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use garage_util::config::Config;
use garage_util::crdt::AutoCrdt;
use garage_util::error::*;
use serde::{Deserialize, Serialize};
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
#[serde(transparent)]
pub struct ReplicationFactor(usize);
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Default, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum ConsistencyMode {
/// Read- and Write-quorum are 1
Dangerous,
/// Read-quorum is 1
Degraded,
/// Read- and Write-quorum are determined for read-after-write-consistency
#[default]
Consistent,
}
impl ConsistencyMode {
pub fn parse(s: &str) -> Option<Self> {
serde_json::from_value(serde_json::Value::String(s.to_string())).ok()
}
}
impl AutoCrdt for ConsistencyMode {
const WARN_IF_DIFFERENT: bool = true;
}
impl ReplicationFactor {
pub fn new(replication_factor: usize) -> Option<Self> {
if replication_factor < 1 {
None
} else {
Some(Self(replication_factor))
}
}
pub fn replication_factor(&self) -> usize {
self.0
}
pub fn read_quorum(&self, consistency_mode: ConsistencyMode) -> usize {
match consistency_mode {
ConsistencyMode::Dangerous | ConsistencyMode::Degraded => 1,
ConsistencyMode::Consistent => self.replication_factor().div_ceil(2),
}
}
pub fn write_quorum(&self, consistency_mode: ConsistencyMode) -> usize {
match consistency_mode {
ConsistencyMode::Dangerous => 1,
ConsistencyMode::Degraded | ConsistencyMode::Consistent => {
(self.replication_factor() + 1) - self.read_quorum(ConsistencyMode::Consistent)
}
}
}
}
impl std::convert::From<ReplicationFactor> for usize {
fn from(replication_factor: ReplicationFactor) -> usize {
replication_factor.0
}
}
pub fn parse_replication_mode(
config: &Config,
) -> Result<(ReplicationFactor, ConsistencyMode), Error> {
match (&config.replication_mode, config.replication_factor, config.consistency_mode.as_str()) {
(Some(replication_mode), None, "consistent") => {
tracing::warn!("Legacy config option replication_mode in use. Please migrate to replication_factor and consistency_mode");
let parsed_replication_mode = match replication_mode.as_str() {
"1" | "none" => Some((ReplicationFactor(1), ConsistencyMode::Consistent)),
"2" => Some((ReplicationFactor(2), ConsistencyMode::Consistent)),
"2-dangerous" => Some((ReplicationFactor(2), ConsistencyMode::Dangerous)),
"3" => Some((ReplicationFactor(3), ConsistencyMode::Consistent)),
"3-degraded" => Some((ReplicationFactor(3), ConsistencyMode::Degraded)),
"3-dangerous" => Some((ReplicationFactor(3), ConsistencyMode::Dangerous)),
_ => None,
};
Some(parsed_replication_mode.ok_or_message("Invalid replication_mode in config file.")?)
},
(None, Some(replication_factor), consistency_mode) => {
let replication_factor = ReplicationFactor::new(replication_factor)
.ok_or_message("Invalid replication_factor in config file.")?;
let consistency_mode = ConsistencyMode::parse(consistency_mode)
.ok_or_message("Invalid consistency_mode in config file.")?;
Some((replication_factor, consistency_mode))
}
_ => None,
}.ok_or_message("Either the legacy replication_mode or replication_level and consistency_mode can be set, not both.")
}
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