quorum: add joint group commit (#401)

Signed-off-by: accelsao <jayzhan211@gmail.com>

src/quorum/datadriven_test.rs

@@ -23,6 +23,9 @@ fn test_quorum(data: &TestData) -> String {
     // quorum test instead of a majority quorum test for cfg only).
     let mut idxs: Vec<Index> = Vec::new();
 
+    // group id of each nodes in the config.
+    let mut gids: Vec<u64> = Vec::new();
+
     // Votes. These are initialized similar to idxs except the only values
     // used are 1 (voted against) and 2 (voted for). This looks awkward,
     // but is convenient because it allows sharing code between the two.
@@ -58,6 +61,16 @@ fn test_quorum(data: &TestData) -> String {
                         group_id: 0,
                     });
                 }
+                "gid" => {
+                    let mut n: u64 = 0;
+                    if val != "_" {
+                        n = val.parse().expect("type of n should be u64");
+                        if n == 0 {
+                            panic!("use '_' as 0, check {}", data.pos)
+                        }
+                    }
+                    gids.push(n);
+                }
                 "votes" => match val.as_str() {
                     "y" => votes.push(Index {
                         index: 2,
@@ -127,6 +140,22 @@ fn test_quorum(data: &TestData) -> String {
         );
     }
 
+    // verify length of group ids
+    if !gids.is_empty() {
+        if gids.len() != voters {
+            return format!(
+                "error: mismatched input (explicit or _) for group ids {:?}: {:?}",
+                voters,
+                gids.len()
+            );
+        } else {
+            // assign group ids to idxs
+            for (idx, gid) in idxs.iter_mut().zip(gids) {
+                idx.group_id = gid;
+            }
+        }
+    }
+
     // buffer for expected value
     let mut buf = String::new();
 
@@ -223,6 +252,35 @@ fn test_quorum(data: &TestData) -> String {
                 }
             ));
         }
+        "group_committed" => {
+            let use_group_commit = true;
+
+            let l = make_lookuper(&idxs, &ids, &idsj);
+
+            let mut idx = (0, false);
+
+            if joint {
+                let cc = JointConfig::new_joint_from_majorities(c.clone(), cj.clone());
+                // `describe` doesn't seem to be useful for group commit.
+                // buf.push_str(&cc.describe(&l));
+                idx = cc.committed_index(use_group_commit, &l);
+                // Interchanging the majorities shouldn't make a difference. If it does, print.
+                let a_idx = JointConfig::new_joint_from_majorities(cj, c)
+                    .committed_index(use_group_commit, &l);
+                if a_idx != idx {
+                    buf.push_str(&format!("{} <-- via symmetry\n", a_idx.0));
+                }
+            } else {
+                // TODO: majority group commit
+            }
+            buf.push_str(&format!(
+                "{}\n",
+                Index {
+                    index: idx.0,
+                    group_id: 0
+                }
+            ));
+        }
         "vote" => {
             let ll = make_lookuper(&votes, &ids, &idsj);
             let mut l = HashMap::default();

src/quorum/testdata/joint_group_commit.txt

@@ -0,0 +1,76 @@
+# the same result of joint single group commit
+group_committed cfg=(1,2,3) cfgj=zero idx=(100,101,99) gid=(1,1,1)
+----
+100
+
+# min(quorum_commit_index = 100, first index that appears in second group = 99)
+group_committed cfg=(1,2,3) cfgj=zero idx=(100,101,99) gid=(1,1,2)
+----
+99
+
+# min(quorum_commit_index = 100, first index that appears in second group = 101)
+group_committed cfg=(1,2,3) cfgj=zero idx=(100,101,99) gid=(2,1,1)
+----
+100
+
+# minimum index = 99
+group_committed cfg=(1,2,3) cfgj=zero idx=(100,101,99) gid=(_,1,1)
+----
+99
+
+# min(quorum_commit_index = 100, first index that appears in second group = 99)
+group_committed cfg=(1,2,3) cfgj=zero idx=(100,101,99) gid=(_,1,2)
+----
+99
+
+# minimum index = 98
+group_committed cfg=(1,2,3,4,5) cfgj=zero idx=(100,101,99,102,98) gid=(_,_,_,_,1)
+----
+98
+
+# cfg 1 = min(quorum_commit_index = 100, first index that appears in second group = 99) 
+# cfg 2 = min(quorum_commit_index = 100, first index that appears in second group = 1) 
+group_committed cfg=(1,2,3,4) cfgj=(3,4,5,6) idx=(101,99,100,102,103,1) gid=(1,_,1,1,_,2)
+----
+1
+
+# cfg 1 = min(quorum_commit_index = 100, first index that appears in second group = 101)
+# cfg 2 = min(quorum_commit_index = 100, first index that appears in second group = 101)
+group_committed cfg=(1,2,3) cfgj=(4,5,6) idx=(99,100,101,99,100,101) gid=(1,1,2,1,2,1)
+----
+100
+
+# cfg 1 = min(quorum_commit_index = 100, first index that appears in second group = 101)
+# cfg 2 = minimum index = 99
+group_committed cfg=(1,2,3) cfgj=(4,5,6) idx=(99,100,101,99,100,101) gid=(1,1,2,1,1,_)
+----
+99
+
+# min(quorum_commit_index = 101, first index that appears in second group = 103)
+group_committed cfg=(1,2,3,4,5) cfgj=zero idx=(99,100,101,102,103) gid=(1,1,1,1,2)
+----
+101
+
+# cfg 1 = minimum index = 1
+# cfg 2 = minimum index = 2
+group_committed cfg=(1,2,3,4,5) cfgj=(2,3,4,5,6) idx=(1,100,101,102,103,2) gid=(1,_,1,1,1,1)
+----
+1
+
+# cfg 1 = minimum index = 3
+# cfg 2 = quorum_commit_index = 101
+group_committed cfg=(1,2,3,4,5) cfgj=(2,3,4,5,6) idx=(3,100,101,102,103,2) gid=(_,1,1,1,1,1)
+----
+3
+
+# cfg 1 = min(quorum_commit_index = 101, first index that appears in second group = 103)
+# cfg 2 = min(quorum_commit_index = 101, first index that appears in second group = 103)
+group_committed cfg=(1,2,3,4,5) cfgj=(2,3,4,5,6) idx=(3,100,101,102,103,2) gid=(_,1,1,1,3,1)
+----
+101
+
+# cfg 1 = minimum index = 3
+# cfg 2 = min(quorum_commit_index = 101, first index that appears in second group = 2)
+group_committed cfg=(1,2,3,4,5) cfgj=(2,3,4,5,6) idx=(3,100,101,102,103,2) gid=(_,1,1,1,1,3)
+----
+2