allow specifying a dockerfile to use for a target

Author: Emilgardis

Diff for: CHANGELOG.md

@@ -10,7 +10,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - #795 - added images for additional toolchains maintained by cross-rs.
 - #792 - added `CROSS_CONTAINER_IN_CONTAINER` environment variable to replace `CROSS_DOCKER_IN_DOCKER`.
 - #782 - added `build-std` config option, which builds the rust standard library from source if enabled.
-- #775 - forward Cargo exit code to host
+- #678 - Add optional `target.{target}.dockerfile[.file]`, `target.{target}.dockerfile.context` and `target.{target}.dockerfile.build-args` to invoke docker/podman build before using an image.
+- #678 - Add `target.{target}.pre-build` config for running commands before building the image.
 - #772 - added `CROSS_CONTAINER_OPTS` environment variable to replace `DOCKER_OPTS`.
 - #767, #788 - added the `cross-util` and `xtask` commands.
 - #745 - added `thumbv7neon-*` targets.
@@ -27,6 +28,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Changed
 
+- #775 - forward Cargo exit code to host
 - #762 - re-enabled `x86_64-unknown-dragonfly` target.
 - #747 - reduced android image sizes.
 - #746 - limit image permissions for android images.

Diff for: Cargo.lock

@@ -31,6 +31,7 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 serde_ignored = "0.1.2"
 shell-words = "1.1.0"
+sha1_smol = "1.0.0"
 
 [target.'cfg(not(windows))'.dependencies]
 nix = { version = "0.24", default-features = false, features = ["user"] }

Diff for: Cargo.toml

@@ -112,10 +112,22 @@ the default one. Normal Docker behavior applies, so:
 
 - If only `tag` is omitted, then Docker will use the `latest` tag.
 
+#### Dockerfiles
+
+If you're using a custom Dockerfile, you can use `target.{{TARGET}}.dockerfile` to automatically build it
+
+``` toml
+[target.aarch64-unknown-linux-gnu.dockerfile]
+dockerfile = "./path/to/where/the/Dockerfile/resides"
+```
+
+`cross` will build and use the image that was built instead of the default image.
+
 It's recommended to base your custom image on the default Docker image that
 cross uses: `ghcr.io/cross-rs/{{TARGET}}:{{VERSION}}` (where `{{VERSION}}` is cross's version).
 This way you won't have to figure out how to install a cross C toolchain in your
-custom image. Example below:
+custom image.
+
 
 ``` Dockerfile
 FROM ghcr.io/cross-rs/aarch64-unknown-linux-gnu:latest
@@ -125,8 +137,23 @@ RUN dpkg --add-architecture arm64 && \
     apt-get install --assume-yes libfoo:arm64
 ```
 
+If you want cross to provide the `FROM` instruction, you can do the following
+
+``` Dockerfile
+ARG CROSS_BASE_IMAGE
+FROM $CROSS_BASE_IMAGE
+
+RUN ...
 ```
-$ docker build -t my/image:tag path/to/where/the/Dockerfile/resides
+
+#### Pre-build hook
+
+`cross` enables you to add dependencies and run other necessary commands in the image before using it.
+This action will be added to the used image, so it won't be ran/built every time you use `cross`.
+
+``` toml
+[target.x86_64-unknown-linux-gnu]
+pre-build = ["dpkg --add-architecture arm64 && apt-get update && apt-get install --assume-yes libfoo:arm64"]
 ```
 
 ### Docker in Docker

Diff for: README.md

@@ -1,6 +1,7 @@
 The `cross` configuration in the `Cross.toml` file, can contain the following elements:
 
 # `build`
+
 The `build` key allows you to set global variables, e.g.:
 
 ```toml
@@ -11,6 +12,7 @@ default-target = "x86_64-unknown-linux-gnu"
 ```
 
 # `build.env`
+
 With the `build.env` key you can globally set volumes that should be mounted
 in the Docker container or environment variables that should be passed through.
 For example:
@@ -22,17 +24,20 @@ passthrough = ["IMPORTANT_ENV_VARIABLES"]
 ```
 
 # `target.TARGET`
+
 The `target` key allows you to specify parameters for specific compilation targets.
 
 ```toml
 [target.aarch64-unknown-linux-gnu]
 xargo = false
 build-std = false
 image = "test-image"
+pre-build = ["echo 'Hello world!'"]
 runner = "custom-runner"
 ```
 
 # `target.TARGET.env`
+
 The `target` key allows you to specify environment variables that should be used for a specific compilation target.
 This is similar to `build.env`, but allows you to be more specific per target.
 
@@ -41,3 +46,19 @@ This is similar to `build.env`, but allows you to be more specific per target.
 volumes = ["VOL1_ARG", "VOL2_ARG"]
 passthrough = ["IMPORTANT_ENV_VARIABLES"]
 ```
+
+# `target.TARGET.dockerfile`
+
+```toml
+[target.x86_64-unknown-linux-gnu.dockerfile]
+file = "./Dockerfile"
+context = "."
+build-args = { ARG1 = "foo" }
+```
+
+also supports
+
+```toml
+[target.x86_64-unknown-linux-gnu]
+dockerfile = "./Dockerfile"
+```

Diff for: docs/cross_toml.md

@@ -186,7 +186,7 @@ fn remove_images(
     }
     command.args(images);
     if execute {
-        command.run(verbose).map_err(Into::into)
+        command.run(verbose, false).map_err(Into::into)
     } else {
         println!("{:?}", command);
         Ok(())

