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