sync

Reviewed-on: #18
Co-authored-by: Timo Behrendt <t.behrendt@t00n.de>
Co-committed-by: Timo Behrendt <t.behrendt@t00n.de>

.gitea/workflows/ci.yaml

@@ -22,3 +22,12 @@ jobs:
           provenance: false
           tags: |
             backupsidecar:ci-test
+
+  check-syntax:
+    name: Check syntax
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - name: Check syntax
+        run: |
+          bash -n src/backup.sh

Dockerfile

@@ -7,6 +7,10 @@ RUN apk update && apk add --no-cache \
     postgresql-client \
     jq
 
+RUN curl -O https://dl.min.io/client/mc/release/linux-amd64/mc \
+    && chmod +x mc \
+    && mv mc /usr/local/bin/
+
 WORKDIR /app
 
 COPY src/backup.sh /app/backup.sh

README.md

@@ -1,6 +1,6 @@
 # BackupSidecar
 
-BackupSidecar is a lightweight backup solution designed to run as a cron job in Kubernetes. It automates backups using Restic and supports both directory and PostgreSQL database backups. Notifications are sent via Gotify to keep you informed of backup results.
+BackupSidecar is a lightweight backup and restore solution designed to run as a cron job in Kubernetes. It automates backups and restores using Restic and supports both directory and PostgreSQL database operations. Optional notifications can be sent via Gotify to keep you informed of operation results.
 
 ## Configuration
 
@@ -8,34 +8,69 @@ BackupSidecar is configured through environment variables. Below is a breakdown
 
 ### General Settings
 
-These variables apply to both directory and PostgreSQL backups.
+These variables apply to both backup and restore operations.
 
-- **`BACKUP_MODE`** _(optional)_ - Defines the backup type (`directory` or `postgres`). Defaults to `directory`.
+- **`OPERATION_MODE`** _(optional)_ - Defines the operation type (`backup` or `restore`). Defaults to `backup`.
+- **`BACKUP_MODE`** _(optional)_ - Defines the backup type (`directory`, `postgres`, or `s3`). Defaults to `directory`.
 - **`RESTIC_PASSWORD`** _(required)_ - The encryption password for Restic.
 - **`RESTIC_REPOSITORY`** _(required)_ - The URI of the Restic repository (e.g., `rest:http://your-rest-server:8000/backup`).
 - **`RESTIC_REST_USERNAME`** _(optional)_ - The username for REST server authentication.
 - **`RESTIC_REST_PASSWORD`** _(optional)_ - The password for REST server authentication.
-- **`GOTIFYHOST`** _(required)_ - The Gotify server URL.
-- **`GOTIFYTOKEN`** _(required)_ - The API token for Gotify.
-- **`GOTIFYTOPIC`** _(required)_ - The topic under which backup notifications will be sent.
+- **`ENABLE_GOTIFY`** _(optional)_ - Enable Gotify notifications. Set to `true` to enable, any other value or unset disables notifications. Defaults to `true`.
+- **`GOTIFYHOST`** _(required when ENABLE_GOTIFY=true)_ - The Gotify server URL.
+- **`GOTIFYTOKEN`** _(required when ENABLE_GOTIFY=true)_ - The API token for Gotify.
+- **`GOTIFYTOPIC`** _(required when ENABLE_GOTIFY=true)_ - The topic under which backup notifications will be sent.
 
-### Directory Backup
+### Directory Operations
 
-When running in `directory` mode, the following variable must be set:
+When running in `directory` mode, the following variables must be set:
+
+**For Backup Operations:**
 
 - **`SOURCEDIR`** _(required)_ - The path of the directory to be backed up.
 
-### PostgreSQL Backup
+**For Restore Operations:**
+
+- **`RESTOREDIR`** _(required)_ - The path where files should be restored to.
+- **`RESTORE_SNAPSHOT_ID`** _(optional)_ - The specific snapshot ID to restore (defaults to `latest`).
+
+### PostgreSQL Operations
 
 For `postgres` mode, the following database-related variables are required:
 
+**Common Variables:**
+
 - **`PGHOST`** _(required)_ - The hostname of the PostgreSQL server.
-- **`PGDATABASE`** _(required)_ - The name of the database to back up.
+- **`PGDATABASE`** _(required)_ - The name of the database.
 - **`PGUSER`** _(required)_ - The PostgreSQL username.
 - **`PGPORT`** _(optional)_ - The port for PostgreSQL (defaults to `5432`).
 - **`PGPASSWORD`** _(optional)_ - The password for authentication. Setting this prevents interactive prompts.
+
+**Backup-Specific Variables:**
+
 - **`PG_DUMP_ARGS`** _(optional)_ - Additional flags for `pg_dump`.
 
