Now SCRIPT FLUSH, etc. does not makes consequent executions fail

Author: javajefe

README.md

@@ -7,6 +7,9 @@ However, some latest Redis APIs are not implemented (for example, Redis Streams
 This small library tries to implement some missing functions. The approach is very simple: every command is implemented as Lua script. BWT it would be obviously better to get native support (at least of stream commands) in Jedis.
 
 ### Release notes
+##### v 0.0.2
+- Now `SCRIPT FLUSH`, etc. does not makes consequent executions fail.
+
 ##### v 0.0.1
 - Implemented batch `XADD` command.
 - Implemented `XDEL` command.

build.gradle

@@ -1,5 +1,5 @@
 group 'tech.javajefe'
-version '0.0.1'
+version '0.0.2'
 
 apply plugin: 'groovy'
 apply plugin: 'java'

src/main/java/tech/javajefe/redis/jedis/extensions/RedisExtensions.java

@@ -4,9 +4,11 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import redis.clients.jedis.commands.ScriptingCommands;
+import redis.clients.jedis.exceptions.JedisNoScriptException;
 
 import java.io.IOException;
 import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 
 /**
@@ -15,36 +17,60 @@
 public class RedisExtensions {
 
     private static final Logger log = LoggerFactory.getLogger(RedisExtensions.class);
-    private enum SCRIPTS {
 
-        executeArbitraryCommand("/lua/executeArbitraryCommand.lua"),
-        batchXADD("/lua/batchXADD.lua");
-
-        private String path;
-
-        SCRIPTS(String path) {
-            this.path = path;
-        }
-
-        String getPath() {
-            return this.path;
-        }
-    }
     private final Gson gson;
     private final ScriptingCommands client;
-    private final Map<SCRIPTS, String> loadedScriptIds;
+    private final Map<Scripts, String> loadedScriptIds;
 
     public RedisExtensions(ScriptingCommands client) throws IOException {
         this.gson = new Gson();
         this.client = client;
-        Map<SCRIPTS, String> scripts = new HashMap<>();
-        for (SCRIPTS scriptMeta: SCRIPTS.values()) {
-            String lua = Utils.loadResource(scriptMeta.getPath());
-            String sha = client.scriptLoad(lua);
-            log.debug("Loaded script {} with sha marker {}", sha);
-            scripts.put(scriptMeta, sha);
+        Map<Scripts, String> scripts = new ConcurrentHashMap<>();
+        for (Scripts scriptMeta: Scripts.values()) {
+            scripts.put(scriptMeta, loadScript(scriptMeta));
+        }
+        this.loadedScriptIds = scripts;
+    }
+
+    public Object executeArbitraryCommand(String...params) {
+        return executeArbitraryCommand(Arrays.asList(params));
+    }
+
+    private Object executeArbitraryCommand(List<String> params) {
+        return evalShaWithRetry(Scripts.executeArbitraryCommand, Collections.EMPTY_LIST, params);
+    }
+
+    private String loadScript(Scripts scriptMeta) throws IOException {
+        String lua = Utils.loadResource(scriptMeta.getPath());
+        String sha = client.scriptLoad(lua);
+        log.debug("Loaded script {} with sha marker {}", scriptMeta.getPath(), sha);
+        return sha;
+    }
+
+    private Object evalShaWithRetry(Scripts script, List<String> keys, List<String> args) {
+        return evalShaWithRetry(script, keys, args, true);
+    }
+
+    private Object evalShaWithRetry(Scripts script, List<String> keys, List<String> args, boolean firstAttempt) {
+        Object result = null;
+        String sha = loadedScriptIds.get(script);
+        try {
+            result = client.evalsha(sha, keys, args);
+        } catch (JedisNoScriptException ex) {
+            if (firstAttempt) {
+                log.warn("No script {} with sha marker {}. Trying to reload.", script.getPath(), sha);
+                try {
+                    String newSha = loadScript(script);
+                    loadedScriptIds.put(script, newSha);
+                    result = evalShaWithRetry(script, keys, args, false);
+                } catch (IOException ioex) {
+                    throw ex;
+                }
+            } else {
+                throw ex;
+            }
         }
-        this.loadedScriptIds = Collections.unmodifiableMap(scripts);
+        return result;
     }
 
     public List<StreamMessageId> batchXADD(String key, List<Map<String, String>> messages) {
@@ -57,24 +83,14 @@ public List<StreamMessageId> batchXADD(String key, List<Map<String, String>> mes
         if (messages.stream().flatMap(m -> m.values().stream()).anyMatch(v -> v == null)) {
             throw new IllegalArgumentException("null values are disallowed");
         }
-        String sha = loadedScriptIds.get(SCRIPTS.batchXADD);
         List<String> argv = messages.stream()
                 .map(m -> gson.toJson(m))
                 .collect(Collectors.toList());
-        List<String> ids = (List<String>) client.evalsha(sha, Collections.singletonList(key), argv);
+        List<String> ids = (List<String>) evalShaWithRetry(Scripts.batchXADD,
+                Collections.singletonList(key), argv);
         return ids.stream().map(StreamMessageId::from).collect(Collectors.toList());
     }
 
-    public Object executeArbitraryCommand(String...params) {
-        String sha = loadedScriptIds.get(SCRIPTS.executeArbitraryCommand);
-        return client.evalsha(sha, 0, params);
-    }
-
-    public Object executeArbitraryCommand(List<String> params) {
-        String sha = loadedScriptIds.get(SCRIPTS.executeArbitraryCommand);
-        return client.evalsha(sha, Collections.EMPTY_LIST, params);
-    }
-
     public long XDEL(String key, List<StreamMessageId> ids) {
         // TODO
         List<String> params = ids.stream()

src/main/java/tech/javajefe/redis/jedis/extensions/Scripts.java

@@ -0,0 +1,20 @@
+package tech.javajefe.redis.jedis.extensions;
+
+/**
+ * Created by Alexander Bukarev on 07.03.2019.
+ */
+enum Scripts {
+
+    executeArbitraryCommand("/lua/executeArbitraryCommand.lua"),
+    batchXADD("/lua/batchXADD.lua");
+
+    private String path;
+
+    Scripts(String path) {
+        this.path = path;
+    }
+
+    String getPath() {
+        return this.path;
+    }
+}

src/test/groovy/tech/javajefe/redis/jedis/extensions/RedisExtensionsTests.groovy

@@ -34,6 +34,17 @@ class RedisExtensionsTests extends Specification {
         jedis.close()
     }
 
+    def "All commands stay operatable after FLUSHALL / FLUSHDB / SCRIPT FLUSH / restart / etc."() {
+        when:
+            redisExtensions.batchXADD(streamName, [[i: 1 as String]])
+            jedis.scriptFlush()
+            redisExtensions.batchXADD(streamName, [[i: 2 as String]])
+            def streamSize = redisExtensions.XLEN(streamName)
+        then:
+            notThrown(Throwable)
+            streamSize == 2
+    }
+
     def "Empty key is not allowed in Batch XADD"() {
         when:
             redisExtensions.batchXADD('', [[k: 'v']])