Document XREAD of last message (+) (#3188)

XREAD now supports reading the last message in the stream, with the + special Id. The code already supports this, so just add some documentation to an existing Jupyter notebook. Fixes #3155 Co-authored-by: Gabriel Erzse <[email protected]>
redis · May 15, 2024 · 0b20087 · 0b20087
1 parent 68d6d53
commit 0b20087
Showing 1 changed file with 65 additions and 37 deletions.
diff --git a/docs/examples/redis-stream-example.ipynb b/docs/examples/redis-stream-example.ipynb
@@ -108,7 +108,7 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "[[b'skey', [(b'1657571033115-0', {b'ts': b'1657571033.1128936', b'v': b'0'}), (b'1657571033117-0', {b'ts': b'1657571033.1176307', b'v': b'1'})]]]\n"
+      "[[b'skey', [(b'1710790167982-0', {b'ts': b'1710790167.9824948', b'v': b'0'}), (b'1710790167983-0', {b'ts': b'1710790167.9830241', b'v': b'1'})]]]\n"
      ]
     }
    ],
@@ -135,8 +135,8 @@
      "output_type": "stream",
      "text": [
       "got data from stream: b'skey'\n",
-      "id: b'1657571033115-0' value: b'0'\n",
-      "id: b'1657571033117-0' value: b'1'\n"
+      "id: b'1710790167982-0' value: b'0'\n",
+      "id: b'1710790167983-0' value: b'1'\n"
      ]
     }
    ],
@@ -165,8 +165,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "id: b'1657571033115-0' value: b'0'\n",
-      "id: b'1657571033117-0' value: b'1'\n"
+      "id: b'1710790167982-0' value: b'0'\n",
+      "id: b'1710790167983-0' value: b'1'\n"
      ]
     }
    ],
@@ -192,8 +192,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "id: b'1657571033118-0' value: b'2'\n",
-      "id: b'1657571033119-0' value: b'3'\n"
+      "id: b'1710790167983-1' value: b'2'\n",
+      "id: b'1710790167983-2' value: b'3'\n"
      ]
     }
    ],
@@ -213,8 +213,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "id: b'1657571033119-1' value: b'4'\n",
-      "id: b'1657571033121-0' value: b'5'\n"
+      "id: b'1710790167983-3' value: b'4'\n",
+      "id: b'1710790167983-4' value: b'5'\n"
      ]
     }
    ],
@@ -255,6 +255,34 @@
     "print( f\"stream length: {r.xlen( stream_key )}\")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "source": [
+    "to get the last entry in the stream"
+   ],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[[b'skey', [(b'1710790167984-0', {b'ts': b'1710790167.9839962', b'v': b'9'})]]]\n",
+      "stream length: 10\n"
+     ]
+    }
+   ],
+   "source": [
+    "# read the last available message\n",
+    "l = r.xread( count=1, streams={stream_key: '+'} )\n",
+    "print(l)\n",
+    "print( f\"stream length: {r.xlen( stream_key )}\")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -298,8 +326,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "got from b'skey' the entry [(b'1657571033115-0', {b'ts': b'1657571033.1128936', b'v': b'0'})]\n",
-      "got from b's2key' the entry [(b'1657571042111-0', {b'v': b'1000'})]\n"
+      "got from b'skey' the entry [(b'1710790167982-0', {b'ts': b'1710790167.9824948', b'v': b'0'})]\n",
+      "got from b's2key' the entry [(b'1710790173142-0', {b'v': b'1000'})]\n"
      ]
     }
    ],
@@ -425,8 +453,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "got element b'1657571033115-0'from stream b'skey'\n",
-      "got element b'1657571033117-0'from stream b'skey'\n"
+      "got element b'1710790167982-0'from stream b'skey'\n",
+      "got element b'1710790167983-0'from stream b'skey'\n"
      ]
     }
    ],
@@ -453,8 +481,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "got element b'1657571033118-0'from stream b'skey'\n",
-      "got element b'1657571033119-0'from stream b'skey'\n"
+      "got element b'1710790167983-1'from stream b'skey'\n",
+      "got element b'1710790167983-2'from stream b'skey'\n"
      ]
     }
    ],
@@ -484,10 +512,10 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "got element b'1657571033115-0'from stream b'skey'\n",
-      "got element b'1657571033117-0'from stream b'skey'\n",
-      "got element b'1657571042111-0'from stream b's2key'\n",
-      "got element b'1657571042113-0'from stream b's2key'\n"
+      "got element b'1710790167982-0'from stream b'skey'\n",
+      "got element b'1710790167983-0'from stream b'skey'\n",
+      "got element b'1710790173142-0'from stream b's2key'\n",
+      "got element b'1710790173143-0'from stream b's2key'\n"
      ]
     }
    ],
@@ -546,8 +574,8 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "got element b'1657571033118-0'from stream b'skey'\n",
-      "got element b'1657571033119-0'from stream b'skey'\n"
+      "got element b'1710790167983-1'from stream b'skey'\n",
+      "got element b'1710790167983-2'from stream b'skey'\n"
      ]
     }
    ],
@@ -593,22 +621,22 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "got element b'1657571033119-1'from stream b'skey'\n",
-      "got element b'1657571033121-0'from stream b'skey'\n",
-      "got element b'1657571033121-1'from stream b'skey'\n",
-      "got element b'1657571033121-2'from stream b'skey'\n",
-      "got element b'1657571033122-0'from stream b'skey'\n",
-      "got element b'1657571033122-1'from stream b'skey'\n",
-      "got element b'1657571049557-0'from stream b'skey'\n",
-      "got element b'1657571049557-1'from stream b'skey'\n",
-      "got element b'1657571049558-0'from stream b'skey'\n",
-      "got element b'1657571049559-0'from stream b'skey'\n",
-      "got element b'1657571049559-1'from stream b'skey'\n",
-      "got element b'1657571049559-2'from stream b'skey'\n",
-      "got element b'1657571049560-0'from stream b'skey'\n",
-      "got element b'1657571049562-0'from stream b'skey'\n",
-      "got element b'1657571049563-0'from stream b'skey'\n",
-      "got element b'1657571049563-1'from stream b'skey'\n",
+      "got element b'1710790167983-3'from stream b'skey'\n",
+      "got element b'1710790167983-4'from stream b'skey'\n",
+      "got element b'1710790167983-5'from stream b'skey'\n",
+      "got element b'1710790167983-6'from stream b'skey'\n",
+      "got element b'1710790167983-7'from stream b'skey'\n",
+      "got element b'1710790167984-0'from stream b'skey'\n",
+      "got element b'1710790173157-0'from stream b'skey'\n",
+      "got element b'1710790173158-0'from stream b'skey'\n",
+      "got element b'1710790173158-1'from stream b'skey'\n",
+      "got element b'1710790173158-2'from stream b'skey'\n",
+      "got element b'1710790173158-3'from stream b'skey'\n",
+      "got element b'1710790173158-4'from stream b'skey'\n",
+      "got element b'1710790173158-5'from stream b'skey'\n",
+      "got element b'1710790173159-0'from stream b'skey'\n",
+      "got element b'1710790173159-1'from stream b'skey'\n",
+      "got element b'1710790173159-2'from stream b'skey'\n",
       "2 pending messages on 'skey' for group 'grp1'\n"
      ]
     }