feat(abigen): add MultiAbigen to generate multiple contract bindings (#724)

* feat(abigen): add MultiAbigen to generate multiple contract bindings

* docs: more docs

* chore: update changelog

* rustmft

* chore: add json extension check

CHANGELOG.md

@@ -23,6 +23,8 @@
 
 ## ethers-contract-abigen
 
+- Add `MultiAbigen` to generate a series of contract bindings that can be kept in the repo
+  [#724](https://github.com/gakonst/ethers-rs/pull/724).
 - Add provided `event_derives` to call and event enums as well
   [#721](https://github.com/gakonst/ethers-rs/pull/721).
 - Implement snowtrace and polygonscan on par with the etherscan integration

Cargo.lock

@@ -1109,6 +1109,7 @@ dependencies = [
  "serde",
  "serde_json",
  "syn",
+ "tempfile",
  "url",
 ]
 

ethers-contract/ethers-contract-abigen/Cargo.toml

@@ -38,3 +38,6 @@ rustdoc-args = ["--cfg", "docsrs"]
 default = ["reqwest", "rustls"]
 openssl = ["reqwest/native-tls"]
 rustls = ["reqwest/rustls-tls"]
+
+[dev-dependencies]
+tempfile = "3.2.0"

ethers-contract/ethers-contract-abigen/src/contract.rs

@@ -154,27 +154,8 @@ impl Context {
         // get the actual ABI string
         let abi_str =
             args.abi_source.get().map_err(|e| anyhow!("failed to get ABI JSON: {}", e))?;
-        let mut abi_parser = AbiParser::default();
 
-        let (abi, human_readable): (Abi, _) = if let Ok(abi) = abi_parser.parse_str(&abi_str) {
+        let (abi, human_readable, abi_parser) = parse_abi(&abi_str)?;
-            (abi, true)
-        } else {
-            // a best-effort coercion of an ABI or an artifact JSON into an artifact JSON.
-            let json_abi_str = if abi_str.trim().starts_with('[') {
-                format!(r#"{{"abi":{}}}"#, abi_str.trim())
-            } else {
-                abi_str.clone()
-            };
-
-            #[derive(Deserialize)]
-            struct Contract {
-                abi: Abi,
-            }
-
-            let contract = serde_json::from_str::<Contract>(&json_abi_str)?;
-
-            (contract.abi, false)
-        };
 
         // try to extract all the solidity structs from the normal JSON ABI
         // we need to parse the json abi again because we need the internalType fields which are
@@ -251,3 +232,25 @@ impl Context {
         &mut self.internal_structs
     }
 }
+
+/// Parse the abi via `Source::parse` and return if the abi defined as human readable
+fn parse_abi(abi_str: &str) -> Result<(Abi, bool, AbiParser)> {
+    let mut abi_parser = AbiParser::default();
+    let res = if let Ok(abi) = abi_parser.parse_str(abi_str) {
+        (abi, true, abi_parser)
+    } else {
+        #[derive(Deserialize)]
+        struct Contract {
+            abi: Abi,
+        }
+        // a best-effort coercion of an ABI or an artifact JSON into an artifact JSON.
+        let contract: Contract = if abi_str.trim_start().starts_with('[') {
+            serde_json::from_str(&format!(r#"{{"abi":{}}}"#, abi_str.trim()))?
+        } else {
+            serde_json::from_str::<Contract>(abi_str)?
+        };
+
+        (contract.abi, false, abi_parser)
+    };
+    Ok(res)
+}

ethers-contract/ethers-contract-abigen/src/lib.rs

@@ -24,8 +24,14 @@ pub use source::Source;
 pub use util::parse_address;
 
 use anyhow::Result;
+use inflector::Inflector;
 use proc_macro2::TokenStream;
-use std::{collections::HashMap, fs::File, io::Write, path::Path};
+use std::{
+    collections::HashMap,
+    fs::{self, File},
+    io::Write,
+    path::Path,
+};
 
