--- sidebar_position: 1 description: Codex is building a decentralised durability storage engine --- # How to Use Codex > The Codex project aims to create a decentralised durability engine that allows persisting data in p2p networks. In other words, it allows storing files and data with predictable durability guarantees for later retrieval. > WARNING: This project is under active development and is considered pre-alpha. [![License: Apache](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT) [![Stability: experimental](https://img.shields.io/badge/stability-experimental-orange.svg)](#stability) [![CI](https://github.com/status-im/nim-codex/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/status-im/nim-codex/actions?query=workflow%3ACI+branch%3Amain) [![Codecov](https://codecov.io/gh/status-im/nim-codex/branch/main/graph/badge.svg?token=XFmCyPSNzW)](https://codecov.io/gh/status-im/nim-codex) [![Discord](https://img.shields.io/discord/895609329053474826)](https://discord.gg/CaJTh24ddQ) ## Build and run For detailed instructions on preparing to build nim-codex see [*Building Codex*](BUILDING.md). To build the project, clone it, and run: ```bash make update && make exec ``` The executable will be placed under the `build` directory under the project root. Run the client with: ```bash build/codex ``` ### CLI options ``` build/codex --help Usage: codex [OPTIONS]... command The following options are available: --log-level Sets the log level [=LogLevel.INFO]. --metrics Enable the metrics server [=false]. --metrics-address Listening address of the metrics server [=127.0.0.1]. --metrics-port Listening HTTP port of the metrics server [=8008]. -d, --data-dir The directory where codex will store configuration and data.. -l, --listen-port Specifies one or more listening ports for the node to listen on. [=0]. -i, --listen-ip The public IP [=0.0.0.0]. --udp-port Specify the discovery (UDP) port [=8090]. --net-privkey Source of network (secp256k1) private key file (random|) [=random]. -b, --bootstrap-node Specifies one or more bootstrap nodes to use when connecting to the network.. --max-peers The maximum number of peers to connect to [=160]. --agent-string Node agent string which is used as identifier in network [=Codex]. -p, --api-port The REST Api port [=8080]. -c, --cache-size The size in MiB of the block cache, 0 disables the cache [=100]. --persistence Enables persistence mechanism, requires an Ethereum node [=false]. --eth-provider The URL of the JSON-RPC API of the Ethereum node [=ws://localhost:8545]. --eth-account The Ethereum account that is used for storage contracts [=EthAddress.none]. --eth-deployment The json file describing the contract deployment [=string.none]. Available sub-commands: codex initNode ``` ### Example: Running two Codex clients ```bash build/codex --data-dir="$(pwd)/Codex1" -i=127.0.0.1 ``` This will start Codex with a data directory pointing to `Codex1` under the current execution directory and announce itself on the DHT under `127.0.0.1`. To run a second client that automatically discovers nodes on the network, we need to get the Signed Peer Record (SPR) of first client, Client1. We can do this by querying the `/info` endpoint of the node's REST API. `curl http://127.0.0.1:8080/api/codex/v1/info` This should output information about Client1, including its PeerID, TCP/UDP addresses, data directory, and SPR: ```json { "id": "16Uiu2HAm92LGXYTuhtLaZzkFnsCx6FFJsNmswK6o9oPXFbSKHQEa", "addrs": [ "/ip4/0.0.0.0/udp/8090", "/ip4/0.0.0.0/tcp/49336" ], "repo": "/repos/status-im/nim-codex/Codex1", "spr": "spr:CiUIAhIhAmqg5fVU2yxPStLdUOWgwrkWZMHW2MHf6i6l8IjA4tssEgIDARpICicAJQgCEiECaqDl9VTbLE9K0t1Q5aDCuRZkwdbYwd_qLqXwiMDi2ywQ5v2VlAYaCwoJBH8AAAGRAh-aGgoKCAR_AAABBts3KkcwRQIhAPOKl38CviplVbMVnA_9q3N1K_nk5oGuNp7DWeOqiJzzAiATQ2acPyQvPxLU9YS-TiVo4RUXndRcwMFMX2Yjhw8k3A" } ``` Now, let's start a second client, Client2. Because we're already using the default ports TCP (:8080) and UDP (:8090) for the first client, we have to specify new ports to avoid a collision. Additionally, we can specify the SPR from Client1 as the bootstrap node for discovery purposes, allowing Client2 to determine where content is located in the network. ```bash build/codex --data-dir="$(pwd)/Codex2" -i=127.0.0.1 --api-port=8081 --udp-port=8091 --bootstrap-node=spr:CiUIAhIhAmqg5fVU2yxPStLdUOWgwrkWZMHW2MHf6i6l8IjA4tssEgIDARpICicAJQgCEiECaqDl9VTbLE9K0t1Q5aDCuRZkwdbYwd_qLqXwiMDi2ywQ5v2VlAYaCwoJBH8AAAGRAh-aGgoKCAR_AAABBts3KkcwRQIhAPOKl38CviplVbMVnA_9q3N1K_nk5oGuNp7DWeOqiJzzAiATQ2acPyQvPxLU9YS-TiVo4RUXndRcwMFMX2Yjhw8k3A ``` There are now two clients running. We could upload a file to Client1 and download that file (given its CID) using Client2, by using the clients' REST API. ## Interacting with the client The client exposes a REST API that can be used to interact with the clients. These commands could be invoked with any HTTP client, however the following endpoints assume the use of the `curl` command. ### `/api/codex/v1/connect/{peerId}` Connect to a peer identified by its peer id. Takes an optional `addrs` parameter with a list of valid [multiaddresses](https://multiformats.io/multiaddr/). If `addrs` is absent, the peer will be discovered over the DHT. Example: ```bash curl "127.0.0.1:8080/api/codex/v1/connect/?addrs=" ``` ### `/api/codex/v1/download/{id}` Download data identified by a `Cid`. Example: ```bash curl -vvv "127.0.0.1:8080/api/codex/v1/download/" --output ``` ### `/api/codex/v1/upload` Upload a file, upon success returns the `Cid` of the uploaded file. Example: ```bash curl -vvv -H "content-type: application/octet-stream" -H Expect: -T "" "127.0.0.1:8080/api/codex/v1/upload" -X POST ``` ### `/api/codex/v1/info` Get useful node info such as its peer id, address, and SPR. Example: ```bash curl -vvv "127.0.0.1:8080/api/codex/v1/info" ```