Merge pull request #4 from delta-incubator/leaseDuration-3

Set the TTL attribute properly

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "dynamodb_lock"
 description = "Distributed lock backed by Dynamodb"
-version = "0.5.0"
+version = "0.6.0"
 authors = [
     "Mykhailo Osypov <[email protected]>",
     "R Tyler Croy <[email protected]>",
@@ -26,6 +26,9 @@ rusoto_sts = { version ="0.47", default-features = false, optional = true }
 maplit = "1"
 tokio = { version = "1", features = ["fs", "macros", "rt", "io-util"] }
 
+[dev-dependencies]
+pretty_env_logger = "*"
+
 [features]
 default = ["rustls"]
 sts = ["rusoto_sts",

README.md

@@ -14,14 +14,12 @@ Usage
 -----
 
 ```rust
-let dynamodb_client = rusoto_dynamodb::DynamoDbClient::new(rusoto_core::Region::default());
-let lock_client = dynamodb_lock::DynamoDbLockClient::new(
-    dynamodb_client,
-    dynamodb_lock::DynamoDbOptions::default(),
-);
+let region = dynamodb_lock::Region::default();
+// This will use the default options
+let lock_client = dynamodb_lock::DynamoDbLockClient::for_region(region);
 
 let lock_data = "Moe";
-let lock = lock_client.try_acquire_lock(lock_data).await?.unwrap();
+let lock = lock_client.try_acquire_lock(Some(lock_data)).await?.unwrap();
 
 if lock.acquired_expired_lock {
     // error handling when acquired an expired lock

examples/demo.rs

@@ -0,0 +1,23 @@
+use dynamodb_lock::*;
+
+#[tokio::main]
+async fn main() -> Result<(), DynamoError> {
+    pretty_env_logger::init();
+    let region = Region::default();
+    // This will use the default options
+    let lock_client = DynamoDbLockClient::for_region(region);
+
+    let lock_data = "Moe";
+    let lock = lock_client
+        .try_acquire_lock(Some(lock_data))
+        .await?
+        .unwrap();
+
+    if lock.acquired_expired_lock {
+        // error handling when acquired an expired lock
+    }
+
+    // do stuff in the critical region
+    lock_client.release_lock(&lock).await?;
+    Ok(())
+}

src/lib.rs

@@ -533,7 +533,7 @@ impl DynamoDbLockClient {
             PARTITION_KEY_NAME.to_string() => attr(self.opts.partition_key_value.clone()),
             OWNER_NAME.to_string() => attr(&self.opts.owner_name),
             RECORD_VERSION_NUMBER.to_string() => attr(&rvn),
-            LEASE_DURATION.to_string() => attr(self.opts.lease_duration),
+            LEASE_DURATION.to_string() => num_attr(lease_duration_after(self.opts.lease_duration)),
         };
 
         if let Some(d) = data {
@@ -590,6 +590,15 @@ impl DynamoDbLockClient {
     }
 }
 
+/// Return a u64 lease duration the given seconds from the current time
+fn lease_duration_after(after: u64) -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap()
+        .as_secs()
+        + after
+}
+
 fn now_millis() -> u128 {
     SystemTime::now()
         .duration_since(UNIX_EPOCH)
@@ -605,6 +614,13 @@ fn attr<T: ToString>(s: T) -> AttributeValue {
     }
 }
 
+fn num_attr<T: ToString>(s: T) -> AttributeValue {
+    AttributeValue {
+        n: Some(s.to_string()),
+        ..Default::default()
+    }
+}
+
 fn get_string(attr: Option<&AttributeValue>) -> Result<String, DynamoError> {
     Ok(attr
         .and_then(|r| r.s.as_ref())
@@ -843,4 +859,30 @@ mod tests {
             options
         );
     }
+
+    #[test]
+    fn test_lease_duration_after() {
+        use std::time::SystemTime;
+        let now = match SystemTime::now().duration_since(SystemTime::UNIX_EPOCH) {
+            Ok(n) => n.as_secs(),
+            Err(_) => panic!("SystemTime before UNIX EPOCH!"),
+        };
+        let duration: u64 = lease_duration_after(60);
+
+        assert!(duration > now);
+        assert!(duration >= (now + 60));
+        assert!(duration <= (now + 70));
+    }
+
+    #[test]
+    fn test_lease_duration_attr() {
+        let n = num_attr(1);
+        assert!(n.n.is_some());
+        if let Some(num) = n.n {
+            assert_eq!(1, num.parse::<u64>().unwrap());
+        } else {
+            println!("attr {n:?}");
+            assert!(false);
+        }
+    }
 }