`
375 * `NAILINGCARGO_WORKSPHERE`: invocation `..` (parent)
376 * `NAILINGCARGO_BUILD_DIR`: build directory (even if same as source)
377 * `NAILINGCARGO_BUILDSPHERE`: parent of build dir (only set if out-of-tree)
378 * `NAILINGCARGO_CARGO_OPTIONS`: additional options that nailing-cargo passed (or would pass) to cargo. Space-separated; does not include `--manifest-path`.
380 All of these are absolute paths.
382 ### Build commands which wrap cargo ###
384 If you specify a build command which eventually runs cargo, you may
385 wish to pass on to your cargo the options which nailing-cargo would
386 have passed. This will definitely be necessary if you are using nailing-cargo's out-of-tree facility.
388 In such a situation, do it like this:
390 cargo build --manifest-path="${CARGO_MANIFEST_DIR-.}"/Cargo.toml $NAILINGCARGO_CARGO_OPTIONS
393 If you need to run a cargo subcommand which doesn't understand some of
394 nailing-cargo's options, currently, you must strip them out of
395 `NAILINGCARGO_CARGO_OPTIONS` yourself - or pass some `-s` or
396 `--subcmd-props` option to nailing-cargo (but that is a layering
397 violation and may not work if one build command runs various different
400 Configuration reference
401 =======================
403 nailing-cargo reads these configuration files:
405 /etc/nailing-cargo/cfg.toml
406 ~/.nailing-cargo.toml
407 ./.nailing-cargo.toml
408 ../Nailing-Cargo.toml
411 Settings in later-mentioned files override ones in earlier-mentioned
414 Source directories and packages (toplevel)
415 ------------------------------------------
417 Note that unlike everything else, these keys (`packages` and
418 `subdirs`) are read only from `Cargo.nail` (see "Limitations and
421 These keys specify a combination of (i) a mapping from package name to
422 source subdirectory (ii) a set of subdirectories whose `Cargo.toml`
425 * `packages`: a map keyed by package name, giving the subdirectory
428 This causes each mentioned subdirectory's `Cargo.toml` to be
429 massaged, and records that subdirectory as the source for that
430 package. (nailing-cargo will check that subdirectory actually
431 contains the indicated package.)
433 Each value can be just the subdirectory name (eg `[packages]`
434 `mylibrary='mylibrary-test'`) or itself a map with the key `subdir`
435 (eg `[packages.mylibrary]` `subdir='mylibrary-test'`).
437 * `subdirs`: a list of subdirectory names to process.
439 Each subdirectory's `Cargo.toml` will be massaged. Also, the
440 subdirectory will be examined to see what package it contains; it
441 will then be used as the source for that package, unless that
442 package appears in an entry in `packages`, or an earlier entry in
445 This can be a list of strings (eg `subdirs =
446 ['myproject','mylibrary']`). Or it can be single multi-line
447 string containing one subdirectory name per line; in that
448 case, `#`-comments are supported and tabs and spaces are ignored
449 (see "Most basic example usage" above.)
451 In each case the subdirectory should usually be a relative pathname;
452 it is relative to the directory containing `Cargo.nail`.
454 `[alt_cargolock]`: Alternative `Cargo.lock` filename
455 ----------------------------------------------------
457 To control use of alternative `Cargo.lock` filename, use the section
458 `[alt_cargolock]`. Settings here:
460 * `file = <some leafname>`.
462 * `file = true`: Equivalent to `file = "Cargo.lock.example"`.
463 (This is the default.)
465 * `file = false`: Disables this feature.
467 * `force = false`: Uses the alternative filename only if it
468 already exists. (This is the default.)
470 * `force = true`: Always uses the alternative filename.
472 `[oot]`: Out-of-tree build support
473 ----------------------------------
475 * `dir`: The build directory. If relative, it is relative to the
476 parent of the invocation directory (and could be a symlink then).
477 Default is `Build` (assuming `use` is specified).
479 The build directory will contain one subdir for each package: each
480 subdir in the build dir corresponds to one source dir where
481 nailing-cargo was invoked. nailing-cargo will arrange to create
482 these subdirectories, so the build directory can start out empty.
484 * `use`: How to become the build user. Needs to be combined
485 with other setting(s):
487 * `ssh`: Use ssh. `user` must be given as well and can be
488 a username on localhost, or the `<user>@<host>`
491 * `command_args`: `command` must be specified as a list,
492 specifying a command and arguments which work like `nice`.
494 * `command_sh`: `command` must be specified as a list,
495 specifying a command and arguments which work like `sh -c`.
497 * `null`: Run builds as the same user.
499 * `really`: Use `really` from `chiark-really.deb`.
500 `user` must be given as well.
502 * `disable': Disable this feature, even if `dir` is set.
504 * `command`: The command to run for `command_sh` or `command_args`.
506 In both cases, this is a command and its arguments/options. The
507 list will be passed to `execvp`. The difference between
508 `command_args` and `command_sh` is in what nailing-cargo appends to
509 the specified `command` list:
511 For `command_args`, nailing cargo appends multiple more arguments;
512 each one should be passed as-is as a single argument to the actual
513 build command. This is correct if `command` is a program like
514 `nice` or `really`, which takes a command and its arguments and
515 does not go via the shell.
