scmstore: collect API usage metrics

Summary:
Instrument all the fetching-related legacy API implementations (ie, not `get_logged_fetches` and `get_shared_mutable`) to track the number of calls, keys, and single-key calls.

This introduces an additional lock acquisition to each of these implementations (and it'd be awkward to merge it with the one in `fetch`), but I think that's probably fine.

For APIs which do not support a variable number of keys, I use `.call(0)` so we simply track the total number of API calls.

Reviewed By: DurhamG

Differential Revision: D30003444

fbshipit-source-id: 8756d2669ca038b3f6a08e211e44e8ccb9251312

eden/scm/lib/revisionstore/src/scmstore/file/metrics.rs

@@ -70,6 +70,11 @@ impl FetchMetrics {
     }
 }
 
+// TODO(meyer): I don't think this is in any critical paths, but it'd be nicer to rewrite this
+// to use `Item = (Vec<&'static str>, usize)` instead of `Item = (String, usize)`, since all
+// the fields are indeed statically named right now, or, better, just tree of some sort instead of a
+// list of metrics. Probably appropriate for a `SmallVec` too, since the namespace depth is
+// limited.
 fn namespaced(
     namespace: &'static str,
     metrics: impl Iterator<Item = (impl AsRef<str>, usize)>,
@@ -240,10 +245,111 @@ impl FileStoreWriteMetrics {
     }
 }
 
+#[derive(Clone, Debug, Default)]
+pub struct ApiMetrics {
+    /// Number of calls to this API
+    calls: usize,
+
+    /// Total number of entities requested across all calls
+    keys: usize,
+
+    /// Number of calls for only a single entity
+    singles: usize,
+}
+
+impl AddAssign for ApiMetrics {
+    fn add_assign(&mut self, rhs: Self) {
+        self.calls += rhs.calls;
+        self.keys += rhs.keys;
+        self.singles += rhs.singles;
+    }
+}
+
+impl ApiMetrics {
+    pub(crate) fn call(&mut self, keys: usize) {
+        self.calls += 1;
+        self.keys += keys;
+        if keys == 1 {
+            self.singles += 1;
+        }
+    }
+
+    fn metrics(&self) -> impl Iterator<Item = (&'static str, usize)> {
+        std::array::IntoIter::new([
+            ("calls", self.calls),
+            ("keys", self.keys),
+            ("singles", self.singles),
+        ])
+        .filter(|&(_, v)| v != 0)
+    }
+}
+
+#[derive(Clone, Debug, Default)]
+pub struct FileStoreApiMetrics {
+    pub(crate) hg_getfilecontent: ApiMetrics,
+    pub(crate) hg_addpending: ApiMetrics,
+    pub(crate) hg_commitpending: ApiMetrics,
+    pub(crate) hg_get: ApiMetrics,
+    pub(crate) hg_getmeta: ApiMetrics,
+    pub(crate) hg_refresh: ApiMetrics,
+    pub(crate) hg_prefetch: ApiMetrics,
+    pub(crate) hg_upload: ApiMetrics,
+    pub(crate) hg_getmissing: ApiMetrics,
+    pub(crate) hg_add: ApiMetrics,
+    pub(crate) hg_flush: ApiMetrics,
+    pub(crate) contentdatastore_blob: ApiMetrics,
+    pub(crate) contentdatastore_metadata: ApiMetrics,
+}
+
+impl AddAssign for FileStoreApiMetrics {
+    fn add_assign(&mut self, rhs: Self) {
+        self.hg_getfilecontent += rhs.hg_getfilecontent;
+        self.hg_addpending += rhs.hg_addpending;
+        self.hg_commitpending += rhs.hg_commitpending;
+        self.hg_get += rhs.hg_get;
+        self.hg_getmeta += rhs.hg_getmeta;
+        self.hg_refresh += rhs.hg_refresh;
+        self.hg_prefetch += rhs.hg_prefetch;
+        self.hg_upload += rhs.hg_upload;
+        self.hg_getmissing += rhs.hg_getmissing;
+        self.hg_add += rhs.hg_add;
+        self.hg_flush += rhs.hg_flush;
+        self.contentdatastore_blob += rhs.contentdatastore_blob;
+        self.contentdatastore_metadata += rhs.contentdatastore_metadata;
+    }
+}
+
+impl FileStoreApiMetrics {
+    fn metrics(&self) -> impl Iterator<Item = (String, usize)> {
+        namespaced("hg_getfilecontent", self.hg_getfilecontent.metrics())
+            .chain(namespaced("hg_addpending", self.hg_addpending.metrics()))
+            .chain(namespaced(
+                "hg_commitpending",
+                self.hg_commitpending.metrics(),
+            ))
+            .chain(namespaced("hg_get", self.hg_get.metrics()))
+            .chain(namespaced("hg_getmeta", self.hg_getmeta.metrics()))
+            .chain(namespaced("hg_refresh", self.hg_refresh.metrics()))
+            .chain(namespaced("hg_prefetch", self.hg_prefetch.metrics()))
+            .chain(namespaced("hg_upload", self.hg_upload.metrics()))
+            .chain(namespaced("hg_getmissing", self.hg_getmissing.metrics()))
+            .chain(namespaced("hg_add", self.hg_add.metrics()))
+            .chain(namespaced(
+                "contentdatastore_blob",
+                self.contentdatastore_blob.metrics(),
+            ))
+            .chain(namespaced(
+                "contentdatastore_metadata",
+                self.contentdatastore_metadata.metrics(),
+            ))
+    }
+}
+
 #[derive(Debug, Default, Clone)]
 pub struct FileStoreMetrics {
     pub(crate) fetch: FileStoreFetchMetrics,
     pub(crate) write: FileStoreWriteMetrics,
+    pub(crate) api: FileStoreApiMetrics,
 }
 
