[web] resync_projects: use the secondaries for all reads (#33684)

* [docstore] add useSecondary flag to projectHasRanges

The rev-check for unarchiving always consults with the primary.

Two extra changes:
- Add a projection argument to peekDoc in order to skip lines download
   from projectHasRanges.
- Add one retry to peekDoc to reduce chances of surfacing a rev-check
   violation.

* [web] resync_projects: use the secondaries for all reads

* [web] add default value for useSecondary

* [docstore] add default value for useSecondary

* [k8s] docstore: set MONGO_HAS_SECONDARIES=true

GitOrigin-RevId: f15ec4fdc1cabe74c1eab87bec85f28d6f7a587d

services/docstore/app/js/DocManager.js

@@ -77,15 +77,17 @@ const DocManager = {
   },
 
   // returns the doc without any version information
-  async _peekRawDoc(projectId, docId) {
-    const doc = await MongoManager.findDoc(projectId, docId, {
-      lines: true,
-      rev: true,
-      deleted: true,
-      version: true,
-      ranges: true,
-      inS3: true,
-    })
+  async _peekRawDoc(projectId, docId, projection, useSecondary) {
+    const doc = await MongoManager.findDoc(
+      projectId,
+      docId,
+      {
+        ...projection,
+        rev: true,
+        inS3: true,
+      },
+      useSecondary
+    )
 
     if (doc == null) {
       throw new Errors.NotFoundError(
@@ -97,6 +99,8 @@ const DocManager = {
       // skip the unarchiving to mongo when getting a doc
       const archivedDoc = await DocArchive.getDoc(projectId, docId)
       Object.assign(doc, archivedDoc)
+      // Always use the primary for the rev-check.
+      await MongoManager.checkRevUnchanged(doc)
     }
 
     return doc
@@ -104,10 +108,21 @@ const DocManager = {
 
   // get the doc from mongo if possible, or from the persistent store otherwise,
   // without unarchiving it (avoids unnecessary writes to mongo)
-  async peekDoc(projectId, docId) {
-    const doc = await DocManager._peekRawDoc(projectId, docId)
-    await MongoManager.checkRevUnchanged(doc)
-    return doc
+  async peekDoc(projectId, docId, projection, useSecondary = false) {
+    try {
+      return await DocManager._peekRawDoc(
+        projectId,
+        docId,
+        projection,
+        useSecondary
+      )
+    } catch (err) {
+      if (err instanceof Errors.DocModifiedError) {
+        // Try again once on rev mismatch. Always use the primary for retries.
+        return await DocManager._peekRawDoc(projectId, docId, projection, false)
+      }
+      throw err
+    }
   },
 
   async getDocLines(projectId, docId) {
@@ -181,11 +196,20 @@ const DocManager = {
     return Array.from(userIds)
   },
 
-  async projectHasRanges(projectId) {
-    const docs = await MongoManager.getProjectsDocs(projectId, {}, { _id: 1 })
+  async projectHasRanges(projectId, useSecondary) {
+    const docs = await MongoManager.getProjectsDocs(
+      projectId,
+      { useSecondary },
+      { _id: 1 }
+    )
     const docIds = docs.map(doc => doc._id)
     for (const docId of docIds) {
-      const doc = await DocManager.peekDoc(projectId, docId)
+      const doc = await DocManager.peekDoc(
+        projectId,
+        docId,
+        { ranges: true },
+        useSecondary
+      )
       if (
         (doc.ranges?.comments != null && doc.ranges.comments.length > 0) ||
         (doc.ranges?.changes != null && doc.ranges.changes.length > 0)