Revert "node: Turn --readonly-db flag into an env var"

This reverts commit 258cd72.

Author: leoyvens

node/src/main.rs

@@ -52,14 +52,6 @@ lazy_static! {
         .map(|s| u64::from_str(&s)
              .unwrap_or_else(|_| panic!("failed to parse env var ETHEREUM_ANCESTOR_COUNT")))
         .unwrap_or(50);
-
-    // Run against a read-only database. This turns off a few things:
-    // - Chain head listeners
-    // - Store events
-    // - Subscriptions and the WebSocket server
-    // - The JSON-RPC admin server
-    static ref EXPERIMENTAL_READONLY_DB: bool = env::var("GRAPH_EXPERIMENTAL_READONLY_DB")
-        .ok().is_some();
 }
 
 git_testament!(TESTAMENT);
@@ -297,6 +289,12 @@ async fn main() {
                 .value_name("URL")
                 .help("HTTP endpoint for 3box profiles"),
         )
+        .arg(
+            Arg::with_name("readonly-db")
+                .takes_value(false)
+                .long("readonly-db")
+                .help("Run against a readonly db (no subscriptions etc.)"),
+        )
         .get_matches();
 
     // Set up logger
@@ -534,7 +532,9 @@ async fn main() {
         connection_pool_registry,
     );
 
-    let chain_head_update_listener = if *EXPERIMENTAL_READONLY_DB {
+    let readonly_db = matches.is_present("readonly-db");
+
+    let chain_head_update_listener = if readonly_db {
         None
     } else {
         Some(Arc::new(PostgresChainHeadUpdateListener::new(
@@ -544,7 +544,7 @@ async fn main() {
         )))
     };
 
-    let subscriptions = if *EXPERIMENTAL_READONLY_DB {
+    let subscriptions = if readonly_db {
         None
     } else {
         Some(Arc::new(SubscriptionManager::new(
@@ -616,7 +616,7 @@ async fn main() {
 
             // Disable the subscriptions server when running against a read-only
             // database
-            if !*EXPERIMENTAL_READONLY_DB {
+            if !readonly_db {
                 let subscription_server = GraphQLSubscriptionServer::new(
                     &logger,
                     graphql_runner.clone(),
@@ -634,7 +634,7 @@ async fn main() {
                 node_id.clone(),
             );
 
-            if !*EXPERIMENTAL_READONLY_DB {
+            if !readonly_db {
                 // Spawn Ethereum network indexers for all networks that are to be indexed
                 if let Some(network_subgraphs) = matches.values_of("network-subgraphs") {
                     network_subgraphs