Metadata: Retain a subset of metadata pallets

cli/src/commands/codegen.rs

@@ -3,24 +3,19 @@
 // see LICENSE for license details.
 
 use clap::Parser as ClapParser;
-use color_eyre::eyre;
-use jsonrpsee::client_transport::ws::Uri;
-use std::{fs, io::Read, path::PathBuf};
 use subxt_codegen::{DerivesRegistry, TypeSubstitutes};
 
+use super::utils::FileOrUrl;
+
 /// Generate runtime API client code from metadata.
 ///
 /// # Example (with code formatting)
 ///
 /// `subxt codegen | rustfmt --edition=2018 --emit=stdout`
 #[derive(Debug, ClapParser)]
 pub struct Opts {
-    /// The url of the substrate node to query for metadata for codegen.
-    #[clap(name = "url", long, value_parser)]
-    url: Option<Uri>,
-    /// The path to the encoded metadata file.
-    #[clap(short, long, value_parser)]
-    file: Option<PathBuf>,
+    #[command(flatten)]
+    file_or_url: FileOrUrl,
     /// Additional derives
     #[clap(long = "derive")]
     derives: Vec<String>,
@@ -52,23 +47,7 @@ fn derive_for_type_parser(src: &str) -> Result<(String, String), String> {
 }
 
 pub async fn run(opts: Opts) -> color_eyre::Result<()> {
-    let bytes = if let Some(file) = opts.file.as_ref() {
-        if opts.url.is_some() {
-            eyre::bail!("specify one of `--url` or `--file` but not both")
-        };
-
-        let mut file = fs::File::open(file)?;
-        let mut bytes = Vec::new();
-        file.read_to_end(&mut bytes)?;
-        bytes
-    } else {
-        let url = opts.url.unwrap_or_else(|| {
-            "http://localhost:9933"
-                .parse::<Uri>()
-                .expect("default url is valid")
-        });
-        subxt_codegen::utils::fetch_metadata_bytes(&url).await?
-    };
+    let bytes = opts.file_or_url.fetch().await?;
 
     codegen(
         &bytes,

cli/src/commands/metadata.rs

@@ -4,45 +4,58 @@
 
 use clap::Parser as ClapParser;
 use color_eyre::eyre;
-use frame_metadata::RuntimeMetadataPrefixed;
-use jsonrpsee::client_transport::ws::Uri;
-use scale::Decode;
+use frame_metadata::{RuntimeMetadata, RuntimeMetadataPrefixed};
+use scale::{Decode, Encode};
 use std::io::{self, Write};
-use subxt_codegen::utils::fetch_metadata_hex;
+use subxt_metadata::retain_metadata_pallets;
+
+use super::utils::FileOrUrl;
 
 /// Download metadata from a substrate node, for use with `subxt` codegen.
 #[derive(Debug, ClapParser)]
 pub struct Opts {
-    /// The url of the substrate node to query for metadata.
-    #[clap(
-        name = "url",
-        long,
-        value_parser,
-        default_value = "http://localhost:9933"
-    )]
-    url: Uri,
+    #[command(flatten)]
+    file_or_url: FileOrUrl,
     /// The format of the metadata to display: `json`, `hex` or `bytes`.
     #[clap(long, short, default_value = "bytes")]
     format: String,
+    /// Generate a subset of the metadata that contains only the
+    /// types needed to represent the provided pallets.
+    #[clap(long, use_value_delimiter = true, value_parser)]
+    pallets: Option<Vec<String>>,
 }
 
 pub async fn run(opts: Opts) -> color_eyre::Result<()> {
-    let hex_data = fetch_metadata_hex(&opts.url).await?;
+    let bytes = opts.file_or_url.fetch().await?;
+    let mut metadata = <RuntimeMetadataPrefixed as Decode>::decode(&mut &bytes[..])?;
+
+    if let Some(pallets) = opts.pallets {
+        let metadata_v14 = match &mut metadata.1 {
+            RuntimeMetadata::V14(metadata_v14) => metadata_v14,
+            _ => {
+                return Err(eyre::eyre!(
+                    "Unsupported metadata version {:?}, expected V14.",
+                    metadata.1
+                ))
+            }
+        };
+
+        retain_metadata_pallets(metadata_v14, |pallet| pallets.contains(&pallet.name));
+    }
 
     match opts.format.as_str() {
         "json" => {
-            let bytes = hex::decode(hex_data.trim_start_matches("0x"))?;
-            let metadata = <RuntimeMetadataPrefixed as Decode>::decode(&mut &bytes[..])?;
             let json = serde_json::to_string_pretty(&metadata)?;
             println!("{json}");
             Ok(())
         }
         "hex" => {
+            let hex_data = format!("0x{:?}", hex::encode(metadata.encode()));
             println!("{hex_data}");
             Ok(())
         }
         "bytes" => {
-            let bytes = hex::decode(hex_data.trim_start_matches("0x"))?;
+            let bytes = metadata.encode();
             Ok(io::stdout().write_all(&bytes)?)
         }
         _ => Err(eyre::eyre!(

