From 884c1c01d4b6b9a3d4ca31d355409f19b7627068 Mon Sep 17 00:00:00 2001
From: Ben Taylor <me@taybenlor.com>
Date: Mon, 22 Jan 2024 22:28:23 +1100
Subject: [PATCH] Add layering for OCI (#290)

---
 packages/runtime/lib/elements/container.ts |  9 ++++++-
 packages/runtime/lib/elements/terminal.ts  |  9 ++++++-
 packages/runtime/lib/elements/wasi.ts      |  9 ++++++-
 packages/runtime/lib/oci.ts                | 31 +++++++++++++++++++---
 packages/runtime/lib/provider.ts           | 18 +++++++++++--
 5 files changed, 67 insertions(+), 9 deletions(-)

diff --git a/packages/runtime/lib/elements/container.ts b/packages/runtime/lib/elements/container.ts
index 05866b3..93ecbed 100644
--- a/packages/runtime/lib/elements/container.ts
+++ b/packages/runtime/lib/elements/container.ts
@@ -211,7 +211,14 @@ export class ContainerElement extends HTMLElement {
         return { resultType: "terminated" };
       }
       console.error(e);
-      this.terminal.write(`\nRunno crashed: ${e}`);
+      if (
+        e != null &&
+        (e instanceof Error || (typeof e === "object" && "message" in e))
+      ) {
+        this.terminal.write(
+          `\n[Crashed] ${(e as any).type ?? "Error"}: ${e.message}\n`
+        );
+      }
       return { resultType: "crash", error: makeRunnoError(e) };
     } finally {
       this.workerHost = undefined;
diff --git a/packages/runtime/lib/elements/terminal.ts b/packages/runtime/lib/elements/terminal.ts
index f63ee8a..d8d0bb8 100644
--- a/packages/runtime/lib/elements/terminal.ts
+++ b/packages/runtime/lib/elements/terminal.ts
@@ -120,7 +120,14 @@ export class TerminalElement extends HTMLElement {
         return { resultType: "terminated" };
       }
       console.error(e);
-      this.terminal.write(`\nRunno crashed: ${e}`);
+      if (
+        e != null &&
+        (e instanceof Error || (typeof e === "object" && "message" in e))
+      ) {
+        this.terminal.write(
+          `\n[Crashed] ${(e as any).type ?? "Error"}: ${e.message}\n`
+        );
+      }
       return { resultType: "crash", error: makeRunnoError(e) };
     } finally {
       this.workerHost = undefined;
diff --git a/packages/runtime/lib/elements/wasi.ts b/packages/runtime/lib/elements/wasi.ts
index 585f2db..406e343 100644
--- a/packages/runtime/lib/elements/wasi.ts
+++ b/packages/runtime/lib/elements/wasi.ts
@@ -227,7 +227,14 @@ export class WASIElement extends HTMLElement {
         return { resultType: "terminated" };
       }
       console.error(e);
-      this.terminal.write(`\nRunno crashed: ${e}`);
+      if (
+        e != null &&
+        (e instanceof Error || (typeof e === "object" && "message" in e))
+      ) {
+        this.terminal.write(
+          `\n[Crashed] ${(e as any).type ?? "Error"}: ${e.message}\n`
+        );
+      }
       return { resultType: "crash", error: makeRunnoError(e) };
     } finally {
       this.workerHost = undefined;
diff --git a/packages/runtime/lib/oci.ts b/packages/runtime/lib/oci.ts
index 9760724..a4604b7 100644
--- a/packages/runtime/lib/oci.ts
+++ b/packages/runtime/lib/oci.ts
@@ -11,11 +11,9 @@ type OCIContext = {
 export async function extractOCIFile(binary: Uint8Array): Promise<OCIContext> {
   const contents = await extractTarGz(binary);
 
-  // TODO: throw if the file doesn't exist or whatever
   const manifestFile = contents["/manifest.json"];
   const manifest = fileToJSON(manifestFile)[0];
 
-  // TODO: throw if the file doesn't exist or whatever
   const configPath = manifest["Config"];
 
   const config = fileToJSON(contents[`/${configPath}`]);
@@ -33,9 +31,34 @@ export async function extractOCIFile(binary: Uint8Array): Promise<OCIContext> {
     })
   );
 
-  // TODO: Implement the OCI spec for layering
+  // OCI spec for layering includes whiteout / deleting files
   // https://github.com/opencontainers/image-spec/blob/main/layer.md
-  const fs = layers.reduce((prev, current) => ({ ...prev, ...current }), {});
+  const fs = layers.reduce((prev, current) => {
+    // Whiteout files must be applied first
+
+    const entries = Object.entries(current);
+    for (const [path] of entries) {
+      if (path.endsWith(".wh..wh..opq")) {
+        // Opaque whiteout, delete all siblings
+        const prefix = path.replace(".wh..wh..opq", "");
+        for (const [existingPath] of Object.entries(prev)) {
+          if (existingPath.startsWith(prefix)) {
+            delete prev[existingPath];
+          }
+        }
+      } else if (path.includes(".wh.")) {
+        // Regular whiteout - just delete this one file
+        const filename = path.replace(".wh.", "");
+        delete prev[filename];
+      }
+    }
+
+    const currentWithoutWhiteouts = Object.fromEntries(
+      entries.filter(([p]) => !p.includes(".wh."))
+    );
+
+    return { ...prev, ...currentWithoutWhiteouts };
+  }, {});
 
   return {
     fs,
diff --git a/packages/runtime/lib/provider.ts b/packages/runtime/lib/provider.ts
index 5ff1126..60f50aa 100644
--- a/packages/runtime/lib/provider.ts
+++ b/packages/runtime/lib/provider.ts
@@ -81,7 +81,14 @@ export class RunnoProvider implements RuntimeMethods {
       fs = prepare.fs;
     } catch (e) {
       console.error(e);
-      this.terminal.terminal.write(`\nRunno crashed: ${e}\n`);
+      if (
+        e != null &&
+        (e instanceof Error || (typeof e === "object" && "message" in e))
+      ) {
+        this.terminal.terminal.write(
+          `\n[Crashed] ${(e as any).type ?? "Error"}: ${e.message}\n`
+        );
+      }
 
       return {
         resultType: "crash",
@@ -102,7 +109,14 @@ export class RunnoProvider implements RuntimeMethods {
         fs = { ...fs, ...baseFS };
       } catch (e) {
         console.error(e);
-        this.terminal.terminal.write(`\nRunno crashed: ${e}\n`);
+        if (
+          e != null &&
+          (e instanceof Error || (typeof e === "object" && "message" in e))
+        ) {
+          this.terminal.terminal.write(
+            `\n[Crashed] ${(e as any).type ?? "Error"}: ${e.message}\n`
+          );
+        }
 
         return {
           resultType: "crash",