CBG-4776: Fetch by CV REST API

db/crud.go

@@ -295,13 +295,13 @@ func (c *DatabaseCollection) OnDemandImportForGet(ctx context.Context, docid str
 	return docOut, nil
 }
 
-// GetRev returns the revision for the given docID and revID, or the current active revision if revID is empty.
-func (db *DatabaseCollectionWithUser) GetRev(ctx context.Context, docID, revID string, history bool, attachmentsSince []string) (DocumentRevision, error) {
+// GetRev returns the revision for the given docID and revOrCV, or the current active revision if revOrCV is empty.
+func (db *DatabaseCollectionWithUser) GetRev(ctx context.Context, docID, revOrCV string, history bool, attachmentsSince []string) (DocumentRevision, error) {
 	maxHistory := 0
 	if history {
 		maxHistory = math.MaxInt32
 	}
-	return db.getRev(ctx, docID, revID, maxHistory, nil)
+	return db.getRev(ctx, docID, revOrCV, maxHistory, nil)
 }
 
 // Returns the body of the current revision of a document
@@ -2765,6 +2765,7 @@ func (db *DatabaseCollectionWithUser) postWriteUpdateHLV(ctx context.Context, do
 		doc.HLV.CurrentVersionCAS = casOut
 	}
 	// backup new revision to the bucket now we have a doc assigned a CV (post macro expansion) for delta generation purposes
+	// we don't need to store revision body backups without delta sync in 4.0, since all clients know how to use the sendReplacementRevs feature
 	backupRev := db.deltaSyncEnabled() && db.deltaSyncRevMaxAgeSeconds() != 0
 	if db.UseXattrs() && backupRev {
 		var newBodyWithAtts = doc._rawBody

docs/api/components/parameters.yaml

@@ -342,7 +342,7 @@ rev:
   schema:
     type: string
   example: 2-5145e1086bb8d1d71a531e9f6b543c58
-  description: The document revision to target. If this is a CV value, ensure the query parameter is URL encoded (`+`->`%2B`, `@`->`%40`, etc.)
+  description: The document revision to target. This can be a RevTree ID or a CV (Current Version) ID. If this is a CV value, ensure the query parameter is URL encoded (`+`->`%2B`, `@`->`%40`, etc.)
 revs_from:
   name: revs_from
   in: query

docs/api/paths/public/keyspace-docid.yaml

@@ -27,7 +27,7 @@ get:
         Etag:
           schema:
             type: string
-          description: The document revision ID if only returning 1 revision.
+          description: An optimistic concurrency control (OCC) value used to prevent conflicts in a subsequent update. This value can be a RevTree ID or a CV (Current Version) ID, depending on the version type requested.
       content:
         application/json:
           schema:

rest/attachment_test.go

@@ -2135,6 +2135,9 @@ func TestAttachmentsMissing(t *testing.T) {
 
 	rt.GetDatabase().FlushRevisionCacheForTest()
 
+	// strip CV from version - we don't store revision backups for old CVs like we do for RevIDs
+	version2.CV = db.Version{}
+
 	body := rt.GetDocVersion(docID, version2)
 	require.Equal(t, "sha1-Kq5sNclPz7QV2+lfQIuc6R7oRu0=", body["_attachments"].(map[string]interface{})["hello.txt"].(map[string]interface{})["digest"])
 }
@@ -2158,6 +2161,9 @@ func TestAttachmentsMissingNoBody(t *testing.T) {
 
 	rt.GetDatabase().FlushRevisionCacheForTest()
 
+	// strip CV from version - we don't store revision backups for old CVs like we do for RevIDs
+	version2.CV = db.Version{}
+
 	body := rt.GetDocVersion(docID, version2)
 	require.Equal(t, "sha1-Kq5sNclPz7QV2+lfQIuc6R7oRu0=", body["_attachments"].(map[string]interface{})["hello.txt"].(map[string]interface{})["digest"])
 }

rest/doc_api.go

@@ -27,15 +27,24 @@ import (
 // HTTP handler for a GET of a document
 func (h *handler) handleGetDoc() error {
 	docid := h.PathVar("docid")
-	revid := h.getQuery("rev")
+	rev := h.getQuery("rev") // Empty, RevTree ID, or CV
 	openRevs := h.getQuery("open_revs")
 	showExp := h.getBoolQuery("show_exp")
 	const showCV = true // Post-beta 4.0 _always_ returns CV - negligible impact to revtree-only clients and promotes CV as the preferred OCC value
 
 	if replicator2, _ := h.getOptBoolQuery("replicator2", false); replicator2 {
-		return h.handleGetDocReplicator2(docid, revid)
+		return h.handleGetDocReplicator2(docid, rev)
+	}
+
+	// Extra validation of these options, since this combination isn't valid anyway. We want to prevent users from attempting to use CV with open_revs.
+	if openRevs != "" && rev != "" {
+		return base.HTTPErrorf(http.StatusBadRequest, "cannot specify both 'rev' and 'open_revs' query parameters")
 	}
 