 impl FileStoreMetrics {
@@ -255,7 +361,8 @@ impl FileStoreMetrics {
         namespaced(
             "scmstore.file",
             namespaced("fetch", self.fetch.metrics())
-                .chain(namespaced("write", self.write.metrics())),
+                .chain(namespaced("write", self.write.metrics()))
+                .chain(namespaced("api", self.api.metrics())),
         )
     }
 }

eden/scm/lib/revisionstore/src/scmstore/file/mod.rs

@@ -456,6 +456,7 @@ impl LegacyStore for FileStore {
 
     #[instrument(skip(self))]
     fn get_file_content(&self, key: &Key) -> Result<Option<Bytes>> {
+        self.metrics.write().api.hg_getfilecontent.call(0);
         self.fetch(std::iter::once(key.clone()), FileAttributes::CONTENT)
             .single()?
             .map(|entry| entry.content.unwrap().file_content())
@@ -471,6 +472,7 @@ impl LegacyStore for FileStore {
         meta: Metadata,
         location: RepackLocation,
     ) -> Result<()> {
+        self.metrics.write().api.hg_addpending.call(0);
         if let Some(contentstore) = self.contentstore.as_ref() {
             contentstore.add_pending(key, data, meta, location)
         } else {
@@ -488,6 +490,7 @@ impl LegacyStore for FileStore {
     }
 
     fn commit_pending(&self, location: RepackLocation) -> Result<Option<Vec<PathBuf>>> {
+        self.metrics.write().api.hg_commitpending.call(0);
         if let Some(contentstore) = self.contentstore.as_ref() {
             contentstore.commit_pending(location)
         } else {
@@ -500,6 +503,7 @@ impl LegacyStore for FileStore {
 impl HgIdDataStore for FileStore {
     // Fetch the raw content of a single TreeManifest blob
     fn get(&self, key: StoreKey) -> Result<StoreResult<Vec<u8>>> {
+        self.metrics.write().api.hg_get.call(0);
         Ok(
             match self
                 .fetch(
@@ -515,6 +519,7 @@ impl HgIdDataStore for FileStore {
     }
 
     fn get_meta(&self, key: StoreKey) -> Result<StoreResult<Metadata>> {
+        self.metrics.write().api.hg_getmeta.call(0);
         Ok(
             match self
                 .fetch(
@@ -530,6 +535,7 @@ impl HgIdDataStore for FileStore {
     }
 
