Native Rust HDFS client

This is a proof-of-concept HDFS client written natively in Rust. All other clients I have found in any other language are simply wrappers around libhdfs and require all the same Java dependencies, so I wanted to see if I could write one from scratch given that HDFS isn't really changing very often anymore. Several basic features are working, however it is not nearly as robust and the real HDFS client.

What this is not trying to do is implement all HDFS client/FileSystem interfaces, just things involving reading and writing data.

Supported HDFS features

Here is a list of currently supported and unsupported but possible future features.

HDFS Operations

• [x] Listing
• [x] Reading
• [x] Writing
• [x] Rename
• [x] Delete

HDFS Features

• [x] Name Services
• [ ] Observer reads (state ID tracking is supported, but needs improvements on tracking Observer/Active NameNode)
• [ ] Federated router
• [ ] Erasure coding

Security Features

• [x] Kerberos authentication (GSSAPI SASL support)
• [x] Token authentication (DIGEST-MD5 SASL support, no encryption support)
• [x] NameNode SASL connection
• [ ] DataNode SASL connection
• [ ] DataNode data transfer encryption
• [ ] Encryption at rest (KMS support)

Other improvements

• [ ] Better error handling
• [ ] RPC retries
• [x] Async support

Building

Mac

``` brew install gsasl krb5

You might need these env vars on newer Macs

export BINDGENEXTRACLANGARGS="-I/opt/homebrew/include" export LIBRARYPATH=/opt/homebrew/lib cargo build --all-features ```

Ubuntu

apt-get install clang libkrb5-dev libgsasl-dev cargo build --all-features

Crate features

• token - enables token based DIGEST-MD5 authentication support. This uses the gsasl native library and only supports authentication, not integrity or confidentiality
• kerberos - enables kerberos GSSAPI authentication support. This uses the libgssapi crate and supports integrity as well as confidentiality
• object_store - provides an object_store wrapper around the HDFS client
• protobuf-src - builds protobuf from source to avoid having to pre-install it