Add safekeeper membership conf to control file.

libs/safekeeper_api/Cargo.toml

@@ -5,8 +5,10 @@ edition.workspace = true
 license.workspace = true
 
 [dependencies]
+anyhow.workspace = true
 const_format.workspace = true
 serde.workspace = true
+serde_json.workspace = true
 postgres_ffi.workspace = true
 pq_proto.workspace = true
 tokio.workspace = true

libs/safekeeper_api/src/lib.rs

@@ -4,6 +4,7 @@ use const_format::formatcp;
 use pq_proto::SystemId;
 use serde::{Deserialize, Serialize};
 
+pub mod membership;
 /// Public API types
 pub mod models;
 

libs/safekeeper_api/src/membership.rs

@@ -0,0 +1,163 @@
+//! Types defining safekeeper membership, see
+//! rfcs/035-safekeeper-dynamic-membership-change.md
+//! for details.
+
+use std::{collections::HashSet, fmt::Display};
+
+use anyhow;
+use anyhow::bail;
+use serde::{Deserialize, Serialize};
+use utils::id::NodeId;
+
+/// Number uniquely identifying safekeeper configuration.
+/// Note: it is a part of sk control file.
+pub type Generation = u32;
+/// 1 is the first valid generation, 0 is used as
+/// a placeholder before we fully migrate to generations.
+pub const INVALID_GENERATION: Generation = 0;
+
+/// Membership is defined by ids so e.g. walproposer uses them to figure out
+/// quorums, but we also carry host and port to give wp idea where to connect.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct SafekeeperId {
+    pub id: NodeId,
+    pub host: String,
+    pub pg_port: u16,
+}
+
+impl Display for SafekeeperId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "[id={}, ep={}:{}]", self.id, self.host, self.pg_port)
+    }
+}
+
+/// Set of safekeepers.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(transparent)]
+pub struct MemberSet {
+    pub members: Vec<SafekeeperId>,
+}
+
+impl MemberSet {
+    pub fn empty() -> Self {
+        MemberSet {
+            members: Vec::new(),
+        }
+    }
+
+    pub fn new(members: Vec<SafekeeperId>) -> anyhow::Result<Self> {
+        let hs: HashSet<NodeId> = HashSet::from_iter(members.iter().map(|sk| sk.id));
+        if hs.len() != members.len() {
+            bail!("duplicate safekeeper id in the set {:?}", members);
+        }
+        Ok(MemberSet { members })
+    }
+
+    pub fn contains(&self, sk: &SafekeeperId) -> bool {
+        self.members.iter().any(|m| m.id == sk.id)
+    }
+
+    pub fn add(&mut self, sk: SafekeeperId) -> anyhow::Result<()> {
+        if self.contains(&sk) {
+            bail!(format!(
+                "sk {} is already member of the set {}",
+                sk.id, self
+            ));
+        }
+        self.members.push(sk);
+        Ok(())
+    }
+}
+
+impl Display for MemberSet {
+    /// Display as a comma separated list of members.
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let sks_str = self
+            .members
+            .iter()
+            .map(|m| m.to_string())
+            .collect::<Vec<_>>();
+        write!(f, "({})", sks_str.join(", "))
+    }
+}
+
+/// Safekeeper membership configuration.
+/// Note: it is a part of both control file and http API.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct Configuration {
+    /// Unique id.
+    pub generation: Generation,
+    /// Current members of the configuration.
+    pub members: MemberSet,
+    /// Some means it is a joint conf.
+    pub new_members: Option<MemberSet>,
+}
+
+impl Configuration {
+    /// Used for pre-generations timelines, will be removed eventually.
+    pub fn empty() -> Self {
+        Configuration {
+            generation: INVALID_GENERATION,
+            members: MemberSet::empty(),
+            new_members: None,
+        }
+    }
+}
+
+impl Display for Configuration {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "gen={}, members={}, new_members={}",
+            self.generation,
+            self.members,
+            self.new_members
+                .as_ref()
+                .map(ToString::to_string)
+                .unwrap_or(String::from("none"))
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{MemberSet, SafekeeperId};
+    use utils::id::NodeId;
+
+    #[test]
+    fn test_member_set() {
+        let mut members = MemberSet::empty();
+        members
+            .add(SafekeeperId {
+                id: NodeId(42),
+                host: String::from("lala.org"),
+                pg_port: 5432,
+            })
+            .unwrap();
+
+        members
+            .add(SafekeeperId {
+                id: NodeId(42),
+                host: String::from("lala.org"),
+                pg_port: 5432,
+            })
+            .expect_err("duplicate must not be allowed");
+
+        members
+            .add(SafekeeperId {
+                id: NodeId(43),
+                host: String::from("bubu.org"),
+                pg_port: 5432,
+            })
+            .unwrap();
+
+        println!("members: {}", members);
+
+        let j = serde_json::to_string(&members).expect("failed to serialize");
+        println!("members json: {}", j);
+        assert_eq!(
+            j,
+            r#"[{"id":42,"host":"lala.org","pg_port":5432},{"id":43,"host":"bubu.org","pg_port":5432}]"#
+        );
+    }
+}