 /// Builder struct for generating type-safe bindings from a contract's ABI
 ///
@@ -44,6 +50,7 @@ use std::{collections::HashMap, fs::File, io::Write, path::Path};
 /// Abigen::new("ERC20Token", "./abi.json")?.generate()?.write_to_file("token.rs")?;
 /// # Ok(())
 /// # }
+#[derive(Debug, Clone)]
 pub struct Abigen {
     /// The source of the ABI JSON for the contract whose bindings
     /// are being generated.
@@ -180,3 +187,286 @@ impl ContractBindings {
         self.tokens
     }
 }
+
+/// Generates bindings for a series of contracts
+///
+/// This type can be used to generate multiple `ContractBindings` and put them all in a single rust
+/// module, (eg. a `contracts` directory).
+///
+/// This can be used to
+/// 1) write all bindings directly into a new directory in the project's source directory, so that
+/// it is included in the repository. 2) write all bindings to the value of cargo's `OUT_DIR` in a
+/// build script and import the bindings as `include!(concat!(env!("OUT_DIR"), "/mod.rs"));`.
+///
+/// However, the main purpose of this generator is to create bindings for option `1)` and write all
+/// contracts to some `contracts`  module in `src`, like `src/contracts/mod.rs` __once__ via a build
+/// script or a test. After that it's recommend to remove the build script and replace it with an
+/// integration test (See `MultiAbigen::ensure_consistent_bindings`) that fails if the generated
+/// code is out of date. This has several advantages:
+///
+///   * No need for downstream users to compile the build script
+///   * No need for downstream users to run the whole `abigen!` generation steps
+///   * The generated code is more usable in an IDE
+///   * CI will fail if the generated code is out of date (if `abigen!` or the contract's ABI itself
+///     changed)
+///
+/// See `MultiAbigen::ensure_consistent_bindings` for the recommended way to set this up to generate
+/// the bindings once via a test and then use the test to ensure consistency.
+#[derive(Debug, Clone)]
+pub struct MultiAbigen {
+    /// whether to write all contracts in a single file instead of separated modules
+    single_file: bool,
+
+    abigens: Vec<Abigen>,
+}
+
+impl MultiAbigen {
+    /// Create a new instance from a series of already resolved `Abigen`
+    pub fn from_abigen(abis: impl IntoIterator<Item = Abigen>) -> Self {
+        Self {
+            single_file: false,
+            abigens: abis.into_iter().map(|abi| abi.rustfmt(true)).collect(),
+        }
+    }
+
+    /// Create a new instance from a series (`contract name`, `abi_source`)
+    ///
+    /// See `Abigen::new`
+    pub fn new<I, Name, Source>(abis: I) -> Result<Self>
+    where
+        I: IntoIterator<Item = (Name, Source)>,
+        Name: AsRef<str>,
+        Source: AsRef<str>,
+    {
+        let abis = abis
+            .into_iter()
+            .map(|(contract_name, abi_source)| Abigen::new(contract_name.as_ref(), abi_source))
+            .collect::<Result<Vec<_>>>()?;
+
+        Ok(Self::from_abigen(abis))
+    }
+
+    /// Reads all json files contained in the given `dir` and use the file name for the name of the
+    /// `ContractBindings`.
+    /// This is equivalent to calling `MultiAbigen::new` with all the json files and their filename.
+    ///
+    /// # Example
+    ///
+    /// ```text
+    /// abi
+    /// ├── ERC20.json
+    /// ├── Contract1.json
+    /// ├── Contract2.json
+    /// ...
+    /// ```
+    ///
+    /// ```no_run
+    /// # use ethers_contract_abigen::MultiAbigen;
+    /// let gen = MultiAbigen::from_json_files("./abi").unwrap();
+    /// ```
+    pub fn from_json_files(dir: impl AsRef<Path>) -> Result<Self> {
+        let mut abis = Vec::new();
+        for file in fs::read_dir(dir)?.into_iter().filter_map(std::io::Result::ok).filter(|p| {
+            p.path().is_file() && p.path().extension().and_then(|ext| ext.to_str()) == Some("json")
+        }) {
+            let file: fs::DirEntry = file;
+            if let Some(file_name) = file.path().file_stem().and_then(|s| s.to_str()) {
+                let content = fs::read_to_string(file.path())?;
+                abis.push((file_name.to_string(), content));
+            }
+        }
+        Self::new(abis)
+    }
+
+    /// Write all bindings into a single rust file instead of separate modules
+    #[must_use]
+    pub fn single_file(mut self) -> Self {
+        self.single_file = true;
+        self
+    }
+
+    /// Generates all the bindings and writes them to the given module
+    ///
+    /// # Example
+    ///
+    /// Read all json abi files from the `./abi` directory
+    /// ```text
+    /// abi
+    /// ├── ERC20.json
+    /// ├── Contract1.json
+    /// ├── Contract2.json
+    /// ...
+    /// ```
+    ///
+    /// and write them to the `./src/contracts` location as
+    ///
+    /// ```text
+    /// src/contracts
+    /// ├── mod.rs
+    /// ├── er20.rs
+    /// ├── contract1.rs
+    /// ├── contract2.rs
+    /// ...
+    /// ```
+    ///
+    /// ```no_run
+    /// # use ethers_contract_abigen::MultiAbigen;
+    /// let gen = MultiAbigen::from_json_files("./abi").unwrap();
+    /// gen.write_to_module("./src/contracts").unwrap();
+    /// ```
+    pub fn write_to_module(self, module: impl AsRef<Path>) -> Result<()> {
+        let module = module.as_ref();
+        fs::create_dir_all(module)?;
+
+        let mut contracts_mod =