cli/src/commands/mod.rs

@@ -5,4 +5,5 @@
 pub mod codegen;
 pub mod compatibility;
 pub mod metadata;
+mod utils;
 pub mod version;

cli/src/commands/utils.rs

@@ -0,0 +1,43 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+use clap::Args;
+use std::{fs, io::Read, path::PathBuf};
+
+use color_eyre::eyre;
+use subxt_codegen::utils::Uri;
+
+/// The source of the metadata.
+#[derive(Debug, Args)]
+pub struct FileOrUrl {
+    /// The url of the substrate node to query for metadata for codegen.
+    #[clap(name = "url", long, value_parser)]
+    url: Option<Uri>,
+    /// The path to the encoded metadata file.
+    #[clap(short, long, value_parser)]
+    file: Option<PathBuf>,
+}
+
+impl FileOrUrl {
+    /// Fetch the metadata bytes.
+    pub async fn fetch(&self) -> color_eyre::Result<Vec<u8>> {
+        if let Some(path) = &self.file {
+            if self.url.is_some() {
+                eyre::bail!("specify one of `--url` or `--file` but not both")
+            };
+
+            let mut file = fs::File::open(path)?;
+            let mut bytes = Vec::new();
+            file.read_to_end(&mut bytes)?;
+            return Ok(bytes);
+        }
+
+        let url = self.url.clone().unwrap_or_else(|| {
+            "http://localhost:9933"
+                .parse::<Uri>()
+                .expect("default url is valid")
+        });
+        Ok(subxt_codegen::utils::fetch_metadata_bytes(&url).await?)
+    }
+}

codegen/Cargo.toml

@@ -20,7 +20,7 @@ heck = "0.4.1"
 proc-macro2 = "1.0.54"
 quote = "1.0.8"
 syn = "1.0.109"
-scale-info = "2.4.0"
+scale-info = "2.5.0"
 subxt-metadata = { version = "0.27.1", path = "../metadata" }
 jsonrpsee = { version = "0.16.0", features = ["async-client", "client-ws-transport", "http-client"] }
 hex = "0.4.3"
@@ -29,5 +29,5 @@ thiserror = "1.0.40"
 
 [dev-dependencies]
 bitvec = { version = "1.0.0", default-features = false, features = ["alloc"] }
-scale-info = { version = "2.4.0", features = ["bit-vec"] }
+scale-info = { version = "2.5.0", features = ["bit-vec"] }
 pretty_assertions = "1.0.0"

codegen/src/api/calls.rs

@@ -37,7 +37,7 @@ pub fn generate_calls(
 
     let mut struct_defs = super::generate_structs_from_variants(
         type_gen,
-        call.ty.id(),
+        call.ty.id,
         |name| name.to_upper_camel_case().into(),
         "Call",
         crate_path,
@@ -61,7 +61,7 @@ pub fn generate_calls(
                     .unzip(),
                 CompositeDefFields::NoFields => Default::default(),
                 CompositeDefFields::Unnamed(_) => {
-                    return Err(CodegenError::InvalidCallVariant(call.ty.id()))
+                    return Err(CodegenError::InvalidCallVariant(call.ty.id))
                 }
             };
 
@@ -106,8 +106,8 @@ pub fn generate_calls(
         .into_iter()
         .unzip();
 
-    let call_ty = type_gen.resolve_type(call.ty.id());
-    let docs = call_ty.docs();
+    let call_ty = type_gen.resolve_type(call.ty.id);
+    let docs = call_ty.docs;
     let docs = should_gen_docs
         .then_some(quote! { #( #[doc = #docs ] )* })
         .unwrap_or_default();

codegen/src/api/constants.rs

@@ -56,7 +56,7 @@ pub fn generate_constants(
             return Err(CodegenError::MissingConstantMetadata(constant_name.into(), pallet_name.into()));
         };
 
-        let return_ty = type_gen.resolve_type_path(constant.ty.id());
+        let return_ty = type_gen.resolve_type_path(constant.ty.id);
         let docs = &constant.docs;
         let docs = should_gen_docs
             .then_some(quote! { #( #[doc = #docs ] )* })

codegen/src/api/events.rs

@@ -53,7 +53,7 @@ pub fn generate_events(
 
     let struct_defs = super::generate_structs_from_variants(
         type_gen,
-        event.ty.id(),
+        event.ty.id,
         |name| name.into(),
         "Event",
         crate_path,
@@ -74,9 +74,9 @@ pub fn generate_events(
             }
         }
     });
-    let event_type = type_gen.resolve_type_path(event.ty.id());
-    let event_ty = type_gen.resolve_type(event.ty.id());
-    let docs = event_ty.docs();
+    let event_type = type_gen.resolve_type_path(event.ty.id);
+    let event_ty = type_gen.resolve_type(event.ty.id);
+    let docs = event_ty.docs;
     let docs = should_gen_docs
         .then_some(quote! { #( #[doc = #docs ] )* })
         .unwrap_or_default();