libs/safekeeper_api/src/models.rs

@@ -11,7 +11,7 @@ use utils::{
     pageserver_feedback::PageserverFeedback,
 };
 
-use crate::{ServerInfo, Term};
+use crate::{membership::Configuration, ServerInfo, Term};
 
 #[derive(Debug, Serialize)]
 pub struct SafekeeperStatus {
@@ -22,7 +22,7 @@ pub struct SafekeeperStatus {
 pub struct TimelineCreateRequest {
     pub tenant_id: TenantId,
     pub timeline_id: TimelineId,
-    pub peer_ids: Option<Vec<NodeId>>,
+    pub mconf: Configuration,
     pub pg_version: u32,
     pub system_id: Option<u64>,
     pub wal_seg_size: Option<u32>,

safekeeper/src/control_file.rs

@@ -3,6 +3,7 @@
 use anyhow::{bail, ensure, Context, Result};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use camino::{Utf8Path, Utf8PathBuf};
+use safekeeper_api::membership::INVALID_GENERATION;
 use tokio::fs::File;
 use tokio::io::AsyncWriteExt;
 use utils::crashsafe::durable_rename;
@@ -13,14 +14,14 @@ use std::ops::Deref;
 use std::path::Path;
 use std::time::Instant;
 
-use crate::control_file_upgrade::downgrade_v9_to_v8;
+use crate::control_file_upgrade::downgrade_v10_to_v9;
 use crate::control_file_upgrade::upgrade_control_file;
 use crate::metrics::PERSIST_CONTROL_FILE_SECONDS;
 use crate::state::{EvictionState, TimelinePersistentState};
 use utils::bin_ser::LeSer;
 
 pub const SK_MAGIC: u32 = 0xcafeceefu32;
-pub const SK_FORMAT_VERSION: u32 = 9;
+pub const SK_FORMAT_VERSION: u32 = 10;
 
 // contains persistent metadata for safekeeper
 pub const CONTROL_FILE_NAME: &str = "safekeeper.control";
@@ -169,10 +170,11 @@ impl TimelinePersistentState {
         let mut buf: Vec<u8> = Vec::new();
         WriteBytesExt::write_u32::<LittleEndian>(&mut buf, SK_MAGIC)?;
 
-        if self.eviction_state == EvictionState::Present {
-            // temp hack for forward compatibility
-            const PREV_FORMAT_VERSION: u32 = 8;
-            let prev = downgrade_v9_to_v8(self);
+        if self.mconf.generation == INVALID_GENERATION {
+            // Temp hack for forward compatibility test: in case of none
+            // configuration save cfile in previous v9 format.
+            const PREV_FORMAT_VERSION: u32 = 9;
+            let prev = downgrade_v10_to_v9(self);
             WriteBytesExt::write_u32::<LittleEndian>(&mut buf, PREV_FORMAT_VERSION)?;
             prev.ser_into(&mut buf)?;
         } else {
@@ -233,6 +235,7 @@ impl Storage for FileStorage {
 #[cfg(test)]
 mod test {
     use super::*;
+    use safekeeper_api::membership::{Configuration, MemberSet};
     use tokio::fs;
     use utils::lsn::Lsn;
 
@@ -242,6 +245,11 @@ mod test {
     async fn test_read_write_safekeeper_state() -> anyhow::Result<()> {
         let tempdir = camino_tempfile::tempdir()?;
         let mut state = TimelinePersistentState::empty();
+        state.mconf = Configuration {
+            generation: 42,
+            members: MemberSet::empty(),
+            new_members: None,
+        };
         let mut storage = FileStorage::create_new(tempdir.path(), state.clone(), NO_SYNC).await?;
 
         // Make a change.