Merge #1325

1325: create CACHEDIR.TAG during custom docker build r=Emilgardis a=vaffeine

Closes #1324.

Co-authored-by: Vladyslav Aleksashyn <vaffeine@users.noreply.github.com>

.changes/1325.json

@@ -0,0 +1,5 @@
+{
+    "description": "create CACHEDIR.TAG during custom docker build",
+    "type": "fixed",
+    "issues": [1324]
+}

src/docker/custom.rs

@@ -7,7 +7,10 @@ use crate::shell::MessageInfo;
 use crate::{errors::*, file, CommandExt, ToUtf8};
 use crate::{CargoMetadata, TargetTriple};
 
-use super::{get_image_name, path_hash, BuildCommandExt, BuildResultExt, Engine, ImagePlatform};
+use super::{
+    create_target_dir, get_image_name, path_hash, BuildCommandExt, BuildResultExt, Engine,
+    ImagePlatform,
+};
 
 pub const CROSS_CUSTOM_DOCKERFILE_IMAGE_PREFIX: &str = "localhost/cross-rs/cross-custom-";
 
@@ -119,11 +122,12 @@ impl<'a> Dockerfile<'a> {
         let path = match self {
             Dockerfile::File { path, .. } => PathBuf::from(path),
             Dockerfile::Custom { content, .. } => {
-                let path = paths
+                let target_dir = paths
                     .metadata
                     .target_directory
-                    .join(options.target.to_string())
-                    .join(format!("Dockerfile.{}-custom", &options.target));
+                    .join(options.target.to_string());
+                create_target_dir(&target_dir)?;
+                let path = target_dir.join(format!("Dockerfile.{}-custom", &options.target));
                 {
                     let mut file = file::write_file(&path, true)?;
                     file.write_all(content.as_bytes())?;

src/docker/shared.rs

@@ -819,7 +819,7 @@ const CACHEDIR_TAG: &str = "Signature: 8a477f597d28d172789f06886806bc55
 # This file is a cache directory tag created by cross.
 # For information about cache directory tags see https://bford.info/cachedir/";
 
-fn create_target_dir(path: &Path) -> Result<()> {
+pub fn create_target_dir(path: &Path) -> Result<()> {
     // cargo creates all paths to the target directory, and writes
     // a cache dir tag only if the path doesn't previously exist.
     if !path.exists() {