[OpenAPI] Merge multiple paths in a single operation (#4415)

Author: swallez

Makefile

@@ -55,6 +55,9 @@ transform-to-openapi: ## Generate the OpenAPI definition from the compiled schem
 	@npm run transform-to-openapi -- --schema output/schema/schema.json --flavor stack --output output/openapi/elasticsearch-openapi.json
 	@npm run transform-to-openapi -- --schema output/schema/schema.json --flavor serverless --output output/openapi/elasticsearch-serverless-openapi.json
 
+transform-to-openapi-for-docs: ## Generate the OpenAPI definition tailored for API docs generation
+	@npm run transform-to-openapi -- --schema output/schema/schema.json --flavor stack --lift-enum-descriptions --merge-multipath-endpoints --output output/openapi/elasticsearch-openapi-docs.json
+
 filter-for-serverless: ## Generate the serverless version from the compiled schema
 	@npm run --prefix compiler filter-by-availability -- --serverless --visibility=public --input ../output/schema/schema.json --output ../output/output/openapi/elasticsearch-serverless-openapi.json
 

compiler-rs/clients_schema_to_openapi/src/cli.rs

@@ -20,13 +20,17 @@ pub struct Cli {
     #[argh(option, default = "SchemaFlavor::All")]
     pub flavor: SchemaFlavor,
 
-    /// add enum descriptions to property descriptions [default = true]
-    #[argh(option, default = "true")]
-    pub lift_enum_descriptions: bool,
-
     /// generate only this namespace (can be repeated)
     #[argh(option)]
     pub namespace: Vec<String>,
+
+    /// add enum descriptions to property descriptions [default = true]
+    #[argh(switch)]
+    pub lift_enum_descriptions: bool,
+
+    /// merge endpoints with multiple paths into a single OpenAPI operation [default = false]
+    #[argh(switch)]
+    pub merge_multipath_endpoints: bool,
 }
 
 use derive_more::FromStr;
@@ -42,20 +46,21 @@ pub enum SchemaFlavor {
 }
 
 impl From<Cli> for Configuration {
-    fn from(val: Cli) -> Configuration {
-        let flavor = match val.flavor {
+    fn from(cli: Cli) -> Configuration {
+        let flavor = match cli.flavor {
             SchemaFlavor::All => None,
             SchemaFlavor::Serverless => Some(Flavor::Serverless),
             SchemaFlavor::Stack => Some(Flavor::Stack),
         };
 
         Configuration {
             flavor,
-            lift_enum_descriptions: val.lift_enum_descriptions,
-            namespaces: if val.namespace.is_empty() {
+            lift_enum_descriptions: cli.lift_enum_descriptions,
+            merge_multipath_endpoints: cli.merge_multipath_endpoints,
+            namespaces: if cli.namespace.is_empty() {
                 None
             } else {
-                Some(val.namespace)
+                Some(cli.namespace)
             },
         }
     }

compiler-rs/clients_schema_to_openapi/src/lib.rs

@@ -32,7 +32,15 @@ use crate::components::TypesAndComponents;
 pub struct Configuration {
     pub flavor: Option<Flavor>,
     pub namespaces: Option<Vec<String>>,
+
+    /// If a property value is an enumeration, the description of possible values will be copied in the
+    /// property's description (also works for arrays of enums).
     pub lift_enum_descriptions: bool,
+
+    /// Will output endpoints having multiple paths into a single operation. The operation's path will
+    /// be the longest one (with values for all optional parameters), and the other paths will be added
+    /// at the beginning of the operation's description.
+    pub merge_multipath_endpoints: bool,
 }
 
 /// Convert an API model into an OpenAPI v3 schema, optionally filtered for a given flavor

compiler-rs/clients_schema_to_openapi/src/paths.rs

@@ -232,6 +232,67 @@ pub fn add_endpoint(
         // TODO: add error responses
     };
 
+    //---- Merge multipath endpoints if asked for
+    let mut new_endpoint: clients_schema::Endpoint;
+
+    let endpoint = if is_multipath && tac.config.merge_multipath_endpoints {
+        new_endpoint = endpoint.clone();
+        let endpoint = &mut new_endpoint;
+
+        // Sort paths from smallest to longest
+        endpoint.urls.sort_by_key(|x| x.path.len());
+
+        // Keep the longest and its last method so that the operation's path+method are the same as the last one
+        // (avoids the perception that it may have been chosen randomly).
+        let mut longest_path = endpoint.urls.last().unwrap().clone();
+        while longest_path.methods.len() > 1 {
+            longest_path.methods.remove(0);
+        }
+
+        // Replace endpoint urls with the longest path
+        let mut urls = vec![longest_path];
+        std::mem::swap(&mut endpoint.urls, &mut urls);
+
+        let split_desc = split_summary_desc(&endpoint.description);
+
+        // Make sure the description is stays at the top
+        let mut description = match split_desc.summary {
+            Some(summary) => format!("{summary}\n\n"),
+            None => String::new(),
+        };
+
+        // Convert removed paths to descriptions
+        write!(description, "**All methods and paths for this operation:**\n\n")?;
+
+        for url in urls {
+            for method in url.methods {
+                let lower_method = method.to_lowercase();
+                let path = &url.path;
+                write!(
+                    description,
+                    r#"<div>
+                      <span class="operation-verb {lower_method}">{method}</span>
+                      <span class="operation-path">{path}</span>
+                      </div>
+                    "#
+                )?;
+            }
+        }
+
+        if let Some(desc) = &split_desc.description {
+            write!(description, "\n\n{}", desc)?;
+        }
+
+        // Replace description
+        endpoint.description = description;
+
+        // Done
+        endpoint
+    } else {
+        // Not multipath or not asked to merge multipath
+        endpoint
+    };
+
     //---- Build a path for each url + method
     let mut operation_counter = 0;