517 For `command_sh`, nailing-cargo appends one single further
518 argument. That argument is a shell command; nailing-cargo
519 constructs it by shell-quoting the real command and arguments and
520 wrapping them up in a small script, the text of which becomes the
521 extra argument to `command`. This is correct if `command` will
522 pass its argument to a bournelike shell - for example, if `command`
523 is an ssh rune for a remote account whose shell is `/bin/sh` or
526 * `user`: The build username, for `really` and `ssh`. For `ssh`, can
527 be just the local username (meaning `@localhost`), or
530 `[arch]`: Architecture convenience aliases
531 ------------------------------------------
533 This is a map from archictecture aliases to full cargo architecture
534 names. The keys are the aliases; each entry should be a string, the
535 cargo architecture name.
537 Only keys starting with an ascii uppercase letter are relevant, since
538 other names are not looked up in this alias map.
540 `[misc]`: Miscellaneous individual nailing-cargo config
541 -------------------------------------------------------
543 * <a name="misc_online">`online`</a>:
545 Specifies whether to allow or prevent cargo from accessing the
546 network. Value is a boolean or `'auto'`. `'auto'` permits online
547 access if the cargo subcommand being invoked is one whose main
548 purpose involves online access.
550 Implemented by passing `--offline` to cargo when necessary ---
551 cargo's default is online. nailing-cargo's default is
557 * nailing-cargo temporarily dirties your source trees, including
558 particularly `Cargo.toml` and `Cargo.lock`; and if nailing-cargo
559 crashes or is interrupted these changes may be left behind.
560 Unfortunately it is not possible to avoid this temporary dirtying
561 because the cargo team have deliberately made cargo inflexible -
562 [issue#6715](https://github.com/rust-lang/cargo/issues/6715).
563 At least, running nailing-cargo again will clean up any mess
564 left by an interrupted run.
566 * nailing-cargo needs to understand the behaviour of the cargo
567 subcommand you are running - especially for out-of-tree builds.
568 nailing-cargo only has a short builtin list of commands it knows
569 about (see [`-s<subcommand`](#s_subcommand)). For other commands, you may need to
570 add an entry to `@subcmd_props` in the source, or use
571 [`--subcommand-props`](#subcommand_props).
573 Contributions of additonal entries to `@subcmd_props` (or bug
574 reports about missing entries) are of course very welcome.
576 * Out-of-tree builds ought to support `sudo`. Patches welcome.
578 * Out-of-tree builds require a unified filesystem view: eg, different
579 users on the same host, NFS, or something.
581 Specifically, the invocation and build execution environments must
582 both have visibility of the source and build directories, at the
583 same absolute pathnames. The invocation environment must be able
584 to write to the build environment (but vice versa is not
587 This could be improved.
589 * The alternative `Cargo.lock` filename must currently be a leafname. I
590 think fixing this just involves review to check other values work
593 * The alternative `Cargo.lock` file must be on the same filesystem
594 as the source tree. This is not so easy to fix; we would want the
595 existing algorithm but a fallback for the different-filsystem case.
597 * `Cargo.nail` is unconditionally looked for in the parent directory.
598 Ideally this should be configurable, and also perhaps be able to
599 combine multiple `Cargo.nail` files? Relatedly, although
600 nailing-cargo can read multiple config files, it can only handle
601 one file specifying directories and packages.
603 * nailing-cargo uses a single lockfile alongside your `Cargo.nail`,
604 rather than a more sophisticated scheme involving locking
605 particular directories. This means that if you run multiple
606 copies of nailing-cargo at once, in different directories, but
607 with `Cargo.nail` files which imply overlapping sets of package
608 directories, things will go Badly Wrong.
610 Contributing and legal
611 ======================
613 nailing-cargo is Free Software.
615 Please help improve it. Contributions (to address the limitations, or
616 to add new facilities to help work with cargo) are welcome by email to
617 `ijackson@chiark.greenend.org.uk` or via the [Salsa
618 project](https://salsa.debian.org/iwj/nailing-cargo).
620 If you plan to do substantial work, please do get in touch with a
621 sketch of your proposed changes.
626 This project accepts contributions based on the git commit
627 Signed-off-by convention, by which the contributors certify their
628 contributions according to the Developer Certificate of Origin version
629 1.1 - see the file DEVELOPER-CERTIFICATE.
631 Copyright (C) 2019-2020 Ian Jackson and others
633 This program is free software: you can redistribute it and/or modify
634 it under the terms of the GNU Affero General Public License as
635 published by the Free Software Foundation, either version 3 of the
636 License, or (at your option) any later version.
638 This program is distributed in the hope that it will be useful,
639 but WITHOUT ANY WARRANTY; without even the implied warranty of
640 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
641 GNU Affero General Public License for more details.
643 You should have received a copy of the GNU Affero General Public License
644 along with this program. If not, see <http://www.gnu.org/licenses/>.
646 Individual files generally contain the following tag in the copyright
647 notice, instead of the full licence grant text:
649 SPDX-License-Identifier: AGPL-3.0-or-later
651 As is conventional, this should be read as a licence grant.