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|
//! Client to the Obnam server HTTP API.
use crate::chunk::{
ClientTrust, ClientTrustError, DataChunk, GenerationChunk, GenerationChunkError,
};
use crate::chunkid::ChunkId;
use crate::chunkmeta::ChunkMeta;
use crate::chunkstore::{ChunkStore, StoreError};
use crate::cipher::{CipherEngine, CipherError};
use crate::config::{ClientConfig, ClientConfigError};
use crate::generation::{FinishedGeneration, GenId, LocalGeneration, LocalGenerationError};
use crate::genlist::GenerationList;
use crate::label::Label;
use log::{error, info};
use std::fs::File;
use std::io::prelude::*;
use std::path::{Path, PathBuf};
/// Possible errors when using the server API.
#[derive(Debug, thiserror::Error)]
pub enum ClientError {
/// No chunk id for uploaded chunk.
#[error("Server response claimed it had created a chunk, but lacked chunk id")]
NoCreatedChunkId,
/// Server claims to not have an entity.
#[error("Server does not have {0}")]
NotFound(String),
/// Server does not have a chunk.
#[error("Server does not have chunk {0}")]
ChunkNotFound(ChunkId),
/// Server does not have generation.
#[error("Server does not have generation {0}")]
GenerationNotFound(ChunkId),
/// Server didn't give us a chunk's metadata.
#[error("Server response did not have a 'chunk-meta' header for chunk {0}")]
NoChunkMeta(ChunkId),
/// Chunk has wrong checksum and may be corrupted.
#[error("Wrong checksum for chunk {0}, got {1}, expected {2}")]
WrongChecksum(ChunkId, String, String),
/// Client configuration is wrong.
#[error(transparent)]
ClientConfigError(#[from] ClientConfigError),
/// An error encrypting or decrypting chunks.
#[error(transparent)]
CipherError(#[from] CipherError),
/// An error regarding generation chunks.
#[error(transparent)]
GenerationChunkError(#[from] GenerationChunkError),
/// An error regarding client trust.
#[error(transparent)]
ClientTrust(#[from] ClientTrustError),
/// An error using a backup's local metadata.
#[error(transparent)]
LocalGenerationError(#[from] LocalGenerationError),
/// An error with the `chunk-meta` header.
#[error("couldn't convert response chunk-meta header to string: {0}")]
MetaHeaderToString(reqwest::header::ToStrError),
/// An error from the HTTP library.
#[error("error from reqwest library: {0}")]
ReqwestError(reqwest::Error),
/// Couldn't look up a chunk via checksum.
#[error("lookup by chunk checksum failed: {0}")]
ChunkExists(reqwest::Error),
/// Error parsing JSON.
#[error("failed to parse JSON: {0}")]
JsonParse(serde_json::Error),
/// Error generating JSON.
#[error("failed to generate JSON: {0}")]
JsonGenerate(serde_json::Error),
/// Error parsing YAML.
#[error("failed to parse YAML: {0}")]
YamlParse(serde_yaml::Error),
/// Failed to open a file.
#[error("failed to open file {0}: {1}")]
FileOpen(PathBuf, std::io::Error),
/// Failed to create a file.
#[error("failed to create file {0}: {1}")]
FileCreate(PathBuf, std::io::Error),
/// Failed to write a file.
#[error("failed to write to file {0}: {1}")]
FileWrite(PathBuf, std::io::Error),
/// Error from a chunk store.
#[error(transparent)]
ChunkStore(#[from] StoreError),
}
/// Client for the Obnam server HTTP API.
pub struct BackupClient {
store: ChunkStore,
cipher: CipherEngine,
}
impl BackupClient {
/// Create a new backup client.
pub fn new(config: &ClientConfig) -> Result<Self, ClientError> {
info!("creating backup client with config: {:#?}", config);
let pass = config.passwords()?;
Ok(Self {
store: ChunkStore::remote(config)?,
cipher: CipherEngine::new(&pass),
})
}
/// Does the server have a chunk?
pub async fn has_chunk(&self, meta: &ChunkMeta) -> Result<Option<ChunkId>, ClientError> {
let mut ids = self.store.find_by_label(meta).await?;
Ok(ids.pop())
}
/// Upload a data chunk to the server.
pub async fn upload_chunk(&mut self, chunk: DataChunk) -> Result<ChunkId, ClientError> {
let enc = self.cipher.encrypt_chunk(&chunk)?;
let data = enc.ciphertext().to_vec();
let id = self.store.put(data, chunk.meta()).await?;
Ok(id)
}
/// Get current client trust chunk from repository, if there is one.
pub async fn get_client_trust(&self) -> Result<Option<ClientTrust>, ClientError> {
let ids = self.find_client_trusts().await?;
let mut latest: Option<ClientTrust> = None;
for id in ids {
let chunk = self.fetch_chunk(&id).await?;
let new = ClientTrust::from_data_chunk(&chunk)?;
if let Some(t) = &latest {
if new.timestamp() > t.timestamp() {
latest = Some(new);
}
} else {
latest = Some(new);
}
}
Ok(latest)
}
async fn find_client_trusts(&self) -> Result<Vec<ChunkId>, ClientError> {
let label = Label::literal("client-trust");
let meta = ChunkMeta::new(&label);
let ids = self.store.find_by_label(&meta).await?;
Ok(ids)
}
/// List backup generations known by the server.
pub fn list_generations(&self, trust: &ClientTrust) -> GenerationList {
let finished = trust
.backups()
.iter()
.map(|id| FinishedGeneration::new(&format!("{}", id), ""))
.collect();
GenerationList::new(finished)
}
/// Fetch a data chunk from the server, given the chunk identifier.
pub async fn fetch_chunk(&self, chunk_id: &ChunkId) -> Result<DataChunk, ClientError> {
let (body, meta) = self.store.get(chunk_id).await?;
let meta_bytes = meta.to_json_vec();
let chunk = self.cipher.decrypt_chunk(&body, &meta_bytes)?;
Ok(chunk)
}
async fn fetch_generation_chunk(&self, gen_id: &GenId) -> Result<GenerationChunk, ClientError> {
let chunk = self.fetch_chunk(gen_id.as_chunk_id()).await?;
let gen = GenerationChunk::from_data_chunk(&chunk)?;
Ok(gen)
}
/// Fetch a backup generation's metadata, given it's identifier.
pub async fn fetch_generation(
&self,
gen_id: &GenId,
dbname: &Path,
) -> Result<LocalGeneration, ClientError> {
let gen = self.fetch_generation_chunk(gen_id).await?;
// Fetch the SQLite file, storing it in the named file.
let mut dbfile = File::create(dbname)
.map_err(|err| ClientError::FileCreate(dbname.to_path_buf(), err))?;
for id in gen.chunk_ids() {
let chunk = self.fetch_chunk(id).await?;
dbfile
.write_all(chunk.data())
.map_err(|err| ClientError::FileWrite(dbname.to_path_buf(), err))?;
}
info!("downloaded generation to {}", dbname.display());
let gen = LocalGeneration::open(dbname)?;
Ok(gen)
}
}
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