+**Restore-Specific Variables:**
+
+- **`RESTORE_SNAPSHOT_ID`** _(optional)_ - The specific snapshot ID to restore (defaults to `latest`).
+- **`PSQL_ARGS`** _(optional)_ - Additional flags for `psql` (e.g., `--single-transaction`).
+
+### S3 Operations
+
+For `s3` mode, the following S3-related variables are required:
+
+**Common Variables:**
+
+- **`S3_BUCKET`** _(required)_ - The name of the S3 bucket to backup/restore.
+- **`S3_ENDPOINT`** _(required)_ - The S3 endpoint URL (e.g., `http://minio:9000` for MinIO).
+- **`MINIO_ACCESS_KEY`** _(required)_ - The MinIO access key for S3 authentication.
+- **`MINIO_SECRET_KEY`** _(required)_ - The MinIO secret key for S3 authentication.
+- **`S3_PREFIX`** _(optional)_ - Optional path prefix within the bucket to backup/restore.
+
+**Restore-Specific Variables:**
+
+- **`RESTORE_SNAPSHOT_ID`** _(optional)_ - The specific snapshot ID to restore (defaults to `latest`).
+
 ## Dependencies
 
 Ensure the following commands are available in the container:
@@ -43,10 +78,14 @@ Ensure the following commands are available in the container:
 - `restic`
 - `curl`
 - `jq`
-- `pg_dump` _(only required for `postgres` mode)_
+- `pg_dump` _(only required for PostgreSQL backup operations)_
+- `psql` _(only required for PostgreSQL restore operations)_
+- `mc` _(only required for S3 operations)_
 
 ## Usage
 
+### Backup Operations
+
 Example Kubernetes CronJob manifest for running BackupSidecar as a cron job for directory backups in minimal configuration:
 
 ```yaml
@@ -82,6 +121,8 @@ spec:
                   value: "directory" # or "postgres"
                 - name: SOURCEDIR
                   value: "/data/source"
+                - name: ENABLE_GOTIFY
+                  value: "true"
                 - name: GOTIFYHOST
                   value: "http://gotify.example.com"
                 - name: GOTIFYTOKEN
@@ -102,12 +143,230 @@ spec:
                 claimName: source-data-pvc
 ```
 