+            b"/// This module contains all the autogenerated abigen! contract bindings\n".to_vec();
+
+        let mut modules = Vec::new();
+        for abi in self.abigens {
+            let name = abi.contract_name.to_snake_case();
+            let bindings = abi.generate()?;
+            if self.single_file {
+                // append to the mod file
+                bindings.write(&mut contracts_mod)?;
+            } else {
+                // create a contract rust file
+                let output = module.join(format!("{}.rs", name));
+                bindings.write_to_file(output)?;
+                modules.push(format!("pub mod {};", name));
+            }
+        }
+
+        if !modules.is_empty() {
+            modules.sort();
+            write!(contracts_mod, "{}", modules.join("\n"))?;
+        }
+
+        // write the mod file
+        fs::write(module.join("mod.rs"), contracts_mod)?;
+
+        Ok(())
+    }
+
+    /// This ensures that the already generated contract bindings match the output of a fresh new
+    /// run. Run this in a rust test, to get notified in CI if the newly generated bindings
+    /// deviate from the already generated ones, and it's time to generate them again. This could
+    /// happen if the ABI of a contract or the output that `ethers` generates changed.
+    ///
+    /// So if this functions is run within a test during CI and fails, then it's time to update all
+    /// bindings.
+    ///
+    /// Returns `true` if the freshly generated bindings match with the existing bindings, `false`
+    /// otherwise
+    ///
+    /// # Example
+    ///
+    /// Check that the generated files are up to date
+    ///
+    /// ```no_run
+    /// # use ethers_contract_abigen::MultiAbigen;
+    /// #[test]
+    /// fn generated_bindings_are_fresh() {
+    ///  let project_root = std::path::Path::new(&env!("CARGO_MANIFEST_DIR"));
+    ///  let abi_dir = project_root.join("abi");
+    ///  let gen = MultiAbigen::from_json_files(&abi_dir).unwrap();
+    ///  assert!(gen.ensure_consistent_bindings(project_root.join("src/contracts")));
+    /// }
+    ///
+    /// gen.write_to_module("./src/contracts").unwrap();
+    /// ```
+    #[cfg(test)]
+    pub fn ensure_consistent_bindings(self, module: impl AsRef<Path>) -> bool {
+        let module = module.as_ref();
+        let dir = tempfile::tempdir().expect("Failed to create temp dir");
+        let temp_module = dir.path().join("contracts");
+        self.write_to_module(&temp_module).expect("Failed to generate bindings");
+
+        for file in fs::read_dir(&temp_module).unwrap() {
+            let fresh_file = file.unwrap();
+            let fresh_file_path = fresh_file.path();
+            let file_name = fresh_file_path.file_name().and_then(|p| p.to_str()).unwrap();
+            assert!(file_name.ends_with(".rs"), "Expected rust file");
+
+            let existing_bindings_file = module.join(file_name);
+
+            if !existing_bindings_file.is_file() {
+                // file does not already exist
+                return false
+            }
+
+            // read the existing file
+            let existing_contract_bindings = fs::read_to_string(existing_bindings_file).unwrap();
+
+            let fresh_bindings = fs::read_to_string(fresh_file.path()).unwrap();
+
+            if existing_contract_bindings != fresh_bindings {
+                return false
+            }
+        }
+        true
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn can_generate_multi_abi() {
+        let crate_root = std::path::Path::new(&env!("CARGO_MANIFEST_DIR"));
+
+        let tempdir = tempfile::tempdir().unwrap();
+        let mod_root = tempdir.path().join("contracts");
+
+        let console = Abigen::new(
+            "Console",
+            crate_root.join("../tests/solidity-contracts/console.json").display().to_string(),
+        )
+        .unwrap();
+
+        let simple_storage = Abigen::new(
+            "SimpleStorage",
+            crate_root
+                .join("../tests/solidity-contracts/simplestorage_abi.json")
+                .display()
+                .to_string(),
+        )
+        .unwrap();
+
+        let human_readable = Abigen::new(
+            "HrContract",
+            r#"[
+        struct Foo { uint256 x; }
+        function foo(Foo memory x)
+        function bar(uint256 x, uint256 y, address addr)
+        yeet(uint256,uint256,address)
+    ]"#,
+        )
+        .unwrap();
+
+        let mut multi_gen = MultiAbigen::from_abigen([console, simple_storage, human_readable]);
+
+        multi_gen.clone().write_to_module(&mod_root).unwrap();
+        assert!(multi_gen.clone().ensure_consistent_bindings(&mod_root));
+
+        // add another contract
+        multi_gen.abigens.push(
+            Abigen::new(
+                "AdditionalContract",
+                r#"[
+        getValue() (uint256)
+        getValue(uint256 otherValue) (uint256)
+        getValue(uint256 otherValue, address addr) (uint256)
+    ]"#,
+            )
+            .unwrap(),
+        );
+
+        // ensure inconsistent bindings are detected
+        assert!(!multi_gen.clone().ensure_consistent_bindings(&mod_root));
+
+        // update with new contract
+        multi_gen.clone().write_to_module(&mod_root).unwrap();
+        assert!(multi_gen.clone().ensure_consistent_bindings(&mod_root));
+    }
+}