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<ol class="chapter"><li class="chapter-item expanded "><a href="../warpgrapher/intro.html"><strong aria-hidden="true">1.</strong> Warpgrapher</a></li><li class="chapter-item expanded "><a href="../warpgrapher/quickstart.html"><strong aria-hidden="true">2.</strong> Quickstart</a></li><li class="chapter-item expanded "><a href="../integrations/intro.html"><strong aria-hidden="true">3.</strong> Server Integration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../integrations/actix.html"><strong aria-hidden="true">3.1.</strong> Actix Web</a></li><li class="chapter-item expanded "><a href="../integrations/lambda.html" class="active"><strong aria-hidden="true">3.2.</strong> AWS Lambda</a></li></ol></li><li class="chapter-item expanded "><a href="../configuration/intro.html"><strong aria-hidden="true">4.</strong> Configuration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../configuration/databases.html"><strong aria-hidden="true">4.1.</strong> Databases</a></li><li class="chapter-item expanded "><a href="../configuration/formats.html"><strong aria-hidden="true">4.2.</strong> Formats</a></li><li class="chapter-item expanded "><a href="../configuration/types.html"><strong aria-hidden="true">4.3.</strong> Types</a></li><li class="chapter-item expanded "><a href="../configuration/relationships.html"><strong aria-hidden="true">4.4.</strong> Relationships</a></li></ol></li><li class="chapter-item expanded "><a href="../api/intro.html"><strong aria-hidden="true">5.</strong> CRUD API Usage Examples</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../api/node_create.html"><strong aria-hidden="true">5.1.</strong> Node Create</a></li><li class="chapter-item expanded "><a href="../api/node_read.html"><strong aria-hidden="true">5.2.</strong> Node Read</a></li><li class="chapter-item expanded "><a href="../api/node_update.html"><strong aria-hidden="true">5.3.</strong> Node Update</a></li><li class="chapter-item expanded "><a href="../api/node_delete.html"><strong aria-hidden="true">5.4.</strong> Node Delete</a></li><li class="chapter-item expanded "><a href="../api/rel_create.html"><strong aria-hidden="true">5.5.</strong> Relationship Create</a></li><li class="chapter-item expanded "><a href="../api/rel_read.html"><strong aria-hidden="true">5.6.</strong> Relationship Read</a></li><li class="chapter-item expanded "><a href="../api/rel_update.html"><strong aria-hidden="true">5.7.</strong> Relationship Update</a></li><li class="chapter-item expanded "><a href="../api/rel_delete.html"><strong aria-hidden="true">5.8.</strong> Relationship Delete</a></li></ol></li><li class="chapter-item expanded "><a href="../engine/intro.html"><strong aria-hidden="true">6.</strong> Engine Features</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../engine/endpoints_static.html"><strong aria-hidden="true">6.1.</strong> Static Endpoints</a></li><li class="chapter-item expanded "><a href="../engine/endpoints_defined.html"><strong aria-hidden="true">6.2.</strong> Defined Endpoints</a></li><li class="chapter-item expanded "><a href="../engine/dynamic_props.html"><strong aria-hidden="true">6.3.</strong> Dynamic Props</a></li><li class="chapter-item expanded "><a href="../engine/dynamic_rels.html"><strong aria-hidden="true">6.4.</strong> Dynamic Relationships</a></li><li class="chapter-item expanded "><a href="../engine/context_request.html"><strong aria-hidden="true">6.5.</strong> Request Context</a></li><li class="chapter-item expanded "><a href="../engine/input_validation.html"><strong aria-hidden="true">6.6.</strong> Input Validation</a></li><li class="chapter-item expanded "><a href="../engine/event_handlers.html"><strong aria-hidden="true">6.7.</strong> Event Handlers</a></li></ol></li></ol>
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<h1 class="menu-title">Warpgrapher Book (0.10.0)</h1>
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<h1 id="aws-lambda"><a class="header" href="#aws-lambda">AWS Lambda</a></h1>
<p>To integrate Warpgrapher with AWS lambda, begin by including the following dependencies in <code>Cargo.toml</code>. </p>
<p><code>Cargo.toml</code></p>
<pre><code class="language-toml">[dependencies]
lambda_runtime = "0.3.0"
serde = "1.0.57"
serde_json = "1.0.57"
serde_derive = "1.0.57"
tokio = { version="1.4.0", features=["rt-multi-thread", "macros"] }
warpgrapher = { version="0.10.0", features = ["gremlin"] }