+### Restore Operations
+
+Example Kubernetes Job manifest for running BackupSidecar to restore a directory:
+
+```yaml
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: backupsidecar-restore
+  namespace: authentik
+spec:
+  backoffLimit: 3
+  activeDeadlineSeconds: 600
+  template:
+    spec:
+      restartPolicy: OnFailure
+      containers:
+        - name: backupsidecar
+          image: backupsidecar:latest
+          env:
+            - name: OPERATION_MODE
+              value: "restore"
+            - name: BACKUP_MODE
+              value: "directory"
+            - name: RESTOREDIR
+              value: "/data/restore"
+            - name: RESTORE_SNAPSHOT_ID
+              value: "abc123def456" # optional, defaults to latest
+            - name: RESTIC_REPOSITORY
+              value: "rest:http://rest-server:8000/backup"
+            - name: RESTIC_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: restic_password
+            - name: GOTIFYHOST
+              value: "http://gotify.example.com"
+            - name: GOTIFYTOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: gotify_token
+            - name: GOTIFYTOPIC
+              value: "Restore Notification"
+          volumeMounts:
+            - name: restore-data
+              mountPath: /data/restore
+      volumes:
+        - name: restore-data
+          persistentVolumeClaim:
+            claimName: restore-data-pvc
+```
+
+Example Kubernetes Job manifest for running BackupSidecar to restore a PostgreSQL database:
+
+```yaml
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: backupsidecar-postgres-restore
+  namespace: authentik
+spec:
+  backoffLimit: 3
+  activeDeadlineSeconds: 600
+  template:
+    spec:
+      restartPolicy: OnFailure
+      containers:
+        - name: backupsidecar
+          image: backupsidecar:latest
+          env:
+            - name: OPERATION_MODE
+              value: "restore"
+            - name: BACKUP_MODE
+              value: "postgres"
+            - name: PGHOST
+              value: "postgres.example.com"
+            - name: PGDATABASE
+              value: "mydatabase"
+            - name: PGUSER
+              value: "myuser"
+            - name: PGPASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: postgres-secret
+                  key: password
+            - name: PGPORT
+              value: "5432"
+            - name: RESTORE_SNAPSHOT_ID
+              value: "abc123def456" # optional, defaults to latest
+            - name: PSQL_ARGS
+              value: "--single-transaction" # optional
+            - name: RESTIC_REPOSITORY
+              value: "rest:http://rest-server:8000/backup"
+            - name: RESTIC_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: restic_password
+            - name: GOTIFYHOST
+              value: "http://gotify.example.com"
+            - name: GOTIFYTOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: gotify_token
+            - name: GOTIFYTOPIC
+              value: "Database Restore Notification"
+```
+
+Example Kubernetes Job manifest for running BackupSidecar to backup an S3 bucket:
+
+```yaml
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: backupsidecar-s3-backup
+  namespace: authentik
+spec:
+  backoffLimit: 3
+  activeDeadlineSeconds: 600
+  template:
+    spec:
+      restartPolicy: OnFailure
+      containers:
+        - name: backupsidecar
+          image: backupsidecar:latest
+          env:
+            - name: OPERATION_MODE
+              value: "backup"
+            - name: BACKUP_MODE
+              value: "s3"
+            - name: S3_BUCKET
+              value: "my-bucket"
+            - name: S3_ENDPOINT
+              value: "http://minio:9000"
+            - name: S3_PREFIX
+              value: "data" # optional
+            - name: MINIO_ACCESS_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: minio-secret
+                  key: access_key
+            - name: MINIO_SECRET_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: minio-secret
+                  key: secret_key
+            - name: RESTIC_REPOSITORY
+              value: "rest:http://rest-server:8000/backup"
+            - name: RESTIC_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: restic_password
+            - name: GOTIFYHOST
+              value: "http://gotify.example.com"
+            - name: GOTIFYTOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: gotify_token
+            - name: GOTIFYTOPIC
+              value: "S3 Backup Notification"
+```
+
+Example Kubernetes Job manifest for running BackupSidecar to restore an S3 bucket:
+
+```yaml
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: backupsidecar-s3-restore
+  namespace: authentik
+spec:
+  backoffLimit: 3
+  activeDeadlineSeconds: 600
+  template:
+    spec:
+      restartPolicy: OnFailure
+      containers:
+        - name: backupsidecar
+          image: backupsidecar:latest
+          env:
+            - name: OPERATION_MODE
+              value: "restore"
+            - name: BACKUP_MODE
+              value: "s3"
+            - name: S3_BUCKET
+              value: "my-bucket"
+            - name: S3_ENDPOINT
+              value: "http://minio:9000"
+            - name: S3_PREFIX
+              value: "data" # optional
+            - name: RESTORE_SNAPSHOT_ID
+              value: "abc123def456" # optional, defaults to latest
+            - name: MINIO_ACCESS_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: minio-secret
+                  key: access_key
+            - name: MINIO_SECRET_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: minio-secret
+                  key: secret_key
+            - name: RESTIC_REPOSITORY
+              value: "rest:http://rest-server:8000/backup"
+            - name: RESTIC_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: restic_password
+            - name: GOTIFYHOST
+              value: "http://gotify.example.com"
+            - name: GOTIFYTOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: backupsidecar-secret
+                  key: gotify_token
+            - name: GOTIFYTOPIC
+              value: "S3 Restore Notification"
+```
+
 ## Notifications
 
-The script sends success or failure notifications via Gotify.
-
-Example success notification:
-
-```
-Backup successful. Snapshot 56ff6a909a44e01f67d2d88f9a76aa713d437809d7ed14a2361e28893f38befb: files new: 1, files changed: 0, data added: 1019 bytes in 0.277535184 sec
-```
+The script can send success or failure notifications via Gotify when enabled. To enable notifications, set `ENABLE_GOTIFY=true` and provide the required Gotify configuration variables (`GOTIFYHOST`, `GOTIFYTOKEN`, `GOTIFYTOPIC`). When notifications are disabled, backup status messages are still logged to the console.

