feat: add copilot-persistence feature

.github/workflows/release.yaml

@@ -18,7 +18,7 @@ jobs:
         with:
           publish-features: "true"
           base-path-to-features: "./src"
-          generate-docs: "true"
+          generate-docs: "false"
 
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/test.yaml

@@ -16,6 +16,7 @@ jobs:
           - ohmyposh
           - microsoft-security-devops-cli
           - prompty-dumpty
+          - copilot-persistence
         baseImage:
           - debian:latest
           - ubuntu:latest
@@ -38,6 +39,7 @@ jobs:
           - ohmyposh
           - microsoft-security-devops-cli
           - prompty-dumpty
+          - copilot-persistence
     steps:
       - uses: actions/checkout@v4
 

README.md

@@ -80,6 +80,32 @@ guardian init --force
 
 Note: `guardian init` requires a git repository, so it must be run manually after the container starts (not during feature installation).
 
+### Copilot CLI Persistence
+
+Persists GitHub Copilot CLI settings and chat history across container rebuilds using a named Docker volume.
+
+**Usage:**
+
+```json
+{
+  "features": {
+    "ghcr.io/devcontainers/features/copilot-cli:1": {},
+    "ghcr.io/rosstaco/devcontainer-features/copilot-persistence:1": {}
+  }
+}
+```
+
+**How It Works:**
+- Mounts a named volume (scoped per dev container) to `/copilot-data`
+- Creates a symlink from `~/.copilot` → `/copilot-data`
+- Sets the `COPILOT_DATA_DIR` environment variable to `/copilot-data`
+
+**What Persists:**
+- Chat history and sessions
+- CLI configuration (model preferences, settings)
+- Command history
+- Trusted folders
+
 ## Publishing
 
 This repository uses a **GitHub Action** [workflow](.github/workflows/release.yaml) that publishes each Feature to GHCR (GitHub Container Registry).

src/copilot-persistence/README.md

@@ -0,0 +1,49 @@
+# Copilot CLI Persistence Feature
+
+This devcontainer feature persists GitHub Copilot CLI settings and chat history across container rebuilds.
+
+## How It Works
+
+Inspired by the [shell-history pattern](https://github.com/stuartleeks/dev-container-features/tree/main/src/shell-history), this feature:
+
+1. **Mounts a named volume** (scoped per dev container via `${devcontainerId}`) to `/copilot-data`
+2. **Creates a symlink** from `~/.copilot` → `/copilot-data`
+3. **Sets ownership** to the container user during installation (auto-detects from `$_REMOTE_USER`)
+
+
+## What Persists
+
+- ✅ Chat history and sessions
+- ✅ CLI configuration (model preferences, settings)
+- ✅ Command history
+- ✅ Trusted folders
+
+## Usage
+
+```json
+{
+  "features": {
+    "ghcr.io/devcontainers/features/copilot-cli:1": {},
+    "ghcr.io/rosstaco/devcontainer-features/copilot-persistence:1": {}
+  }
+}
+```
+
+## Benefits Over Direct Mount
+
+- No permission conflicts (volume created in neutral location)
+- Works even if Copilot CLI has XDG_CONFIG_HOME bugs
+- Clean lifecycle management during feature install
+- Easy to share across projects
+
+## Troubleshooting
+
+View the volume data:
+```bash
+ls -la /copilot-data
+```
+
+Check the symlink:
+```bash
+ls -la ~/.copilot
+```

src/copilot-persistence/devcontainer-feature.json

@@ -0,0 +1,20 @@
+{
+  "id": "copilot-persistence",
+  "version": "1.0.0",
+  "name": "Copilot CLI Persistence",
+  "documentationURL": "https://github.com/rosstaco/devcontainer-features/tree/main/src/copilot-persistence",
+  "description": "Persists GitHub Copilot CLI settings and chat history across rebuilds",
+  "mounts": [
+    {
+      "source": "${devcontainerId}-copilot-data",
+      "target": "/copilot-data",
+      "type": "volume"
+    }
+  ],
+  "installsAfter": [
+    "ghcr.io/devcontainers/features/copilot-cli"
+  ],
+  "containerEnv": {
+    "COPILOT_DATA_DIR": "/copilot-data"
+  }
+}