</code></pre>
<p>In the <code>main.rs</code> source file, include the following code to include structs and functions that are needed from dependencies.</p>
<pre><code>use api_service::{create_app_engine, Error};
use lambda_runtime::handler_fn;
use serde_derive::Deserialize;
use serde_json::{json, Value};
use std::collections::HashMap;
use std::env::var_os;
use std::sync::Arc;
use warpgrapher::engine::database::gremlin::GremlinEndpoint;
use warpgrapher::engine::database::DatabaseEndpoint;
use warpgrapher::juniper::BoxFuture;
</code></pre>
<p>Next the lambda integration defines a <code>GraphqlRequest</code> struct that is used to deserialize query strings and request variables from the lambda interface for passing to the Warpgrapher engine.</p>
<pre><code>#[derive(Clone, Debug, Deserialize)]
pub struct GraphqlRequest {
pub query: String,
pub variables: Option<Value>,
}
</code></pre>
<p>The <code>AwsLambdaProxyRequest</code> struct is used to deserialize requests incoming from AWS lambda. Within the body of the request is the content that will be deserialized into the <code>GraphqlRequest</code> struct described above.</p>
<pre><code>#[derive(Clone, Debug, Deserialize)]
pub struct AwsLambdaProxyRequest {
pub body: String,
#[serde(rename = "requestContext")]
pub request_context: AwsLambdaProxyRequestContext,
}
</code></pre>
<p>The <code>aws_proxy_response</code> function below packages a result returned by a Warpgrapher engine's <code>execute</code> function into a format that can be returned to the AWS lambda framework.</p>
<pre><code>pub fn aws_proxy_response(body: serde_json::Value) -> Result<JSON, Error> {
Ok(json!({
"body": serde_json::to_string(&body)
.map_err(|e| Error::JsonSerializationError { source: e})?,
"headers": json!({}),
"isBase64Encoded": false,
"statusCode": 200
}))
}
</code></pre>
<p>The <code>create_app_engine</code> function takes a database pool, Gremlin in this example, and returns a Warpgrapher <code>Engine</code> that can be used to handle GraphQL queries.</p>
<pre><code> static CONFIG: &str = " version: 1
model:
- name: User
props:
- name: email
type: String
";
// create config
let config = Configuration::try_from(CONFIG.to_string()).expect("Failed to parse CONFIG");
// create warpgrapher engine
let engine: Engine<Rctx> = Engine::<Rctx>::new(config, db).build()?;
Ok(engine)
}
</code></pre>
<p>The <code>main</code> function ties the above elements together to process a GraphQL query when the lambda function is invoked. The function creates a database pool from environment variables, as described in the <a href="./configuration/databases.html">Databases</a> section of the book. The <code>main</code> function then uses the <code>create_app_engine</code> function to create a Warpgrapher <code>Engine</code>. A closure is defined that deserializes the request from the AWS lambda function and passes it to the Warpgrapher engine for execution using the <code>execute</code> method. The results are packaged up for response using the <code>aws_proxy_response</code> method. That handler closure is passed to the lambda runtime for invocation when requests need to be processed.</p>
<pre><code>#[tokio::main]
async fn main() -> Result<(), Error> {
// define database endpoint
let endpoint = GremlinEndpoint::from_env()?;
let db = endpoint.pool().await?;
// create warpgrapher engine
let engine = Arc::new(create_app_engine(db).await?);
let func = handler_fn(
move |event: Value, _: lambda_runtime::Context| -> BoxFuture<Result<Value, Error>> {
let eng = engine.clone();
Box::pin(async move {
let engine = eng.clone();
// parse handler event as aws proxy request and extract graphql request
let proxy_request = serde_json::from_value(event).map_err(|e|
Error::JsonDeserializationError {
desc: "Failed to deserialize aws proxy request".to_string(),
source: e,
})?;
let gql_request = serde_json::from_str(&proxy_request.body).map_err(|e|
Error::JsonDeserializationError {
desc: "Failed to deserialize graphql request in body".to_string(),
source: e,
})?;
// execute request
let result = engine
.execute(
gql_request.query.to_string(),
gql_request.variables,
HashMap::new(),
)
.await?;
// format response for api-gateway proxy
aws_proxy_response(result)
.or_else(|e| aws_proxy_response(json!({ "errors": [format!("{}", e)] })))
})
},
);
lambda_runtime::run(func)
.await
.map_err(|_| Error::LambdaError {})?;
Ok(())
}
</code></pre>
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