src/backup.sh

@@ -1,71 +1,6 @@
 #!/bin/bash
 set -euo pipefail
 
-#######################################
-# Determine backup mode from the environment only.
-# Valid values: "directory" or "postgres".
-# Default to "directory" if not provided.
-#######################################
-BACKUP_MODE="${BACKUP_MODE:-directory}"
-
-#######################################
-# Check for required external commands.
-#######################################
-REQUIRED_CMDS=(restic curl jq)
-if [ "$BACKUP_MODE" = "postgres" ]; then
-    REQUIRED_CMDS+=(pg_dump)
-fi
-
-for cmd in "${REQUIRED_CMDS[@]}"; do
-    if ! command -v "$cmd" &>/dev/null; then
-        echo "Error: Required command '$cmd' is not installed." >&2
-        exit 1
-    fi
-done
-
-#######################################
-# Validate common required environment variables.
-#######################################
-# Gotify notification settings.
-: "${GOTIFYHOST:?Environment variable GOTIFYHOST is not set}"
-: "${GOTIFYTOKEN:?Environment variable GOTIFYTOKEN is not set}"
-: "${GOTIFYTOPIC:?Environment variable GOTIFYTOPIC is not set}"
-
-# Restic encryption password.
-: "${RESTIC_PASSWORD:?Environment variable RESTIC_PASSWORD is not set}"
-
-# Use the repository URI directly from the environment.
-# Example: export RESTIC_REPOSITORY="rest:http://your-rest-server:8000/backup"
-: "${RESTIC_REPOSITORY:?Environment variable RESTIC_REPOSITORY is not set}"
-
-#######################################
-# Validate mode-specific environment variables.
-#######################################
-case "$BACKUP_MODE" in
-    directory)
-        : "${SOURCEDIR:?Environment variable SOURCEDIR is not set (required for directory backup mode)}"
-        ;;
-    postgres)
-        : "${PGHOST:?Environment variable PGHOST is not set (required for PostgreSQL backup mode)}"
-        : "${PGDATABASE:?Environment variable PGDATABASE is not set (required for PostgreSQL backup mode)}"
-        : "${PGUSER:?Environment variable PGUSER is not set (required for PostgreSQL backup mode)}"
-        # Optional: default PGPORT to 5432.
-        : "${PGPORT:=5432}"
-        if [ -z "${PGPASSWORD:-}" ]; then
-            echo "Warning: Environment variable PGPASSWORD is not set. pg_dump may fail if authentication is required."
-        fi
-        ;;
-    *)
-        echo "Error: Unknown backup mode '$BACKUP_MODE'. Valid modes are 'directory' and 'postgres'." >&2
-        exit 1
-        ;;
-esac
-
-#######################################
-# Build the Gotify URL.
-#######################################
-GOTIFYURL="${GOTIFYHOST}/message?token=${GOTIFYTOKEN}"
-
 #######################################
 # Date format for logging.
 #######################################
@@ -80,6 +15,121 @@ log() {
     echo "$(date +"$LOG_DATE_FORMAT") - $*"
 }
 