     fn refresh(&self) -> Result<()> {
+        self.metrics.write().api.hg_refresh.call(0);
         // AFAIK refresh only matters for DataPack / PackStore
         Ok(())
     }
@@ -537,6 +543,7 @@ impl HgIdDataStore for FileStore {
 
 impl RemoteDataStore for FileStore {
     fn prefetch(&self, keys: &[StoreKey]) -> Result<Vec<StoreKey>> {
+        self.metrics.write().api.hg_prefetch.call(keys.len());
         Ok(self
             .fetch(
                 keys.iter().cloned().filter_map(|sk| sk.maybe_into_key()),
@@ -549,6 +556,7 @@ impl RemoteDataStore for FileStore {
     }
 
     fn upload(&self, keys: &[StoreKey]) -> Result<Vec<StoreKey>> {
+        self.metrics.write().api.hg_upload.call(keys.len());
         // TODO(meyer): Eliminate usage of legacy API, or at least minimize it (do we really need memcache + multiplex, etc)
         if let Some(ref lfs_remote) = self.lfs_remote {
             let mut multiplex = MultiplexDeltaStore::new();
@@ -570,6 +578,7 @@ impl RemoteDataStore for FileStore {
 
 impl LocalStore for FileStore {
     fn get_missing(&self, keys: &[StoreKey]) -> Result<Vec<StoreKey>> {
+        self.metrics.write().api.hg_getmissing.call(keys.len());
         Ok(self
             .local()
             .fetch(
@@ -585,6 +594,7 @@ impl LocalStore for FileStore {
 
 impl HgIdMutableDeltaStore for FileStore {
     fn add(&self, delta: &Delta, metadata: &Metadata) -> Result<()> {
+        self.metrics.write().api.hg_add.call(0);
         if let Delta {
             data,
             base: None,
@@ -598,6 +608,7 @@ impl HgIdMutableDeltaStore for FileStore {
     }
 
     fn flush(&self) -> Result<Option<Vec<PathBuf>>> {
+        self.metrics.write().api.hg_flush.call(0);
         self.flush()?;
         Ok(None)
     }
@@ -607,6 +618,7 @@ impl HgIdMutableDeltaStore for FileStore {
 // that if available, but I feel like there's probably something wrong if this is called for trees.
 impl ContentDataStore for FileStore {
     fn blob(&self, key: StoreKey) -> Result<StoreResult<Bytes>> {
+        self.metrics.write().api.contentdatastore_blob.call(0);
         Ok(
             match self
                 .fetch(
@@ -622,6 +634,7 @@ impl ContentDataStore for FileStore {
     }
 
     fn metadata(&self, key: StoreKey) -> Result<StoreResult<ContentMetadata>> {
+        self.metrics.write().api.contentdatastore_metadata.call(0);
         Ok(
             match self
                 .fetch(

eden/scm/tests/test-fb-hgext-treemanifest-pullpublic.t

@@ -24,7 +24,13 @@ Clone it
   fetching tree '' a539ce0c1a22b0ecf34498f9f5ce8ea56df9ecb7
   1 trees fetched over * (glob)
   2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over * (glob) (?)
-  { metrics : { scmstore : { file : { fetch : { contentstore : { hits : 2,
+  { metrics : { scmstore : { file : { api : { hg : { getfilecontent : { calls : 2},
+                                                     getmeta : { calls : 2},
+                                                     getmissing : { calls : 1,
+                                                                    keys : 2},
+                                                     prefetch : { calls : 3,
+                                                                  keys : 4}}},
+                                      fetch : { contentstore : { hits : 2,
                                                                  keys : 2,
                                                                  requests : 1},
                                                 indexedlog : { cache : { hits : 8,
@@ -86,7 +92,8 @@ Pull exactly up to d into the client
   adding manifests
   adding file changes
   added 2 changesets with 0 changes to 0 files
-  { metrics : { ssh : { connections : 1,
+  { metrics : { scmstore : { file : { api : { hg : { prefetch : { calls : 1}}}}},
+                ssh : { connections : 1,
                         read : { bytes : 1086},
                         write : { bytes : 680}}}}