+	// We'll treat empty rev as a RevTree ID, which only affects what the ETag looks like.
+	// If the user specifically asked for a CV, they'll get a CV ETag - but everything else can stay as RevTree ID for compatibility.
+	isRevTreeID := rev == "" || base.IsRevTreeID(rev)
+
 	// Check whether the caller wants a revision history, or attachment bodies, or both:
 	var revsLimit = 0
 	var revsFrom, attachmentsSince []string
@@ -69,7 +78,7 @@ func (h *handler) handleGetDoc() error {
 
 	if openRevs == "" {
 		// Single-revision GET:
-		value, err := h.collection.Get1xRevBodyWithHistory(h.ctx(), docid, revid, db.Get1xRevBodyOptions{
+		value, err := h.collection.Get1xRevBodyWithHistory(h.ctx(), docid, rev, db.Get1xRevBodyOptions{
 			MaxHistory:       revsLimit,
 			HistoryFrom:      revsFrom,
 			AttachmentsSince: attachmentsSince,
@@ -94,8 +103,14 @@ func (h *handler) handleGetDoc() error {
 			}
 			return kNotFoundError
 		}
-		foundRev := value[db.BodyRev].(string)
-		h.setEtag(foundRev)
+
+		var etagValue string
+		if isRevTreeID {
+			etagValue = value[db.BodyRev].(string)
+		} else {
+			etagValue = value[db.BodyCV].(string)
+		}
+		h.setEtag(etagValue)
 
 		h.db.DbStats.Database().NumDocReadsRest.Add(1)
 		hasBodies := attachmentsSince != nil && value[db.BodyAttachments] != nil
@@ -110,7 +125,7 @@ func (h *handler) handleGetDoc() error {
 		}
 		base.Audit(h.ctx(), base.AuditIDDocumentRead, base.AuditFields{
 			base.AuditFieldDocID:      docid,
-			base.AuditFieldDocVersion: foundRev,
+			base.AuditFieldDocVersion: etagValue,
 		})
 	} else {
 		var revids []string
@@ -195,12 +210,12 @@ func (h *handler) handleGetDoc() error {
 	return nil
 }
 
-func (h *handler) handleGetDocReplicator2(docid, revid string) error {
+func (h *handler) handleGetDocReplicator2(docid, revOrCV string) error {
 	if !base.IsEnterpriseEdition() {
 		return base.HTTPErrorf(http.StatusNotImplemented, "replicator2 endpoints are only supported in EE")
 	}
 
-	rev, err := h.collection.GetRev(h.ctx(), docid, revid, true, nil)
+	rev, err := h.collection.GetRev(h.ctx(), docid, revOrCV, true, nil)
 	if err != nil {
 		return err
 	}

rest/utilities_testing_resttester.go

@@ -78,7 +78,20 @@ func (rt *RestTester) TriggerOnDemandImport(docID string) {
 
 // GetDocVersion returns the doc body and version for the given docID and version. If the document is not found, t.Fail will be called.
 func (rt *RestTester) GetDocVersion(docID string, version DocVersion) db.Body {
-	rawResponse := rt.SendAdminRequest("GET", "/{{.keyspace}}/"+docID+"?rev="+version.RevTreeID, "")
+	occValue := version.RevTreeID
+	if !version.CV.IsEmpty() {
+		occValue = version.CV.String()
+	}
+	rawResponse := rt.SendAdminRequest("GET", "/{{.keyspace}}/"+docID+"?rev="+url.QueryEscape(occValue), "")
+	RequireStatus(rt.TB(), rawResponse, http.StatusOK)
+	var body db.Body
+	require.NoError(rt.TB(), base.JSONUnmarshal(rawResponse.Body.Bytes(), &body))
+	return body
+}
+
+// GetDocByRev returns the doc body for the given docID and Rev. If the document is not found, t.Fail will be called.
+func (rt *RestTester) GetDocByRev(docID, revTreeID string) db.Body {
+	rawResponse := rt.SendAdminRequest("GET", fmt.Sprintf("/%s/%s?rev=%s", rt.GetSingleKeyspace(), docID, revTreeID), "")
 	RequireStatus(rt.TB(), rawResponse, http.StatusOK)
 	var body db.Body
 	require.NoError(rt.TB(), base.JSONUnmarshal(rawResponse.Body.Bytes(), &body))
@@ -143,11 +156,6 @@ func isRespUseRevTreeIDInstead(resp *TestResponse) bool {
 	return resp.Code == http.StatusBadRequest && strings.Contains(resp.BodyString(), "Cannot use CV to modify a document in conflict - resolve first with RevTree ID")
 }
 
-// DeleteDocRev removes a document at a specific revision. Deprecated for DeleteDoc.
-func (rt *RestTester) DeleteDocRev(docID, revID string) {
-	rt.DeleteDoc(docID, DocVersion{RevTreeID: revID})
-}
-
 func (rt *RestTester) GetDatabaseRoot(dbname string) DatabaseRoot {
 	var dbroot DatabaseRoot
 	resp := rt.SendAdminRequest("GET", "/"+dbname+"/", "")