Diff for: src/bin/commands/images.rs

@@ -148,7 +148,9 @@ pub fn cargo_metadata_with_args(
 
 /// Pass-through mode
 pub fn run(args: &[String], verbose: bool) -> Result<ExitStatus, CommandError> {
-    Command::new("cargo").args(args).run_and_get_status(verbose)
+    Command::new("cargo")
+        .args(args)
+        .run_and_get_status(verbose, false)
 }
 
 /// run cargo and get the output, does not check the exit status

Diff for: src/cargo.rs

@@ -68,6 +68,23 @@ impl Environment {
         self.get_target_var(target, "IMAGE")
     }
 
+    fn dockerfile(&self, target: &Target) -> Option<String> {
+        let res = self.get_values_for("DOCKERFILE", target, |s| s.to_string());
+        res.0.or(res.1)
+    }
+
+    fn dockerfile_context(&self, target: &Target) -> Option<String> {
+        let res = self.get_values_for("DOCKERFILE_CONTEXT", target, |s| s.to_string());
+        res.0.or(res.1)
+    }
+
+    fn pre_build(&self, target: &Target) -> Option<Vec<String>> {
+        let res = self.get_values_for("PRE_BUILD", target, |v| {
+            v.split('\n').map(String::from).collect()
+        });
+        res.0.or(res.1)
+    }
+
     fn runner(&self, target: &Target) -> Option<String> {
         self.get_target_var(target, "RUNNER")
     }
@@ -179,15 +196,37 @@ impl Config {
         &self,
         target: &Target,
         env: impl Fn(&Environment, &Target) -> (Option<Vec<String>>, Option<Vec<String>>),
-        config_build: impl for<'a> Fn(&'a CrossToml) -> &'a [String],
-        config_target: impl for<'a> Fn(&'a CrossToml, &Target) -> &'a [String],
+        config: impl for<'a> Fn(&'a CrossToml, &Target) -> (&'a [String], &'a [String]),
+        sum: bool,
     ) -> Result<Vec<String>> {
+        let mut collected = vec![];
         let (env_build, env_target) = env(&self.env, target);
 
-        let mut collected = self.sum_of_env_toml_values(env_build, config_build)?;
-        collected.extend(self.sum_of_env_toml_values(env_target, |t| config_target(t, target))?);
+        if sum {
+            collected.extend(self.sum_of_env_toml_values(env_target, |t| config(t, target))?);
+            return Ok(collected);
+        } else if let Some(env_target) = env_target {
+            return Ok(env_target);
+        }
+
+        let (build, target) = self
+            .toml
+            .as_ref()
+            .map(|t| config(t, target))
+            .unwrap_or((&[], &[]));
 
-        Ok(collected)
+        // FIXME: let expression
+        if target.is_empty() {
+            if let Some(env_build) = env_build {
+                return Ok(env_build);
+            }
+        }
+
+        if target.is_empty() {
+            Ok(build.to_vec())
+        } else {
+            Ok(target.to_vec())
+        }
     }
 
     #[cfg(test)]
@@ -215,18 +254,13 @@ impl Config {
         self.vec_from_config(
             target,
             Environment::passthrough,
-            CrossToml::env_passthrough_build,
-            CrossToml::env_passthrough_target,
+            CrossToml::env_passthrough,
+            true,
         )
     }
 
     pub fn env_volumes(&self, target: &Target) -> Result<Vec<String>> {
-        self.vec_from_config(
-            target,
-            Environment::volumes,
-            CrossToml::env_volumes_build,
-            CrossToml::env_volumes_target,
-        )
+        self.vec_from_config(target, Environment::volumes, CrossToml::env_volumes, false)
     }
 
     pub fn target(&self, target_list: &TargetList) -> Option<Target> {
@@ -238,16 +272,48 @@ impl Config {
             .and_then(|t| t.default_target(target_list))
     }
 
+    pub fn dockerfile(&self, target: &Target) -> Result<Option<String>> {
+        self.string_from_config(target, Environment::dockerfile, CrossToml::dockerfile)
+    }
+
+    pub fn dockerfile_context(&self, target: &Target) -> Result<Option<String>> {
+        self.string_from_config(
+            target,
+            Environment::dockerfile_context,
+            CrossToml::dockerfile_context,
+        )
+    }
+
+    pub fn dockerfile_build_args(
+        &self,
+        target: &Target,
+    ) -> Result<Option<HashMap<String, String>>> {
+        // This value does not support env variables
+        self.toml
+            .as_ref()
+            .map_or(Ok(None), |t| Ok(t.dockerfile_build_args(target)))
+    }
+
+    pub fn pre_build(&self, target: &Target) -> Result<Vec<String>> {
+        self.vec_from_config(
+            target,
+            |e, t| (None, e.pre_build(t)),
+            CrossToml::pre_build,
+            false,
+        )
+    }
+
     fn sum_of_env_toml_values<'a>(
         &'a self,
         env_values: Option<Vec<String>>,
-        toml_getter: impl FnOnce(&'a CrossToml) -> &'a [String],
+        toml_getter: impl FnOnce(&'a CrossToml) -> (&'a [String], &'a [String]),
     ) -> Result<Vec<String>> {
         let mut collect = vec![];
         if let Some(mut vars) = env_values {
             collect.append(&mut vars);
         } else if let Some(toml_values) = self.toml.as_ref().map(toml_getter) {
-            collect.extend(toml_values.iter().cloned());
+            collect.extend(toml_values.0.iter().cloned());
+            collect.extend(toml_values.1.iter().cloned());
         }
 
         Ok(collect)
@@ -390,6 +456,7 @@ mod tests {
             let expected = vec!["VOLUME1".to_string(), "VOLUME2".into()];
 
             let result = config.env_volumes(&target()).unwrap();
+            dbg!(&result);
             assert!(result.len() == 2);
             assert!(result.contains(&expected[0]));
             assert!(result.contains(&expected[1]));