+#######################################
+# Determine operation mode from the environment only.
+# Valid values: "backup" or "restore".
+# Default to "backup" if not provided.
+#######################################
+OPERATION_MODE="${OPERATION_MODE:-backup}"
+
+#######################################
+# Determine backup mode from the environment only.
+# Valid values: "directory", "postgres", or "s3".
+# Default to "directory" if not provided.
+#######################################
+BACKUP_MODE="${BACKUP_MODE:-directory}"
+
+#######################################
+# Check for required external commands.
+#######################################
+REQUIRED_CMDS=(restic curl jq)
+if [ "$BACKUP_MODE" = "postgres" ]; then
+    if [ "$OPERATION_MODE" = "backup" ]; then
+        REQUIRED_CMDS+=(pg_dump)
+    elif [ "$OPERATION_MODE" = "restore" ]; then
+        REQUIRED_CMDS+=(psql)
+    fi
+elif [ "$BACKUP_MODE" = "s3" ]; then
+    REQUIRED_CMDS+=(mc)
+fi
+
+for cmd in "${REQUIRED_CMDS[@]}"; do
+    if ! command -v "$cmd" &>/dev/null; then
+        log "Error: Required command '$cmd' is not installed."
+        exit 1
+    fi
+done
+
+#######################################
+# Validate common required environment variables.
+#######################################
+# Gotify notification settings (optional).
+# Set ENABLE_GOTIFY to "true" to enable notifications, any other value or unset disables them.
+ENABLE_GOTIFY="${ENABLE_GOTIFY:-true}"
+
+if [ "$ENABLE_GOTIFY" = "true" ]; then
+    : "${GOTIFYHOST:?Environment variable GOTIFYHOST is not set (required when ENABLE_GOTIFY=true)}"
+    : "${GOTIFYTOKEN:?Environment variable GOTIFYTOKEN is not set (required when ENABLE_GOTIFY=true)}"
+    : "${GOTIFYTOPIC:?Environment variable GOTIFYTOPIC is not set (required when ENABLE_GOTIFY=true)}"
+else
+    log "Gotify notifications disabled. Backup status will be logged to console only."
+fi
+
+# Restic encryption password.
+: "${RESTIC_PASSWORD:?Environment variable RESTIC_PASSWORD is not set}"
+
+# Use the repository URI directly from the environment.
+# Example: export RESTIC_REPOSITORY="rest:http://your-rest-server:8000/backup"
+: "${RESTIC_REPOSITORY:?Environment variable RESTIC_REPOSITORY is not set}"
+
+#######################################
+# Validate operation mode.
+#######################################
+case "$OPERATION_MODE" in
+    backup|restore)
+        ;;
+    *)
+        echo "Error: Unknown operation mode '$OPERATION_MODE'. Valid modes are 'backup' and 'restore'." >&2
+        exit 1
+        ;;
+esac
+
+#######################################
+# Validate mode-specific environment variables.
+#######################################
+case "$BACKUP_MODE" in
+    directory)
+        if [ "$OPERATION_MODE" = "backup" ]; then
+            : "${SOURCEDIR:?Environment variable SOURCEDIR is not set (required for directory backup mode)}"
+        elif [ "$OPERATION_MODE" = "restore" ]; then
+            : "${RESTOREDIR:?Environment variable RESTOREDIR is not set (required for directory restore mode)}"
+        fi
+        ;;
+    postgres)
+        : "${PGHOST:?Environment variable PGHOST is not set (required for PostgreSQL mode)}"
+        : "${PGDATABASE:?Environment variable PGDATABASE is not set (required for PostgreSQL mode)}"
+        : "${PGUSER:?Environment variable PGUSER is not set (required for PostgreSQL mode)}"
+        # Optional: default PGPORT to 5432.
+        : "${PGPORT:=5432}"
+        if [ -z "${PGPASSWORD:-}" ]; then
+            if [ "$OPERATION_MODE" = "backup" ]; then
+                echo "Warning: Environment variable PGPASSWORD is not set. pg_dump may fail if authentication is required."
+            elif [ "$OPERATION_MODE" = "restore" ]; then
+                echo "Warning: Environment variable PGPASSWORD is not set. psql may fail if authentication is required."
+            fi
+        fi
+        ;;
+    s3)
+        : "${S3_BUCKET:?Environment variable S3_BUCKET is not set (required for S3 mode)}"
+        : "${S3_ENDPOINT:?Environment variable S3_ENDPOINT is not set (required for S3 mode)}"
+        : "${MINIO_ACCESS_KEY:?Environment variable MINIO_ACCESS_KEY is not set (required for S3 mode)}"
+        : "${MINIO_SECRET_KEY:?Environment variable MINIO_SECRET_KEY is not set (required for S3 mode)}"
+        # Optional: S3 path prefix
+        : "${S3_PREFIX:=}"
+        ;;
+    *)
+        echo "Error: Unknown backup mode '$BACKUP_MODE'. Valid modes are 'directory', 'postgres', and 's3'." >&2
+        exit 1
+        ;;
+esac
+
+#######################################
+# Build the Gotify URL (only if Gotify is enabled).
+#######################################
+if [ "$ENABLE_GOTIFY" = "true" ]; then
+    GOTIFYURL="${GOTIFYHOST}/message?token=${GOTIFYTOKEN}"
+fi
+
 #######################################
 # Send a notification via Gotify.
 # Arguments:
@@ -87,6 +137,13 @@ log() {
 #######################################
 send_notification() {
     local message="$1"
+    
+    # Only send notification if Gotify is enabled
+    if [ "$ENABLE_GOTIFY" != "true" ]; then
+        log "$message"
+        return 0
+    fi
+    
     if ! curl -s -X POST "$GOTIFYURL" -F "title=${GOTIFYTOPIC}" -F "message=${message}" >/dev/null; then
         log "Warning: Failed to send notification with message: ${message}"
     fi
@@ -157,6 +214,174 @@ backup_postgres() {
     run_restic_backup "${TEMP_BACKUP_DIR}"
 }
 
