build script

Author: mraszyk

rs/pocket_ic_server/build.rs

@@ -71,4 +71,22 @@ struct Dashboard<'a> {{
             );
         }
     }
+
+    // The environment variable `MAINNET_ROUTING_TABLE` pointing to a file (storing the mainnet routing table) is needed
+    // for the PocketIC server to compile. There are two flows to support:
+    // - code validation using `cargo`: we create a dummy file and point `MAINNET_ROUTING_TABLE` to that file for code validation to succeed;
+    // - building the PocketIC server using `bazel`: `bazel` always sets `MAINNET_ROUTING_TABLE` to an actual file storing the mainnet routing table
+    //   (built separately) and thus we don't override `MAINNET_ROUTING_TABLE` if already set.
+    let mainnet_routing_table_var_name = "MAINNET_ROUTING_TABLE".to_string();
+    if std::env::var(&mainnet_routing_table_var_name).is_err() {
+        let mainnet_routing_table_file_name = "mainnet_routing_table.json";
+        let mainnet_routing_table_file_path =
+            PathBuf::from(std::env::var("OUT_DIR").unwrap()).join(mainnet_routing_table_file_name);
+        File::create(&mainnet_routing_table_file_path).unwrap();
+        println!(
+            "cargo:rustc-env={}={}",
+            mainnet_routing_table_var_name,
+            mainnet_routing_table_file_path.display()
+        );
+    }
 }