runner: unpack dependencies only once

Reuse unpacked dependencies across multiple tasks by mounting them into
a single task's build directory. We lose support for file conflict
detection for now.

1 files changed, 15 insertions, 3 deletions

diff --git a/crates/runner/src/paths.rs b/crates/runner/src/paths.rs
index 5e183cb..2e174df 100644
--- a/crates/runner/src/paths.rs
+++ b/crates/runner/src/paths.rs
@@ -28,14 +28,14 @@
 //! └── tmp/                          # temporary files (cleaned on start)
 //!     ├── dev/                      # container /dev
 //!     ├── rootfs/                   # unpacked rootfs.tar
+//!     ├── depends/                  # unpacked dependencies
 //!     └── task/
 //!         └── <input hash>/
 //!             ├── build/            # mount point for /build directory
 //!             │   ├── downloads/    # downloaded sources
 //!             │   ├── task/         # internal runner files
 //!             │   └── work/         # build overlay mountpoint
-//!             ├── rootfs/           # rootfs overlay mountpoint
-//!             └── depends/          # overlayed on rootfs in container
+//!             └── rootfs/           # rootfs overlay mountpoint
 //! ```
 
 use common::string_hash::*;
@@ -47,10 +47,10 @@ pub const DOWNLOADS_DIR: &str = "build/downloads";
 pub const TMP_DIR: &str = "build/tmp";
 pub const DEV_DIR: &str = "build/tmp/dev";
 pub const ROOTFS_DIR: &str = "build/tmp/rootfs";
+pub const DEPENDS_TMP_DIR: &str = "build/tmp/depends";
 pub const TASK_TMP_DIR: &str = "build/tmp/task";
 
 pub const TASK_TMP_ROOTFS_SUBDIR: &str = "rootfs";
-pub const TASK_TMP_DEPENDS_SUBDIR: &str = "depends";
 
 pub const LOCKFILE: &str = "build/build.lock";
 pub const OUTPUT_STATE_DIR: &str = "build/state/output";
@@ -97,6 +97,18 @@ pub fn layer_dir(hash: &LayerHash) -> String {
 	join(&[LAYER_STATE_DIR, &hash.to_string()])
 }
 
+pub fn depend_tmp_dir(hash: &ArchiveHash) -> String {
+	join(&[DEPENDS_TMP_DIR, &hash.to_string()])
+}
+
+pub fn depend_dir(hash: &ArchiveHash) -> String {
+	join(&[DEPENDS_TMP_DIR, &hash.to_string()])
+}
+
+pub fn depend_lock_filename(hash: &ArchiveHash) -> String {
+	join(&[DEPENDS_TMP_DIR, &format!("{}.lock", hash.to_string())])
+}
+
 pub fn archive_tmp_filename(hash: &InputHash) -> String {
 	join(&[OUTPUT_STATE_DIR, &format!("{}.tar.tmp", hash)])
 }