add motoko timer example

dfinity · May 23, 2024 · 818c400 · 818c400
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diff --git a/motoko/canister_logs/README.md b/motoko/canister_logs/README.md
@@ -38,13 +38,17 @@ $ cd examples/motoko/canister_logs
 $ dfx deploy
 ```
 
-### Step 3: Check canister has no logs yet:
+### Step 3: Check canister logs:
+
+Expect to see logs from timer traps.
 
 ```shell
 # Terminal B
 $ dfx canister logs CanisterLogs
-
-# Expect to see no logs.
+[0. 2024-05-23T08:14:40.60349175Z]: right before timer trap
+[1. 2024-05-23T08:14:40.60349175Z]: [TRAP]: timer trap
+[2. 2024-05-23T08:14:46.160555676Z]: right before timer trap
+[3. 2024-05-23T08:14:46.160555676Z]: [TRAP]: timer trap
 ```
 
 ### Step 4: Call `print` method and check the logs:
@@ -56,7 +60,13 @@ $ dfx canister call CanisterLogs print hi
 
 # Expect to see new log entry.
 $ dfx canister logs CanisterLogs
-[0. 2024-05-22T11:37:28.080234848Z]: hi
+...
+[14. 2024-05-23T08:15:15.829022842Z]: right before timer trap
+[15. 2024-05-23T08:15:15.829022842Z]: [TRAP]: timer trap
+[16. 2024-05-23T08:15:19.728382106Z]: hi
+[17. 2024-05-23T08:15:21.079923035Z]: right before timer trap
+[18. 2024-05-23T08:15:21.079923035Z]: [TRAP]: timer trap
+...
 ```
 
 ### Step 5: Start constantly polling logs:
@@ -66,8 +76,13 @@ In order not to call `dfx canister logs CanisterLogs` after every canister call
 ```shell
 # Terminal C
 $ ./poll_logs.sh
-[0. 2024-05-22T11:37:28.080234848Z]: hi
-
+...
+[14. 2024-05-23T08:15:15.829022842Z]: right before timer trap
+[15. 2024-05-23T08:15:15.829022842Z]: [TRAP]: timer trap
+[16. 2024-05-23T08:15:19.728382106Z]: hi
+[17. 2024-05-23T08:15:21.079923035Z]: right before timer trap
+[18. 2024-05-23T08:15:21.079923035Z]: [TRAP]: timer trap
+...
 ```
 
 ### Step 6: Call `print`, `trap`, `panic` and other canister methods:
@@ -94,10 +109,24 @@ Observe recorded logs that might look similar to this:
 
 ```shell
 # Terminal C
-[0. 2024-05-22T12:21:52.333589617Z]: hi
-[1. 2024-05-22T12:22:27.330332077Z]: hello!
-[2. 2024-05-22T12:22:32.062734677Z]: yey!
-[3. 2024-05-22T12:22:36.685104375Z]: right before trap
-[4. 2024-05-22T12:22:36.685104375Z]: [TRAP]: oops!
+...
+[49. 2024-05-23T08:16:40.702368542Z]: right before timer trap
+[50. 2024-05-23T08:16:40.702368542Z]: [TRAP]: timer trap
+[51. 2024-05-23T08:16:42.785727368Z]: hi!
+[52. 2024-05-23T08:16:45.69960063Z]: right before timer trap
+[53. 2024-05-23T08:16:45.69960063Z]: [TRAP]: timer trap
+[54. 2024-05-23T08:16:47.222911354Z]: hello!
+[55. 2024-05-23T08:16:50.875445893Z]: right before timer trap
+[56. 2024-05-23T08:16:50.875445893Z]: [TRAP]: timer trap
+[57. 2024-05-23T08:16:51.570602735Z]: yey!
+[58. 2024-05-23T08:16:55.783308056Z]: right before timer trap
+[59. 2024-05-23T08:16:55.783308056Z]: [TRAP]: timer trap
+[60. 2024-05-23T08:16:56.536701165Z]: right before trap
+[61. 2024-05-23T08:16:56.536701165Z]: [TRAP]: oops!
+[62. 2024-05-23T08:17:00.759041661Z]: right before timer trap
+[63. 2024-05-23T08:17:00.759041661Z]: [TRAP]: timer trap
+[64. 2024-05-23T08:17:05.657467481Z]: right before timer trap
+[65. 2024-05-23T08:17:05.657467481Z]: [TRAP]: timer trap
+...
 
 ```
diff --git a/motoko/canister_logs/src/Main.mo b/motoko/canister_logs/src/Main.mo
@@ -1,7 +1,23 @@
 import Debug "mo:base/Debug";
+import { abs } = "mo:base/Int";
+import { now } = "mo:base/Time";
+import { setTimer; recurringTimer } = "mo:base/Timer";
 
 actor CanisterLogs {
 
+  let timerDelaySeconds = 5;
+
+  private func execute_timer() : async () {
+    Debug.print("right before timer trap");
+    Debug.trap("timer trap");
+  };
+
+  ignore setTimer<system>(#seconds (timerDelaySeconds - abs(now() / 1_000_000_000) % timerDelaySeconds),
+    func () : async () {
+      ignore recurringTimer<system>(#seconds timerDelaySeconds, execute_timer);
+      await execute_timer();
+  });
+
   public func print(text : Text) : async () {
     Debug.print(text);
   };

diff --git a/rust/canister_logs/README.md b/rust/canister_logs/README.md
@@ -62,15 +62,11 @@ $ dfx canister call canister_logs print hi
 # Expect to see new log entry.
 $ dfx canister logs canister_logs
 ...
-[16. 2024-05-22T12:36:15.638667167Z]: right before timer trap
-[17. 2024-05-22T12:36:15.638667167Z]: [TRAP]: timer trap
 [18. 2024-05-22T12:36:20.881326098Z]: right before timer trap
 [19. 2024-05-22T12:36:20.881326098Z]: [TRAP]: timer trap
 [20. 2024-05-22T12:36:26.305162772Z]: hi
 [21. 2024-05-22T12:36:27.185879186Z]: right before timer trap
 [22. 2024-05-22T12:36:27.185879186Z]: [TRAP]: timer trap
-[23. 2024-05-22T12:36:33.486805581Z]: right before timer trap
-[24. 2024-05-22T12:36:33.486805581Z]: [TRAP]: timer trap
 ```
 
 ### Step 5: Start constantly polling logs:
@@ -81,17 +77,12 @@ In order not to call `dfx canister logs canister_logs` after every canister call
 # Terminal C
 $ ./poll_logs.sh
 ...
-[16. 2024-05-22T12:36:15.638667167Z]: right before timer trap
-[17. 2024-05-22T12:36:15.638667167Z]: [TRAP]: timer trap
 [18. 2024-05-22T12:36:20.881326098Z]: right before timer trap
 [19. 2024-05-22T12:36:20.881326098Z]: [TRAP]: timer trap
 [20. 2024-05-22T12:36:26.305162772Z]: hi
 [21. 2024-05-22T12:36:27.185879186Z]: right before timer trap
 [22. 2024-05-22T12:36:27.185879186Z]: [TRAP]: timer trap
-[23. 2024-05-22T12:36:33.486805581Z]: right before timer trap
-[24. 2024-05-22T12:36:33.486805581Z]: [TRAP]: timer trap
 ...
-
 ```
 
 ### Step 6: Call `print`, `trap`, `panic` and other canister methods: