DLT 本地log功能配置

dlt本地log

需要指定APP NAME和CONTEX NAME才能儲存對應的log。

1、操作過程:
在dlt.conf中開啟本地log的配置項：

然後再在OfflineLogstorageDirPath路徑下建立本地log規則檔案：dlt_logstorage.conf
在檔案中寫入過濾規則：

再啟動dlt-daemon -c /etc/dlt.conf -d，這樣就可以讓dlt針對LOG 這個app中以TEST為名的ctx的log（log等級大於DLT_LOG_WARN）都儲存在/opt/test下的dlt檔案中。

這個檔案應該可以用dlt-veiwer開啟。

2、dlt關於本地log的幫助可以在 doc/dlt_offline_logstorage.md 檔案中找到。

3、幫助文件中的測試方法：

## Testing DLT Offline Logstorage

The following procedure can be used to test Offline Logstorage:

- Enable OfflineLogstorage by setting OfflineLogstorageMaxDevices = 1 in dlt.conf
- Start dlt-daemon
- The default search path of logstorage is: /tmp/dltlogs/dltlogsdevX   where X is a number in the range [1..OfflineLogstorageMaxDevices]

- Create the device folder

    ```
  $ mkdir -p /var/dltlog
    ```

- Create the configuration file "dlt\_logstorage.conf" in this folder   and define filter configuration(s):

    ```
    [FILTER1]   
    LogAppName=LOG   
    ContextName=TEST   
    LogLevel=DLT_LOG_WARN   
    File=example   
    FileSize=50000   
    NOFiles=5   
    ```

- Trigger dlt-daemon to use a new device

    ```
    $ dlt-logstorage-ctrl -c 1 -p /var/dltlog
    ```

- Start dlt-example-user

    ```
    $ dlt-example-user Hello123
    ```

- After execution, a log file is created in /var/dltlogs
- e.g. example\_001\_20150512\_133344.dlt

- To check the content of the file open it with dlt-convert or DLT Viewer.

## Logstorage Ring Buffer Implementation