src/copilot-persistence/install.sh

@@ -0,0 +1,64 @@
+#!/bin/bash
+set -e
+
+echo "Setting up Copilot CLI persistence..."
+
+# Determine the user (defaults to vscode if not set)
+USERNAME="${_REMOTE_USER:-"${USERNAME:-"vscode"}"}"
+
+# Resolve home directory via the passwd database or shell expansion
+USER_HOME=""
+if command -v getent >/dev/null 2>&1; then
+    USER_HOME="$(getent passwd "${USERNAME}" | cut -d: -f6)"
+fi
+if [ -z "${USER_HOME}" ]; then
+    USER_HOME="$(eval echo "~${USERNAME}" 2>/dev/null || true)"
+fi
+if [ -z "${USER_HOME}" ]; then
+    echo "Error: Unable to determine home directory for user '${USERNAME}'" >&2
+    exit 1
+fi
+
+# Create the persistent data directory in a neutral location
+mkdir -p /copilot-data
+
+# Get the user's UID and GID
+USER_UID=$(id -u "${USERNAME}" 2>/dev/null || echo "1000")
+USER_GID=$(id -g "${USERNAME}" 2>/dev/null || echo "1000")
+
+# Fix ownership for the user (build-time, may be overridden by volume mount)
+chown -R "${USER_UID}:${USER_GID}" /copilot-data
+chmod 700 /copilot-data
+
+# Create an init script that fixes volume permissions at container start.
+# When a named volume is mounted, build-time permissions may not carry over,
+# so we fix ownership on every shell login.
+mkdir -p /usr/local/share/copilot-persistence
+cat > /usr/local/share/copilot-persistence/init.sh << 'INIT'
+#!/bin/bash
+# Fix /copilot-data ownership if it exists and is not writable by current user
+if [ -d /copilot-data ] && [ ! -w /copilot-data ]; then
+    sudo chown -R "$(id -u):$(id -g)" /copilot-data 2>/dev/null || true
+fi
+INIT
+chmod 755 /usr/local/share/copilot-persistence/init.sh
+
+# Source the init script from profile so it runs on container start
+cat > /etc/profile.d/copilot-persistence.sh << 'PROFILE'
+# Fix copilot-data volume permissions on login
+if [ -f /usr/local/share/copilot-persistence/init.sh ]; then
+    . /usr/local/share/copilot-persistence/init.sh
+fi
+PROFILE
+
+# Create a symlink from the default location to our persistent volume
+# This handles the case where Copilot doesn't use XDG_CONFIG_HOME correctly
+mkdir -p "${USER_HOME}"
+if [ ! -L "${USER_HOME}/.copilot" ] || [ "$(readlink "${USER_HOME}/.copilot")" != "/copilot-data" ]; then
+    rm -rf "${USER_HOME}/.copilot" 2>/dev/null || true
+    ln -sf /copilot-data "${USER_HOME}/.copilot"
+    chown -h "${USER_UID}:${USER_GID}" "${USER_HOME}/.copilot"
+fi
+
+echo "Copilot CLI persistence configured successfully for user: ${USERNAME}"
+echo "Data will be stored in /copilot-data (mounted volume)"

test/copilot-persistence/debian.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+# Scenario test: Debian base image
+# Validates copilot-persistence works on Debian
+
+set -e
+
+source dev-container-features-test-lib
+
+# Run the init script to fix volume permissions (normally runs via /etc/profile.d on login)
+if [ -f /usr/local/share/copilot-persistence/init.sh ]; then
+    . /usr/local/share/copilot-persistence/init.sh
+fi
+
+check "copilot-data directory exists" test -d /copilot-data
+
+check "COPILOT_DATA_DIR is set" test "$COPILOT_DATA_DIR" = "/copilot-data"
+
+check "symlink exists at ~/.copilot" test -L ~/.copilot
+
+check "can write to copilot-data" bash -c "touch /copilot-data/test-file && rm /copilot-data/test-file"
+
+reportResults

test/copilot-persistence/scenarios.json

@@ -0,0 +1,14 @@
+{
+    "debian": {
+        "image": "mcr.microsoft.com/devcontainers/base:debian",
+        "features": {
+            "copilot-persistence": {}
+        }
+    },
+    "ubuntu": {
+        "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
+        "features": {
+            "copilot-persistence": {}
+        }
+    }
+}

test/copilot-persistence/test.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+
+# This test file will be executed against an auto-generated devcontainer.json that
+# includes the 'copilot-persistence' Feature with no options.
+#
+# Eg:
+# {
+#    "image": "<..some-base-image...>",
+#    "features": {
+#       "copilot-persistence": {}
+#    }
+# }
+#
+# Thus, the value of all options will fall back to the default value in the
+# Feature's 'devcontainer-feature.json'.
+
+set -e
+
+# Optional: Import test library bundled with the devcontainer CLI
+source dev-container-features-test-lib
+
+# Run the init script to fix volume permissions (normally runs via /etc/profile.d on login)
+if [ -f /usr/local/share/copilot-persistence/init.sh ]; then
+    . /usr/local/share/copilot-persistence/init.sh
+fi
+
+# Feature-specific tests
+
+check "init script exists" test -f /usr/local/share/copilot-persistence/init.sh
+
+check "profile.d script exists" test -f /etc/profile.d/copilot-persistence.sh
+
+check "copilot-data directory exists" test -d /copilot-data
+
+check "copilot-data directory is writable" test -w /copilot-data
+
+check "COPILOT_DATA_DIR env var is set" test -n "$COPILOT_DATA_DIR"
+
+check "COPILOT_DATA_DIR points to /copilot-data" test "$COPILOT_DATA_DIR" = "/copilot-data"
+
+check "symlink exists at ~/.copilot" test -L ~/.copilot
+
+check "symlink target is /copilot-data" test "$(readlink ~/.copilot)" = "/copilot-data"
+
+# Report results
+reportResults

test/copilot-persistence/ubuntu.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+# Scenario test: Ubuntu base image
+# Validates copilot-persistence works on Ubuntu
+
+set -e
+
+source dev-container-features-test-lib
+
+# Run the init script to fix volume permissions (normally runs via /etc/profile.d on login)
+if [ -f /usr/local/share/copilot-persistence/init.sh ]; then
+    . /usr/local/share/copilot-persistence/init.sh
+fi
+
+check "copilot-data directory exists" test -d /copilot-data
+
+check "COPILOT_DATA_DIR is set" test "$COPILOT_DATA_DIR" = "/copilot-data"
+
+check "symlink exists at ~/.copilot" test -L ~/.copilot
+
+check "can write to copilot-data" bash -c "touch /copilot-data/test-file && rm /copilot-data/test-file"
+
+reportResults