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Logstorage is a mechanism to store DLT logs on the target system or an external device (e.g. USB stick) connected to the target. It can be seen as an improvement of the Offline Trace functionality which is already part of DLT.
Logstorage provides the following features:
General configuration is done inside dlt.conf. The following configuration options exist:
##############################################################################
# Offline logstorage #
##############################################################################
# Store DLT log messages, if not set offline logstorage is off (Default: off)
# Maximum devices to be used as offline logstorage devices
# OfflineLogstorageMaxDevices = 1
# Path to store DLT offline log storage messages (Default: off)
# OfflineLogstorageDirPath = /opt
# File options
# Appends timestamp in log file name, Disable by setting to 0 (Default: 1)
# OfflineLogstorageTimestamp = 0
# Appends delimiter in log file name, allowed punctutations only (Default: _)
# OfflineLogstorageDelimiter = _
# Wrap around value for log file count in file name (Default: UINT_MAX)
# OfflineLogstorageMaxCounter = 999
# Don't append counter for NOFiles=1 (Default: 0)
# OfflineLogstorageOptionalIndex = 1
# Maximal used memory for Logstorage Cache in KB (Default: 30000 KB)
# OfflineLogstorageCacheSize = 30000
For DLT daemon to store logs the configuration file named “dlt_logstorage.conf” should be present in external storage or internal storage device (= given path in the file system).
[Filter<unique number>] # filter configration name
LogAppName=<APID> # Name of application to store logs from. Multiple applications can be separated by "," and ".*" denotes all applications
ContextName=<CTID> # Name or names of contexts to store logs from. Multiple contexts can be separated by "," and ".*" denotes all contexts of the application
LogLevel=<Log level> # Define log level, e.g. DLT_LOG_INFO or DLT_LOG_FATAL
File=<file name> # Base name of the created files that containing the logs, e.g. "example". For further file naming scheme configurations see man dlt.conf
FileSize=<file size in bytes> # Maximum file size in bytes
NOFiles=<number of files> # Number of created files before oldest is deleted and a new one is created
SyncBehavior=<strategy> # Specify sync strategy. Default: Sync'ed after every message. See Logstorage Ringbuffer Implementation below.
EcuID=<ECUid> # Specify ECU identifier
SpecificSize=<spec size in bytes> # Store logs in storage devices after specific size is reached.
GzipCompression=<ON/OFF> # Write the logfiles with gzip compression.
OverwriteBehavior=<strategy> # Specify overwrite strategy. Default: Delete oldest file and continue. See Logstorage Ringbuffer Implementation below.
DisableNetwork=<ON/OFF> # Specify if the message shall be routed to network client.
The Parameters “SyncBehavior”, “GzipCompression”, “OverwriteBehavior”, “DisableNetwork”, “EcuID” and “SpecificSize” are optional - all others are mandatory.
If both of the parameter “LogAppName” and “ContextName” are set to wildcard or not present in the configuration file, “EcuID” must be specified.
A typical configuration file may look like:
[FILTER1]
LogAppName=APP1
ContextName=CON1,CON2
LogLevel=DLT_LOG_INFO
File=App
FileSize=10000
NOFiles=10
[FILTER2]
LogAppName=TEST
ContextName=.*
LogLevel=DLT_LOG_ERROR
File=Test
FileSize=250000
NOFiles=5
EcuID=ECU1
SyncBehavior=ON_SPECIFIC_SIZE
SpecificSize=5000
GzipCompression=on
[FILTER3]
LogAppName=TEST
ContextName=.*
LogLevel=DLT_LOG_ERROR
File=Test
FileSize=250000
NOFiles=5
SyncBehavior=ON_FILE_SIZE,ON_DEMAND
EcuID=ECU1
[FILTER4]
LogAppName=APP2
ContextName=.*
LogLevel=DLT_LOG_INFO
File=App2
FileSize=10000
NOFiles=5
SyncBehavior=ON_FILE_SIZE
EcuID=ECU1
OverwriteBehavior=DISCARD_NEW
DisableNetwork=ON
In case of Non-Verbose mode, following filters should be used.
[NON-VERBOSE-STORAGE-FILTER<unique number>] # filter configuration name for a Non-Verbose passive node
EcuID=<ECUid> # Specify ECU identifier
File=<file name> # Base name of the created files that containing the logs, e.g. "example". For further file naming scheme configurations see man dlt.conf
FileSize=<file size in bytes> # Maximum file size in bytes
NOFiles=<number of files> # Number of created files before oldest is deleted and a new one is created
GzipCompression=on # Compress the log files
[NON-VERBOSE-LOGLEVEL-CTRL<unique number>] # filter configuration name to control log level of Non-Verbose applications
LogAppName=<APID> # Name of application (wildcard allowed)
ContextName=<CTID> # Name of context (wildcard allowed)
LogLevel=<Log level> # Define log level, e.g. DLT_LOG_INFO or DLT_LOG_FATAL
EcuID=<ECUid> # Specify ECU identifier
A typical configuration file may look like:
[NON-VERBOSE-STORAGE-FILTER1]
EcuID=PASV
File=scc
FileSize=50000
NOFiles=5
[NON-VERBOSE-LOGLEVEL-CTRL1]
LogAppName=LOG
ContextName=TEST
LogLevel=DLT_LOG_DEBUG
EcuID=PASV
[NON-VERBOSE-LOGLEVEL-CTRL2]
LogAppName=.*
ContextName=.*
LogLevel=DLT_LOG_WARN
EcuID=PASV
Enable OfflineLogstorage by setting OfflineLogstorageMaxDevices = 1
in
dlt.conf. Be aware that the performance of DLT may drop if multiple Logstorage
devices are used; the performance depends on the write speed of the used device,
too.
