make segmented changelog manager a facet

Summary:
The repo factory is the place where we have all elements needed for
instantiating a segmented changelog manager. Let's add that as an option.

It's going to be useful for some specialized binaries that don't just want to
query the segmented changelog but want to understand what version of SC do we
currently store an to be able to reload SC at will.

Reviewed By: quark-zju

Differential Revision: D35744722

fbshipit-source-id: 37f9dc4b5750b48212be1bffbdae189341fb2a06

eden/mononoke/repo_factory/src/lib.rs

@@ -76,7 +76,10 @@ use repo_identity::{ArcRepoIdentity, RepoIdentity};
 use repo_permission_checker::{ArcRepoPermissionChecker, ProdRepoPermissionChecker};
 use requests_table::{ArcLongRunningRequestsQueue, SqlLongRunningRequestsQueue};
 use scuba_ext::MononokeScubaSampleBuilder;
-use segmented_changelog::{new_server_segmented_changelog, SegmentedChangelogSqlConnections};
+use segmented_changelog::{
+    new_server_segmented_changelog, new_server_segmented_changelog_manager,
+    ArcSegmentedChangelogManager, SegmentedChangelogSqlConnections,
+};
 use segmented_changelog_types::ArcSegmentedChangelog;
 use skiplist::{ArcSkiplistIndex, SkiplistIndex};
 use slog::o;
@@ -493,6 +496,9 @@ pub enum RepoFactoryError {
     #[error("Error opening segmented changelog")]
     SegmentedChangelog,
 
+    #[error("Error starting segmented changelog manager")]
+    SegmentedChangelogManager,
+
     #[error("Missing cache pool: {0}")]
     MissingCachePool(String),
 
@@ -803,6 +809,35 @@ impl RepoFactory {
         Ok(Arc::new(segmented_changelog))
     }
 
+    pub async fn segmented_changelog_manager(
+        &self,
+        repo_config: &ArcRepoConfig,
+        repo_identity: &ArcRepoIdentity,
+        changeset_fetcher: &ArcChangesetFetcher,
+        bookmarks: &ArcBookmarks,
+        repo_blobstore: &ArcRepoBlobstore,
+    ) -> Result<ArcSegmentedChangelogManager> {
+        let sql_connections = self
+            .open::<SegmentedChangelogSqlConnections>(&repo_config.storage_config.metadata)
+            .await
+            .context(RepoFactoryError::SegmentedChangelog)?;
+        let pool = self.maybe_volatile_pool("segmented_changelog")?;
+        let manager = new_server_segmented_changelog_manager(
+            self.env.fb,
+            &self.ctx(Some(repo_identity)),
+            repo_identity,
+            repo_config.segmented_changelog_config.clone(),
+            sql_connections,
+            changeset_fetcher.clone(),
+            bookmarks.clone(),
+            repo_blobstore.clone(),
+            pool,
+        )
+        .await
+        .context(RepoFactoryError::SegmentedChangelogManager)?;
+        Ok(Arc::new(manager))
+    }
+
     pub fn repo_derived_data(
         &self,
         repo_identity: &ArcRepoIdentity,

eden/mononoke/segmented_changelog/Cargo.toml

@@ -26,6 +26,7 @@ changeset_fetcher = { version = "0.1.0", path = "../blobrepo/changeset_fetcher"
 changesets = { version = "0.1.0", path = "../changesets" }
 cloned = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 context = { version = "0.1.0", path = "../server/context" }
+facet = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 fbinit = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 futures = { version = "0.3.13", features = ["async-await", "compat"] }
 futures_ext = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }

eden/mononoke/segmented_changelog/src/lib.rs

@@ -47,10 +47,12 @@ pub use segmented_changelog_types::{
 };
 
 pub use crate::builder::{
-    new_server_segmented_changelog, new_test_segmented_changelog, SegmentedChangelogSqlConnections,
+    new_server_segmented_changelog, new_server_segmented_changelog_manager,
+    new_test_segmented_changelog, SegmentedChangelogSqlConnections,
 };
 pub use crate::clone_hints::CloneHints;
 pub use crate::copy::copy_segmented_changelog;
+pub use crate::manager::{ArcSegmentedChangelogManager, SegmentedChangelogManager};
 pub use crate::tailer::SegmentedChangelogTailer;
 pub use crate::update::{seedheads_from_config, SeedHead};
 

eden/mononoke/segmented_changelog/src/manager.rs

@@ -37,6 +37,7 @@ pub enum SegmentedChangelogType {
     Owned,
 }
 
+#[facet::facet]
 pub struct SegmentedChangelogManager {
     repo_id: RepositoryId,
     sc_version_store: SegmentedChangelogVersionStore,