add indexer latest block

res/indexer-queries.graphql

 query IdentityNameByPubkey($pubkey: String!) {
-	identity(where: {pubkey: {_eq: $pubkey}}) {
-		name
-	}
+  identity(where: { pubkey: { _eq: $pubkey } }) {
+    name
+  }
 }
 
 query IdentityPubkeyByName($name: String!) {
-	identity_by_pk(name: $name) {
-		pubkey
-	}
+  identity_by_pk(name: $name) {
+    pubkey
+  }
+}
+
+query LatestBlock {
+  parameters(where: { key: { _eq: "last_indexed_block_number" } }) {
+    value
+  }
 }

src/indexer.rs

-pub use graphql_client::{reqwest::post_graphql, GraphQLQuery};
+use graphql_client::reqwest::post_graphql;
+use graphql_client::GraphQLQuery;
 
-use anyhow::Result;
+use crate::*;
+
+// type used in parameters query
+#[allow(non_camel_case_types)]
+type jsonb = serde_json::Value;
 
 #[derive(GraphQLQuery)]
 #[graphql(
@@ -16,14 +21,21 @@ pub struct IdentityNameByPubkey;
 )]
 pub struct IdentityPubkeyByName;
 
-#[derive(Clone)]
+#[derive(GraphQLQuery)]
+#[graphql(
+	schema_path = "res/indexer-schema.json",
+	query_path = "res/indexer-queries.graphql"
+)]
+pub struct LatestBlock;
+
+#[derive(Clone, Debug)]
 pub struct Indexer {
 	pub gql_client: reqwest::Client,
 	pub gql_url: String,
 }
 
 impl Indexer {
-	pub async fn username_by_pubkey(&self, pubkey: &str) -> Result<Option<String>> {
+	pub async fn username_by_pubkey(&self, pubkey: &str) -> anyhow::Result<Option<String>> {
 		Ok(post_graphql::<IdentityNameByPubkey, _>(
 			&self.gql_client,
 			&self.gql_url,
@@ -36,7 +48,7 @@ impl Indexer {
 		.and_then(|data| data.identity.into_iter().next().map(|idty| idty.name)))
 	}
 
-	pub async fn pubkey_by_username(&self, username: &str) -> Result<Option<String>> {
+	pub async fn pubkey_by_username(&self, username: &str) -> anyhow::Result<Option<String>> {
 		Ok(post_graphql::<IdentityPubkeyByName, _>(
 			&self.gql_client,
 			self.gql_url.clone(),
@@ -48,4 +60,50 @@ impl Indexer {
 		.data
 		.and_then(|data| data.identity_by_pk.map(|idty| idty.pubkey)))
 	}
+
+	/// fetch latest block
+	pub async fn fetch_latest_block(&self) -> Result<u64, anyhow::Error> {
+		Ok(post_graphql::<LatestBlock, _>(
+			&self.gql_client,
+			self.gql_url.clone(),
+			latest_block::Variables {},
+		)
+		.await?
+		.data
+		.unwrap() // must have a data field
+		.parameters
+		.first()
+		.unwrap() // must have one and only one parameter matching request
+		.value
+		.clone()
+		.unwrap() // must have a value field
+		.as_u64()
+		.unwrap()) // must be a Number of blocks
+	}
+}
+
+#[derive(Clone, Default, Debug, clap::Parser)]
+pub enum IndexerSubcommand {
+	#[default]
+	/// Show indexer endpoint
+	ShowEndpoint,
+	/// Fetch latest indexed block
+	LatestBlock,
+}
+
+pub async fn handle_command(data: Data, command: IndexerSubcommand) -> anyhow::Result<()> {
+	let data = data.build_indexer()?;
+	match command {
+		IndexerSubcommand::ShowEndpoint => {
+			println!("indexer endpoint: {}", data.indexer().gql_url);
+		}
+		IndexerSubcommand::LatestBlock => {
+			println!(
+				"latest indexed block is: {}",
+				data.indexer().fetch_latest_block().await?
+			);
+		}
+	};
+
+	Ok(())
 }

src/main.rs

@@ -564,7 +564,7 @@ async fn main() -> Result<(), GcliError> {
 		.await
 		.unwrap(),
 		Subcommand::RuntimeInfo => commands::runtime::runtime_info(data).await,
-		Subcommand::Indexer(subcommand) => indexer::handle_command(data, subcommand)?,
+		Subcommand::Indexer(subcommand) => indexer::handle_command(data, subcommand).await?,
 	}
 
 	Ok(())