README.md in embulk-output-elasticsearch-0.1.8 vs README.md in embulk-output-elasticsearch-0.2.0

@@ -7,30 +7,106 @@
 * **Resume supported**: no
 * **Cleanup supported**: no
 
 ## Configuration
 
+- **mode**: "insert" or "replace". See below(string, optional, default is insert)
 - **nodes**: list of nodes. nodes are pairs of host and port (list, required)
 - **cluster_name**: name of the cluster (string, default is "elasticsearch")
 - **index**: index name (string, required)
 - **index_type**: index type (string, required)
 - **id**: document id column (string, default is null)
 - **bulk_actions**: Sets when to flush a new bulk request based on the number of actions currently added. (int, default is 1000)
 - **bulk_size**: Sets when to flush a new bulk request based on the size of actions currently added. (long, default is 5242880)
 - **concurrent_requests**: concurrent_requests (int, default is 5)
 
+### Modes
+
+#### insert:
+
+default.
+This mode writes data to existing index.
+
+#### replace:
+
+1. Create new temporary index 
+2. Insert data into the new index
+3. replace the alias with the new index. If alias doesn't exists, plugin will create new alias.
+4. Delete existing (old) index if exists
+
+Index should not exists with the same name as the alias
+
+```yaml
+out:
+  type: elasticsearch
+  mode: replace
+  nodes:
+  - {host: localhost, port: 9300}
+  index: <alias name> # plugin generates index name like <index>_%Y%m%d-%H%M%S 
+  index_type: <index type>
+```
+
 ## Example
 
 ```yaml
 out:
   type: elasticsearch
+  mode: insert
   nodes:
   - {host: localhost, port: 9300}
   index: <index name>
   index_type: <index type>
 ```
 
 ## Build
 
 ```
-$ ./gradlew gem
+$ ./gradlew gem  # -t to watch change of files and rebuild continuously
 ```
+
+## Test
+
+```
+$ ./gradlew test  # -t to watch change of files and rebuild continuously
+```
+
+To run unit tests, we need to configure the following environment variables.
+
+When environment variables are not set, skip almost test cases.
+
+```
+ES_HOST
+ES_PORT(optional, if needed, default: 9300)
+ES_INDEX
+ES_INDEX_TYPE
+```
+
+If you're using Mac OS X El Capitan and GUI Applications(IDE), like as follows.
+```
+$ vi ~/Library/LaunchAgents/environment.plist
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>Label</key>
+  <string>my.startup</string>
+  <key>ProgramArguments</key>
+  <array>
+    <string>sh</string>
+    <string>-c</string>
+    <string>
+      launchctl setenv ES_HOST example.com
+      launchctl setenv ES_PORT 9300
+      launchctl setenv ES_INDEX embulk
+      launchctl setenv ES_INDEX_TYPE embulk
+    </string>
+  </array>
+  <key>RunAtLoad</key>
+  <true/>
+</dict>
+</plist>
+
+$ launchctl load ~/Library/LaunchAgents/environment.plist
+$ launchctl getenv ES_INDEX //try to get value.
+
+Then start your applications.
+```
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