Add CLI command to generate an openapi schema

#1

src/cli/mod.rs

@@ -2,11 +2,16 @@ use async_trait::async_trait;
 use clap::{Parser, Subcommand};
 
 use crate::app_context::AppContext;
+#[cfg(feature = "open-api")]
 use crate::cli::list_routes::ListRoutesArgs;
+#[cfg(feature = "open-api")]
+use crate::cli::open_api_schema::OpenApiArgs;
 use crate::config::environment::Environment;
 
 #[cfg(feature = "open-api")]
 pub mod list_routes;
+#[cfg(feature = "open-api")]
+pub mod open_api_schema;
 
 /// Implement to enable Roadster to run your custom CLI commands.
 #[async_trait]
@@ -107,17 +112,24 @@ impl RunRoadsterCommand for RoadsterArgs {
 
 #[derive(Debug, Subcommand)]
 pub enum RoadsterSubCommand {
-    /// List the API routes available in the app. Note: this command will only list routes that
-    /// were defined using the `Aide` crate.
+    /// List the API routes available in the app. Note: only the routes defined
+    /// using the `Aide` crate will be included in the output.
     #[cfg(feature = "open-api")]
     ListRoutes(ListRoutesArgs),
+    /// Generate an OpenAPI 3.1 schema for the app's API routes. Note: only the routes defined
+    /// using the `Aide` crate will be included in the schema.
+    #[cfg(feature = "open-api")]
+    OpenApi(OpenApiArgs),
 }
 
 #[async_trait]
 impl RunRoadsterCommand for RoadsterSubCommand {
     async fn run(&self, cli: &RoadsterCli, context: &AppContext) -> anyhow::Result<bool> {
         match self {
+            #[cfg(feature = "open-api")]
             RoadsterSubCommand::ListRoutes(args) => args.run(cli, context).await,
+            #[cfg(feature = "open-api")]
+            RoadsterSubCommand::OpenApi(args) => args.run(cli, context).await,
         }
     }
 }

src/cli/open_api_schema.rs

@@ -0,0 +1,40 @@
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+use async_trait::async_trait;
+use clap::Parser;
+use tracing::info;
+
+use crate::app_context::AppContext;
+use crate::cli::{RoadsterCli, RunRoadsterCommand};
+
+#[derive(Debug, Parser)]
+pub struct OpenApiArgs {
+    /// The file to write the schema to. If not provided, will write to stdout.
+    #[clap(short, long, value_name = "FILE", value_hint = clap::ValueHint::FilePath)]
+    pub output: Option<PathBuf>,
+    /// Whether to pretty-print the schema. Default: false.
+    #[clap(short, long, default_value_t = false)]
+    pub pretty_print: bool,
+}
+
+#[async_trait]
+impl RunRoadsterCommand for OpenApiArgs {
+    async fn run(&self, _cli: &RoadsterCli, context: &AppContext) -> anyhow::Result<bool> {
+        let schema_json = if self.pretty_print {
+            serde_json::to_string_pretty(context.api.as_ref())?
+        } else {
+            serde_json::to_string(context.api.as_ref())?
+        };
+        if let Some(path) = &self.output {
+            info!("Writing schema to {:?}", path);
+            write!(File::create(path)?, "{schema_json}")?;
+        } else {
+            info!("OpenAPI schema:");
+            info!("{schema_json}");
+        };
+
+        Ok(true)
+    }
+}