Create the device folder:
mkdir -p /var/dltlogs
Create a configuration file and store it on into that folder or mount an external device containing a configuration file.
Start the DLT Daemon. This is not necessary if the DLT Daemon was started already with Offline Logstorage enabled.
Trigger DLT Daemon to use the new logstorage device:
dlt-logstorage-ctrl -c 1 -p /var/dltlogs
Afterwards, logs that match the filter configuration are stored onto the Logstorage device.
dlt-logstorage-ctrl -c 0 -p /var/dltlogs
The configured logstorage device is disconnected from the DLT Daemon.
Usage: dlt-logstorage-ctrl [options]
Send a trigger to DLT daemon to connect/disconnect a certain logstorage device
Options:
-c Connection type: connect = 1, disconnect = 0
-d[prop] Run as daemon: prop = use proprietary handler
'prop' may be replaced by any meaningful word
-e Set ECU ID (Default: ECU1)
-h Usage
-p Mount point path
-s Sync Logstorage cache
-t Specify connection timeout (Default: 10s)
-S Send message with serial header (Default: Without serial header)
-R Enable resync serial header
-v Set verbose flag (Default:0)
The following procedure can be used to test Offline Logstorage:
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
Example sequence can be found under tests/component/logstorage_one_file
and tests/component/logstorage_multi_file
.
The DLT Logstorage is mainly used to store a configurable set of logs on an external mass storage device attached to the target. In this scenario, writing each incoming log message directly onto the external storage device is appreciate, because the storage device might be un-mounted/suddenly removed at any time. Writing each log message immediately avoids the problem of losing too many messages because the file system sync could not be finished before the device has been removed physically from the target. On the other hand the DLT Logstorage feature might be used as well to store a configurable set of logs on any internal, nonvolatile memory (e.g. FLASH storage device). Due to the reason of limited write cycles of a FLASH device the number of write cycles has to be reduced as much as possible. But the drawback of losing log messages in case of an unexpected operating system crash has to be taking into account as well. The obvious idea is to cache incoming log messages in memory and write the log data to disk based on a certain strategy. Incoming log messages are stored in a data cache with a specific size. Depending on user defined strategy, the data cache is written onto the storage device、without relying on the sync mechanism of the file system.
The following strategies are implemented:
Note :
File
value, it is recommened that the following settings must also have same values: NOFiles
, FileSize
and SpecificSize
The ring buffer behaviour can be modified for specific filters by changing the OverwriteBehavior.
The following strategies are implemented:
Routing to network client (e.g. DLT Viewer) can be changed by the DisableNetwork.
The following flags are implemented:
The log level setting of each user context in the logstorage FILTER will be
treated as the highest priority. Other clients (e.g: dlt-control, dlt-viewer)
can update the user context’s log level to a lower level but can not update
to a higher level. In case the clients need to update the user context’s log
level to a higher level, the new macro MaintainLogstorageLogLevel
is
implemented in the [General]
session to allow changing user context’s
log level to any level or maintain the log level of logstorage configuration.
A typical configuration file may look like:
[General]
MaintainLogstorageLogLevel=OFF
By setting MaintainLogstorageLogLevel=OFF
or MaintainLogstorageLogLevel=0
,
the clients are able to update any log level to user contexts.
By setting MaintainLogstorageLogLevel=ON
or MaintainLogstorageLogLevel=1
or not set, the logstorage will maintain its log level as the highest priority.
The DLT Logstorage also provides negative filter feature, which allows filtering unwanted Application or Context.
The following strategies are implemented:
Exclude a pair of Application and Context
[FILTER1]
...
ExcludedLogAppName=LOG
ExcludedContextName=TEST
Exclude single Application or list of Applications
[FILTER1]
...
ExcludedLogAppName=LOG
[FILTER2]
...
ExcludedLogAppName=LOG1,LOG2,LOG3
Exclude single Context or list of Contexts
[FILTER1]
...
ExcludedContextName=TEST
[FILTER2]
...
ExcludedContextName=TEST1,TEST2,TEST3
Note :
DLT offline logstorage does not support multiple Application and multiple Context filter. The following configuration is not supported and the behavior will be undefinded:
[FILTER1]
...
LogAppName=LOG1,LOG2,LOG3
ContextName=TEST1,TEST2,TEST3
[FILTER2]
...
ExcludedLogAppName=LOG1,LOG2,LOG3
ExcludedContextName=TEST1,TEST2,TEST3