+#######################################
+# Run the restore using restic.
+# Arguments:
+#   $1 - The target directory to restore to.
+#   $2 - Optional snapshot ID to restore (defaults to latest).
+#######################################
+run_restic_restore() {
+    local target_dir="$1"
+    local snapshot_id="$2"
+    
+    log "Starting restore from repository ${RESTIC_REPOSITORY} to '${target_dir}'"
+    log "Using snapshot: ${snapshot_id}"
+    
+    # Create target directory if it doesn't exist
+    mkdir -p "${target_dir}"
+    
+    # Capture both stdout and stderr in a variable
+    restore_output=$(restic -r "${RESTIC_REPOSITORY}" restore "${snapshot_id}" --target "${target_dir}" --no-cache --json --verbose 2>&1)
+    # Optionally, also print the output to the console:
+    echo "$restore_output"
+    
+    # Parse the JSON lines output for the summary message
+    summary=$(echo "$restore_output" | jq -r 'select(.message_type=="summary") | "Restore completed: " + (.files_restored|tostring) + " files restored, " + (.bytes_restored|tostring) + " bytes in " + (.total_duration|tostring) + " sec"' 2>/dev/null || echo "Restore completed")
+    
+    # Check exit code of restic restore
+    if [ $? -eq 0 ]; then
+        msg="Restore successful. $summary"
+        log "$msg"
+        send_notification "$msg"
+    else
+        exit_code=$?
+        msg="Restore failed with error code ${exit_code}. $restore_output"
+        log "$msg"
+        send_notification "$msg"
+        exit "$exit_code"
+    fi
+}
+
+#######################################
+# Restore a directory (regular mode).
+#######################################
+restore_directory() {
+    local snapshot_id="${RESTORE_SNAPSHOT_ID:-latest}"
+    run_restic_restore "${RESTOREDIR}" "${snapshot_id}"
+}
+
+#######################################
+# Restore a PostgreSQL database.
+# Restores the database dump from the backup and applies it to the database.
+#######################################
+restore_postgres() {
+    local snapshot_id="${RESTORE_SNAPSHOT_ID:-latest}"
+    log "Starting PostgreSQL restore for database '${PGDATABASE}' on host '${PGHOST}'"
+    
+    # Create a temporary directory for the restore.
+    TEMP_RESTORE_DIR=$(mktemp -d)
+    log "Created temporary directory: ${TEMP_RESTORE_DIR}"
+
+    # Restore the backup to the temporary directory
+    run_restic_restore "${TEMP_RESTORE_DIR}" "${snapshot_id}"
+    
+    local dump_file="${TEMP_RESTORE_DIR}/dump.sql"
+    if [ ! -f "${dump_file}" ]; then
+        local msg="PostgreSQL restore failed. Database dump file not found at ${dump_file}"
+        log "$msg"
+        send_notification "$msg"
+        exit 1
+    fi
+    
+    log "Restoring PostgreSQL database from ${dump_file}..."
+    if psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${PGDATABASE}" ${PSQL_ARGS:-} < "${dump_file}"; then
+        local msg="PostgreSQL database restored successfully"
+        log "$msg"
+        send_notification "$msg"
+    else
+        local exit_code=$?
+        local msg="PostgreSQL restore failed with error code ${exit_code}"
+        log "$msg"
+        send_notification "$msg"
+        exit "$exit_code"
+    fi
+}
+
+#######################################
+# Backup an S3 bucket.
+# Syncs the S3 bucket to a temporary directory and then backs it up.
+#######################################
+backup_s3() {
+    log "Starting S3 backup for bucket '${S3_BUCKET}' at endpoint '${S3_ENDPOINT}'"
+    
+    # Create a temporary directory for the S3 sync.
+    TEMP_BACKUP_DIR=$(mktemp -d)
+    log "Created temporary directory: ${TEMP_BACKUP_DIR}"
+
+    # Configure MinIO Client alias
+    local alias_name="backupsidecar"
+    if ! mc alias set "${alias_name}" "${S3_ENDPOINT}" "${MINIO_ACCESS_KEY}" "${MINIO_SECRET_KEY}"; then
