Add WAL offloading to s3 on safekeepers.

Separate task is launched for each timeline and stopped when timeline doesn't
need offloading. Decision who offloads is done through etcd leader election;
currently there is no pre condition for participating, that's a TODO.

neon_local and tests infrastructure for remote storage in safekeepers added,
along with the test itself.

ref #1009

Co-authored-by: Anton Shyrabokau <ahtoxa@Antons-MacBook-Pro.local>

libs/etcd_broker/src/lib.rs

@@ -43,10 +43,10 @@ pub struct SkTimelineInfo {
     #[serde_as(as = "Option<DisplayFromStr>")]
     #[serde(default)]
     pub commit_lsn: Option<Lsn>,
-    /// LSN up to which safekeeper offloaded WAL to s3.
+    /// LSN up to which safekeeper has backed WAL.
     #[serde_as(as = "Option<DisplayFromStr>")]
     #[serde(default)]
-    pub s3_wal_lsn: Option<Lsn>,
+    pub backup_lsn: Option<Lsn>,
     /// LSN of last checkpoint uploaded by pageserver.
     #[serde_as(as = "Option<DisplayFromStr>")]
     #[serde(default)]

libs/remote_storage/Cargo.toml

@@ -6,7 +6,6 @@ edition = "2021"
 [dependencies]
 anyhow = { version = "1.0", features = ["backtrace"] }
 async-trait = "0.1"
-
 metrics = { version = "0.1", path = "../metrics" }
 once_cell = "1.8.0"
 rusoto_core = "0.48"
@@ -15,6 +14,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1"
 tokio = { version = "1.17", features = ["sync", "macros", "fs", "io-util"] }
 tokio-util = { version = "0.7", features = ["io"] }
+toml_edit = { version = "0.13", features = ["easy"] }
 tracing = "0.1.27"
 
 workspace_hack = { version = "0.1", path = "../../workspace_hack" }

libs/remote_storage/src/lib.rs

@@ -16,8 +16,10 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use anyhow::Context;
+use anyhow::{bail, Context};
+
 use tokio::io;
+use toml_edit::Item;
 use tracing::info;
 
 pub use self::{
@@ -203,6 +205,90 @@ pub fn path_with_suffix_extension(original_path: impl AsRef<Path>, suffix: &str)
         .with_extension(new_extension.as_ref())
 }
 
+impl RemoteStorageConfig {
+    pub fn from_toml(toml: &toml_edit::Item) -> anyhow::Result<RemoteStorageConfig> {
+        let local_path = toml.get("local_path");
+        let bucket_name = toml.get("bucket_name");
+        let bucket_region = toml.get("bucket_region");
+
+        let max_concurrent_syncs = NonZeroUsize::new(
+            parse_optional_integer("max_concurrent_syncs", toml)?
+                .unwrap_or(DEFAULT_REMOTE_STORAGE_MAX_CONCURRENT_SYNCS),
+        )
+        .context("Failed to parse 'max_concurrent_syncs' as a positive integer")?;
+
+        let max_sync_errors = NonZeroU32::new(
+            parse_optional_integer("max_sync_errors", toml)?
+                .unwrap_or(DEFAULT_REMOTE_STORAGE_MAX_SYNC_ERRORS),
+        )
+        .context("Failed to parse 'max_sync_errors' as a positive integer")?;
+
+        let concurrency_limit = NonZeroUsize::new(
+            parse_optional_integer("concurrency_limit", toml)?
+                .unwrap_or(DEFAULT_REMOTE_STORAGE_S3_CONCURRENCY_LIMIT),
+        )
+        .context("Failed to parse 'concurrency_limit' as a positive integer")?;
+
+        let storage = match (local_path, bucket_name, bucket_region) {
+            (None, None, None) => bail!("no 'local_path' nor 'bucket_name' option"),
+            (_, Some(_), None) => {
+                bail!("'bucket_region' option is mandatory if 'bucket_name' is given ")
+            }
+            (_, None, Some(_)) => {
+                bail!("'bucket_name' option is mandatory if 'bucket_region' is given ")
+            }
+            (None, Some(bucket_name), Some(bucket_region)) => RemoteStorageKind::AwsS3(S3Config {
+                bucket_name: parse_toml_string("bucket_name", bucket_name)?,
+                bucket_region: parse_toml_string("bucket_region", bucket_region)?,
+                prefix_in_bucket: toml
+                    .get("prefix_in_bucket")
+                    .map(|prefix_in_bucket| parse_toml_string("prefix_in_bucket", prefix_in_bucket))
+                    .transpose()?,
+                endpoint: toml
+                    .get("endpoint")
+                    .map(|endpoint| parse_toml_string("endpoint", endpoint))
+                    .transpose()?,
+                concurrency_limit,
+            }),
+            (Some(local_path), None, None) => RemoteStorageKind::LocalFs(PathBuf::from(
+                parse_toml_string("local_path", local_path)?,
+            )),
+            (Some(_), Some(_), _) => bail!("local_path and bucket_name are mutually exclusive"),
+        };
+
+        Ok(RemoteStorageConfig {
+            max_concurrent_syncs,
+            max_sync_errors,
+            storage,
+        })
+    }
+}
+
+// Helper functions to parse a toml Item
+fn parse_optional_integer<I, E>(name: &str, item: &toml_edit::Item) -> anyhow::Result<Option<I>>
+where
+    I: TryFrom<i64, Error = E>,
+    E: std::error::Error + Send + Sync + 'static,
+{
+    let toml_integer = match item.get(name) {
+        Some(item) => item
+            .as_integer()
+            .with_context(|| format!("configure option {name} is not an integer"))?,
+        None => return Ok(None),
+    };
+
+    I::try_from(toml_integer)
+        .map(Some)
+        .with_context(|| format!("configure option {name} is too large"))
+}
+
+fn parse_toml_string(name: &str, item: &Item) -> anyhow::Result<String> {
+    let s = item
+        .as_str()
+        .with_context(|| format!("configure option {name} is not a string"))?;
+    Ok(s.to_string())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

libs/utils/src/lsn.rs

@@ -26,6 +26,9 @@ impl Lsn {
     /// Maximum possible value for an LSN
     pub const MAX: Lsn = Lsn(u64::MAX);
 
+    /// Invalid value for InvalidXLogRecPtr, as defined in xlogdefs.h
+    pub const INVALID: Lsn = Lsn(0);
+
     /// Subtract a number, returning None on overflow.
     pub fn checked_sub<T: Into<u64>>(self, other: T) -> Option<Lsn> {
         let other: u64 = other.into();
@@ -103,6 +106,12 @@ impl Lsn {
     pub fn is_aligned(&self) -> bool {
         *self == self.align()
     }
+
+    /// Return if the LSN is valid
+    /// mimics postgres XLogRecPtrIsInvalid macro
+    pub fn is_valid(self) -> bool {
+        self != Lsn::INVALID
+    }
 }
 
 impl From<u64> for Lsn {