Simple Object Storage

Introduction

Simple Object Storage is a very simple C++ webserver which provides a store of tagged binary objects (the objects can be large), which are available over http.

Read access is public. Write access is controlled by tokens.

Public read actions:

Retrieve Object

• Objects are accessed via a label and tag, or via their hash. For example:
  • wget http://localhost:8123/object/squashkiwi:latest
  • wget http://localhost:8123/object/4528400792837739857

Check Object Existence

• Check if an object exists by label:tag or hash:
  • curl http://localhost:8123/exists/squashkiwi:latest
  • curl http://localhost:8123/exists/4528400792837739857

Retrieve Hash

• Get the hash for a given label and tag:
  • curl http://localhost:8123/hash/squashkiwi:latest
  • Response format: {"result":"success","hash":"4528400792837739857"}

List Store Contents

• Get a full list of {label:tag,hash} entries:
  • curl http://localhost:8123/dir
  • Response format: {"result":"success","entries":[{"label_tag":"example:latest","hash":"4528400792837739857"}]}

Retrieve Metadata

• Get all metadata for a tag:
  • curl http://localhost:8123/meta/squashkiwi:latest
  • Response format: {"result":"success","metadata":{"description":"Example file","tags":["test","example"],"custom_field":"custom value"}}

Service Status Check

• Quick status check:
  • curl http://localhost:8123/status
  • Response format: {"result":"success","status":"ok"}

Write actions (require authentication):

Upload Object

• Upload a file with metadata (via HTTP PUT):

curl -X PUT \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -F "file=@/path/to/your/file.txt" \
  -F 'metadata={"labeltag":"example:latest","description":"Example file","tags":["test","example"],"custom_field":"custom value"}' \
  "http://localhost:8123/upload"

• The object file is uploaded, hashed, added to the registry (if that hash doesn't already exist), and {label:tag,hash} entries are added to the directory index.
• Matching tags on older versions are removed.
• Response format: {"result":"success","hash":"4528400792837739857"}

Delete Object

• Delete an object and all its tags:
  • curl -H "Authorization: Bearer YOUR_TOKEN" http://localhost:8123/deleteobject?hash=4528400792837739857
  • Response format: {"result":"success"}

Configuration

• The server is configured via ~/.config/simple_object_storage/config.json which allows setting:
  • write_tokens: List of valid write access tokens
  • object_store_path: Location for the object store (path on disk)
  • host: Server host (default: "0.0.0.0")
  • port: Server port (default: 8123)

Example config.json:

{
    "write_tokens": ["your-secret-token-1", "your-secret-token-2"],
    "object_store_path": "/data/storage",
    "host": "0.0.0.0",
    "port": 8123
}

Signal Handling

The server handles the following signals:

• SIGTERM/SIGINT: Gracefully shuts down the server when received (e.g. from Ctrl+C or system shutdown)
• SIGHUP: Reloads the server configuration without restarting the service

The server ensures proper cleanup of resources during shutdown, including:

• Closing all database connections
• Stopping the HTTP server
• Cleaning up any open file handles
• Properly terminating worker threads

Dockcross is used to cross-build for both 64-bit x86 and arm64 (combining both into one docker container image).