Introduce lifecycle function calls for requests

These are intended to support instrumentation with bpftrace.

Signed-off-by: Cole Miller <cole.miller@canonical.com>

Author: cole-miller

Makefile.am

@@ -19,6 +19,7 @@ libraft_la_SOURCES = \
   src/entry.c \
   src/err.c \
   src/heap.c \
+  src/lifecycle.c \
   src/log.c \
   src/membership.c \
   src/progress.c \

include/raft.h

@@ -909,6 +909,7 @@ RAFT_API raft_index raft_last_applied(struct raft *r);
     void *data;       \
     int type;         \
     raft_index index; \
+    long id;          \
     void *queue[2]
 
 /**

src/client.c

@@ -1,7 +1,10 @@
+#include <stdlib.h>
+
 #include "../include/raft.h"
 #include "assert.h"
 #include "configuration.h"
 #include "err.h"
+#include "lifecycle.h"
 #include "log.h"
 #include "membership.h"
 #include "progress.h"
@@ -39,6 +42,7 @@ int raft_apply(struct raft *r,
     tracef("%u commands starting at %lld", n, index);
     req->type = RAFT_COMMAND;
     req->index = index;
+    req->id = random();
     req->cb = cb;
 
     /* Append the new entries to the log. */
@@ -47,7 +51,7 @@ int raft_apply(struct raft *r,
         goto err;
     }
 
-    QUEUE_PUSH(&r->leader_state.requests, &req->queue);
+    lifecycleRequestStart(r, (struct request *)req);
 
     rv = replicationTrigger(r, index);
     if (rv != 0) {
@@ -89,14 +93,15 @@ int raft_barrier(struct raft *r, struct raft_barrier *req, raft_barrier_cb cb)
     tracef("barrier starting at %lld", index);
     req->type = RAFT_BARRIER;
     req->index = index;
+    req->id = random();
     req->cb = cb;
 
     rv = logAppend(&r->log, r->current_term, RAFT_BARRIER, &buf, NULL);
     if (rv != 0) {
         goto err_after_buf_alloc;
     }
 
-    QUEUE_PUSH(&r->leader_state.requests, &req->queue);
+    lifecycleRequestStart(r, (struct request *)req);
 
     rv = replicationTrigger(r, index);
     if (rv != 0) {

src/lifecycle.c

@@ -0,0 +1,15 @@
+#include "lifecycle.h"
+#include "queue.h"
+
+#include <stdlib.h>
+
+void lifecycleRequestStart(struct raft *r, struct request *req)
+{
+    QUEUE_PUSH(&r->leader_state.requests, &req->queue);
+}
+
+void lifecycleRequestEnd(struct raft *r, struct request *req)
+{
+    (void)r;
+    QUEUE_REMOVE(&req->queue);
+}

src/lifecycle.h

@@ -0,0 +1,10 @@
+#ifndef LIFECYCLE_H_
+#define LIFECYCLE_H_
+
+#include "../include/raft.h"
+#include "request.h"
+
+void lifecycleRequestStart(struct raft *r, struct request *req);
+void lifecycleRequestEnd(struct raft *r, struct request *req);
+
+#endif

src/replication.c

@@ -9,6 +9,7 @@
 #endif
 #include "err.h"
 #include "heap.h"
+#include "lifecycle.h"
 #include "log.h"
 #include "membership.h"
 #include "progress.h"
@@ -454,7 +455,7 @@ static struct request *getRequest(struct raft *r,
         req = QUEUE_DATA(head, struct request, queue);
         if (req->index == index) {
             assert(req->type == type);
-            QUEUE_REMOVE(head);
+            lifecycleRequestEnd(r, req);
             return req;
         }
     }

src/request.h

@@ -10,6 +10,7 @@ struct request
     void *data;
     int type;
     raft_index index;
+    long id;
     void *queue[2];
 };