# Codex Decentralized Durability Engine > The Codex project aims to create a decentralized 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/codex-storage/nim-codex/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/codex-storage/nim-codex/actions/workflows/ci.yml?query=branch%3Amaster) [![Docker](https://github.com/codex-storage/nim-codex/actions/workflows/docker.yml/badge.svg?branch=master)](https://github.com/codex-storage/nim-codex/actions/workflows/docker.yml?query=branch%3Amaster) [![Codecov](https://codecov.io/gh/codex-storage/nim-codex/branch/master/graph/badge.svg?token=XFmCyPSNzW)](https://codecov.io/gh/codex-storage/nim-codex) [![Discord](https://img.shields.io/discord/895609329053474826)](https://discord.gg/CaJTh24ddQ) ![Docker Pulls](https://img.shields.io/docker/pulls/codexstorage/nim-codex) ## 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 ``` The executable will be placed under the `build` directory under the project root. Run the client with: ```bash build/codex ``` ## Configuration It is possible to configure a Codex node in several ways: 1. CLI options 2. Env. variable 3. Config The order of priority is the same as above: Cli arguments > Env variables > Config file values. ### Environment variables In order to set a configuration option using environment variables, first find the desired CLI option and then transform it in the following way: 1. prepend it with `CODEX_` 2. make it uppercase 3. replace `-` with `_` For example, to configure `--log-level`, use `CODEX_LOG_LEVEL` as the environment variable name. ### Configuration file A [TOML](https://toml.io/en/) configuration file can also be used to set configuration values. Configuration option names and corresponding values are placed in the file, separated by `=`. Configuration option names can be obtained from the `codex --help` command, and should not include the `--` prefix. For example, a node's log level (`--log-level`) can be configured using TOML as follows: ```toml log-level = "trace" ``` The Codex node can then read the configuration from this file using the `--config-file` CLI parameter, like `codex --config-file=/path/to/your/config.toml`. ### CLI Options ``` build/codex --help Usage: codex [OPTIONS]... command The following options are available: --config-file Loads the configuration from a TOML file [=none]. --log-level Sets the log level [=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.. -i, --listen-addrs Multi Addresses to listen on [=/ip4/0.0.0.0/tcp/0]. -a, --nat IP Addresses to announce behind a NAT [=127.0.0.1]. -e, --disc-ip Discovery listen address [=0.0.0.0]. -u, --disc-port Discovery (UDP) port [=8090]. --net-privkey Source of network (secp256k1) private key file path or name [=key]. -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]. --api-bindaddr The REST API bind address [=127.0.0.1]. -p, --api-port The REST Api port [=8080]. --repo-kind backend for main repo store (fs, sqlite) [=fs]. -q, --storage-quota The size of the total storage quota dedicated to the node [=8589934592]. -t, --block-ttl Default block timeout in seconds - 0 disables the ttl [=$DefaultBlockTtl]. --block-mi Time interval in seconds - determines frequency of block maintenance cycle: how often blocks are checked for expiration and cleanup. [=$DefaultBlockMaintenanceInterval]. --block-mn Number of blocks to check every maintenance cycle. [=1000]. -c, --cache-size The size in MiB of the block cache, 0 disables the cache - might help on slow hardrives [=0]. --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]. --validator Enables validator, requires an Ethereum node [=false]. --validator-max-slots Maximum number of slots that the validator monitors [=1000]. Available sub-commands: codex initNode ``` #### Logging Codex uses [Chronicles](https://github.com/status-im/nim-chronicles) logging library, which allows great flexibility in working with logs. Chronicles has the concept of topics, which categorize log entries into semantic groups. Using the `log-level` parameter, you can set the top-level log level like `--log-level="trace"`, but more importantly, you can set log levels for specific topics like `--log-level="info; trace: marketplace,node; error: blockexchange"`, which sets the top-level log level to `info` and then for topics `marketplace` and `node` sets the level to `trace` and so on. ### Example: running two Codex clients To get acquainted with Codex, consider running the manual two-client test described [HERE](docs/TWOCLIENTTEST.md). ## API The client exposes a REST API that can be used to interact with the clients. Overview of the API can be found on [api.codex.storage](https://api.codex.storage).