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feat: serde dynamo #40

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feat: serde dynamo #40

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20e5a78
add serde_dynamo alpha
hffmnn Feb 4, 2022
3d3fa1b
use from_item and from_items
hffmnn Feb 4, 2022
826ffdd
use to_item
hffmnn Feb 4, 2022
a365ed0
remove From and TryFrom
hffmnn Feb 4, 2022
7ab0e12
use from_attribute_value
hffmnn Feb 4, 2022
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9 changes: 8 additions & 1 deletion Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,13 @@ tracing = "0.1"
tracing-subscriber = { version = "0.2", features = ["fmt", "json"] }
tokio = { version = "1", features = ["full"] }

[dependencies.serde_dynamo]
git = "https://github.com/sciguy16/serde_dynamo.git"
branch = "aws-0_5"
features = ["aws-sdk-dynamodb+0_6"]
version = "3.0.0-alpha"
optional = true

[dev-dependencies]
# Only allow hardcoded credentials for unit tests
aws-types = { version = "0.4", features = ["hardcoded-credentials"] }
Expand All @@ -32,7 +39,7 @@ reqwest = { version = "0.11", features = ["json"] }

[features]
default = ["lambda"]
lambda = ["lambda_runtime", "lambda_http", "rayon"]
lambda = ["lambda_runtime", "lambda_http", "rayon", "serde_dynamo"]

[[bin]]
name = "delete-product"
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85 changes: 0 additions & 85 deletions src/store/dynamodb/ext.rs
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64 changes: 15 additions & 49 deletions src/store/dynamodb/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,12 +6,9 @@ use super::{Store, StoreDelete, StoreGet, StoreGetAll, StorePut};
use crate::{Error, Product, ProductRange};
use async_trait::async_trait;
use aws_sdk_dynamodb::{model::AttributeValue, Client};
use std::collections::HashMap;
use serde_dynamo::aws_sdk_dynamodb_0_6::{from_attribute_value, from_item, from_items, to_item};
use tracing::{info, instrument};

mod ext;
use ext::AttributeValuesExt;

/// DynamoDB store implementation.
pub struct DynamoDBStore {
client: Client,
Expand Down Expand Up @@ -42,14 +39,15 @@ impl StoreGetAll for DynamoDBStore {
let res = req.send().await?;

// Build response
let products = match res.items {
Some(items) => items
.into_iter()
.map(|v| v.try_into())
.collect::<Result<Vec<Product>, Error>>()?,
let products: Vec<Product> = match res.items {
Some(items) => from_items(items).map_err(|_|
// TODO: Find out correct error from underlying error?
Error::InternalError("Missing name"))?,
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This already shows a problem: How to map the underlying error to our very specific error Missing name. I don't think that the underlying serde errors give us that info: https://github.com/zenlist/serde_dynamo/blob/3.0.0-alpha/src/error.rs

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Looking into the source code, it looks like it just uses serde_dynamo::ErrorImpl::Message, which might contain the right message - but that's not a guarantee. The best thing would be to write a small sample using the Product struct and serde_dynamo.

None => Vec::default(),
};
let next = res.last_evaluated_key.map(|m| m.get_s("id").unwrap());
let next = res
.last_evaluated_key
.map(|m| from_attribute_value(m["id"].clone()).unwrap());
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Not sure if there is a more elegant way to write this?

Ok(ProductRange { products, next })
}
}
Expand All @@ -69,7 +67,8 @@ impl StoreGet for DynamoDBStore {
.await?;

Ok(match res.item {
Some(item) => Some(item.try_into()?),
// TODO: Find out correct error from underlying error?
Some(item) => from_item(item).map_err(|_| Error::InternalError("Missing name"))?,
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Same problem as above.

None => None,
})
}
Expand All @@ -84,7 +83,8 @@ impl StorePut for DynamoDBStore {
self.client
.put_item()
.table_name(&self.table_name)
.set_item(Some(product.into()))
// TODO: Can this fail?
.set_item(Some(to_item(product).unwrap()))
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We still have a unit test for that, so we tested that to_item can serialize a product.

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That shouldn't fail since all the fields in a product map to valid DynamoDB attributes.

.send()
.await?;

Expand All @@ -109,48 +109,14 @@ impl StoreDelete for DynamoDBStore {
}
}

impl From<&Product> for HashMap<String, AttributeValue> {
/// Convert a &Product into a DynamoDB item
fn from(value: &Product) -> HashMap<String, AttributeValue> {
let mut retval = HashMap::new();
retval.insert("id".to_owned(), AttributeValue::S(value.id.clone()));
retval.insert("name".to_owned(), AttributeValue::S(value.name.clone()));
retval.insert(
"price".to_owned(),
AttributeValue::N(format!("{:}", value.price)),
);

retval
}
}
impl TryFrom<HashMap<String, AttributeValue>> for Product {
type Error = Error;

/// Try to convert a DynamoDB item into a Product
///
/// This could fail as the DynamoDB item might be missing some fields.
fn try_from(value: HashMap<String, AttributeValue>) -> Result<Self, Self::Error> {
Ok(Product {
id: value
.get_s("id")
.ok_or(Error::InternalError("Missing id"))?,
name: value
.get_s("name")
.ok_or(Error::InternalError("Missing name"))?,
price: value
.get_n("price")
.ok_or(Error::InternalError("Missing price"))?,
})
}
}

#[cfg(test)]
mod tests {
use super::*;
use crate::Error;
use aws_sdk_dynamodb::{Client, Config, Credentials, Region};
use aws_smithy_client::{erase::DynConnector, test_connection::TestConnection};
use aws_smithy_http::body::SdkBody;
use std::collections::HashMap;

/// Config for mocking DynamoDB
async fn get_mock_config() -> Config {
Expand Down Expand Up @@ -368,7 +334,7 @@ mod tests {
value.insert("name".to_owned(), AttributeValue::S("name".to_owned()));
value.insert("price".to_owned(), AttributeValue::N("1.0".to_owned()));

let product = Product::try_from(value).unwrap();
let product: Product = from_item(value).unwrap();
assert_eq!(product.id, "id");
assert_eq!(product.name, "name");
assert_eq!(product.price, 1.0);
Expand All @@ -382,7 +348,7 @@ mod tests {
price: 1.5,
};

let value: HashMap<String, AttributeValue> = (&product).into();
let value: HashMap<String, AttributeValue> = to_item(product).unwrap();
assert_eq!(value.get("id").unwrap().as_s().unwrap(), "id");
assert_eq!(value.get("name").unwrap().as_s().unwrap(), "name");
assert_eq!(value.get("price").unwrap().as_n().unwrap(), "1.5");
Expand Down