+        local msg="Failed to configure MinIO client alias"
+        log "$msg"
+        send_notification "$msg"
+        exit 1
+    fi
+
+    # Build S3 path
+    local s3_path="${alias_name}/${S3_BUCKET}"
+    if [ -n "${S3_PREFIX}" ]; then
+        s3_path="${s3_path}/${S3_PREFIX}"
+    fi
+
+    log "Syncing S3 bucket from ${s3_path} to ${TEMP_BACKUP_DIR}..."
+    if mc mirror "${s3_path}" "${TEMP_BACKUP_DIR}" --remove; then
+        log "S3 sync completed successfully."
+    else
+        local exit_code=$?
+        local msg="S3 sync failed with error code ${exit_code}"
+        log "$msg"
+        send_notification "$msg"
+        exit "$exit_code"
+    fi
+
+    # Back up the directory containing the S3 content.
+    run_restic_backup "${TEMP_BACKUP_DIR}"
+}
+
+#######################################
+# Restore an S3 bucket.
+# Restores the S3 content from the backup and syncs it back to S3.
+#######################################
+restore_s3() {
+    local snapshot_id="${RESTORE_SNAPSHOT_ID:-latest}"
+    log "Starting S3 restore for bucket '${S3_BUCKET}' at endpoint '${S3_ENDPOINT}'"
+    
+    # Create a temporary directory for the restore.
+    TEMP_RESTORE_DIR=$(mktemp -d)
+    log "Created temporary directory: ${TEMP_RESTORE_DIR}"
+
+    # Restore the backup to the temporary directory
+    run_restic_restore "${TEMP_RESTORE_DIR}" "${snapshot_id}"
+
+    # Configure MinIO Client alias
+    local alias_name="backupsidecar"
+    if ! mc alias set "${alias_name}" "${S3_ENDPOINT}" "${MINIO_ACCESS_KEY}" "${MINIO_SECRET_KEY}"; then
+        local msg="Failed to configure MinIO client alias"
+        log "$msg"
+        send_notification "$msg"
+        exit 1
+    fi
+
+    # Build S3 path
+    local s3_path="${alias_name}/${S3_BUCKET}"
+    if [ -n "${S3_PREFIX}" ]; then
+        s3_path="${s3_path}/${S3_PREFIX}"
+    fi
+
+    log "Syncing restored content from ${TEMP_RESTORE_DIR} to ${s3_path}..."
+    if mc mirror "${TEMP_RESTORE_DIR}" "${s3_path}" --remove; then
+        local msg="S3 restore completed successfully"
+        log "$msg"
+        send_notification "$msg"
+    else
+        local exit_code=$?
+        local msg="S3 restore failed with error code ${exit_code}"
+        log "$msg"
+        send_notification "$msg"
+        exit "$exit_code"
+    fi
+}
+
 #######################################
 # Cleanup temporary resources.
 #######################################
@@ -165,6 +390,10 @@ cleanup() {
         rm -rf "${TEMP_BACKUP_DIR}"
         log "Removed temporary directory ${TEMP_BACKUP_DIR}"
     fi
+    if [ -n "${TEMP_RESTORE_DIR:-}" ] && [ -d "${TEMP_RESTORE_DIR}" ]; then
+        rm -rf "${TEMP_RESTORE_DIR}"
+        log "Removed temporary directory ${TEMP_RESTORE_DIR}"
+    fi
 }
 trap cleanup EXIT
 
@@ -172,12 +401,32 @@ trap cleanup EXIT
 # Main routine.
 #######################################
 main() {
-    case "$BACKUP_MODE" in
-        directory)
-            backup_directory
+    case "$OPERATION_MODE" in
+        backup)
+            case "$BACKUP_MODE" in
+                directory)
+                    backup_directory
+                    ;;
+                postgres)
+                    backup_postgres
+                    ;;
+                s3)
+                    backup_s3
+                    ;;
+            esac
             ;;
-        postgres)
-            backup_postgres
+        restore)
+            case "$BACKUP_MODE" in
+                directory)
+                    restore_directory
+                    ;;
+                postgres)
+                    restore_postgres
+                    ;;
+                s3)
+                    restore_s3
+                    ;;
+            esac
             ;;
     esac
 }