Subscribe to Runtime upgrades for proper extrinsic construction (#513)

* subxt: Add subscription to runtime upgrades

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Synchronize and expose inner `RuntimeVersion` of the `Client`

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* examples: Add runtime update example

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Expose `RuntimeVersion` as locked

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Expose `Metadata` as locked

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt/storage: Use locked metadata

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Use parking lot RwLock variant for locked metadata

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Utilize locked metadata variant

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt/transaction: Use locked metadata variant

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Update subxt to use locked version of the Metadata

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Add runtime update client wrapper

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* examples: Modify runtime update example

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Fix clippy

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Fix cargo check

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Keep consistency with cargo check fix

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Remove unnecessary Arc

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Remove MetadataInner and use parking_lot::RwLock

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Update polkadot.rs

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Update polkadot.rs generation comment

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Switch to async::Mutex

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Block executor while decoding dynamic events

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Use async API to handle async locking

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Remove unused dependencies

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Update examples and integration-tests

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Fix test deadlock

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Revert back to sync lock

Revert "Fix test deadlock"

This reverts commit 4a79933df23e81573611cb14be6c5b5b2b56d4df.

Revert "Update examples and integration-tests"

This reverts commit 5423f6eb4131582909d5a4ca70adff75e27cdd0e.

Revert "Remove unused dependencies"

This reverts commit e8ecbabb5b01a7ba4ae83b8bde36295a3f64daf7.

Revert "codegen: Use async API to handle async locking"

This reverts commit ced4646541c431adcb973369b1061b7b3cbfaae1.

Revert "subxt: Block executor while decoding dynamic events"

This reverts commit 8b3ba4a5eabb29f77ac1ca671450956fc479a33d.

Revert "subxt: Switch to async::Mutex"

This reverts commit f5bde9b79394a6bf61b6b9daefc36ceaa84b82be.

* subxt: Perform RuntimeVersion update before fetching metadata

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Reintroduce MetadataInner

* Use parking lot instead of std::RwLock

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt: Reduce lock metadata time when decoding events

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* codegen: Update `validate_metdata` locking pattern

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* subxt/examples: Update polkadot download link

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* tests: Wrap metadata in a helper function

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Update examples/examples/subscribe_runtime_updates.rs

Co-authored-by: James Wilson <james@jsdw.me>

* subxt/updates: Update runtime if version is different

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

Co-authored-by: James Wilson <james@jsdw.me>

codegen/src/api/mod.rs

@@ -312,7 +312,12 @@ impl RuntimeGenerator {
                     X: ::subxt::extrinsic::ExtrinsicParams<T>,
                 {
                     pub fn validate_metadata(&'a self) -> Result<(), ::subxt::MetadataError> {
-                        if self.client.metadata().metadata_hash(&PALLETS) != [ #(#metadata_hash,)* ] {
+                        let runtime_metadata_hash = {
+                            let locked_metadata = self.client.metadata();
+                            let metadata = locked_metadata.read();
+                            metadata.metadata_hash(&PALLETS)
+                        };
+                        if runtime_metadata_hash != [ #(#metadata_hash,)* ] {
                             Err(::subxt::MetadataError::IncompatibleMetadata)
                         } else {
                             Ok(())
@@ -341,7 +346,7 @@ impl RuntimeGenerator {
                 }
 
                 impl <'a, T: ::subxt::Config> EventsApi<'a, T> {
-                    pub async fn at(&self, block_hash: T::Hash) -> Result<::subxt::events::Events<'a, T, Event>, ::subxt::BasicError> {
+                    pub async fn at(&self, block_hash: T::Hash) -> Result<::subxt::events::Events<T, Event>, ::subxt::BasicError> {
                         ::subxt::events::at::<T, Event>(self.client, block_hash).await
                     }