Logs

Logs

Swift has quite verbose logging, and the generated logs can be used for cluster monitoring, utilization calculations, audit records, and more. As an overview, Swift’s logs are sent to syslog and organized by log level and syslog facility. All log lines related to the same request have the same transaction id. This page documents the log formats used in the system.

Note

By default, Swift will log full log lines. However, with the log_max_line_length setting and depending on your logging server software, lines may be truncated or shortened. With log_max_line_length < 7, the log line will be truncated. With log_max_line_length >= 7, the log line will be “shortened”: about half the max length followed by ” … ” followed by the other half the max length. Unless you use exceptionally short values, you are unlikely to run across this with the following documented log lines, but you may see it with debugging and error log lines.

Proxy Logs

The proxy logs contain the record of all external API requests made to the proxy server. Swift’s proxy servers log requests using a custom format designed to provide robust information and simple processing. The log format is:

client_ip remote_addr datetime request_method request_path protocol
    status_int referer user_agent auth_token bytes_recvd bytes_sent
    client_etag transaction_id headers request_time source log_info
    request_start_time request_end_time policy_index
Log Field Value
client_ip Swift’s guess at the end-client IP, taken from various headers in the request.
remote_addr The IP address of the other end of the TCP connection.
datetime Timestamp of the request, in day/month/year/hour/minute/second format.
request_method The HTTP verb in the request.
request_path The path portion of the request.
protocol The transport protocol used (currently one of http or https).
status_int The response code for the request.
referer The value of the HTTP Referer header.
user_agent The value of the HTTP User-Agent header.
auth_token The value of the auth token. This may be truncated or otherwise obscured.
bytes_recvd The number of bytes read from the client for this request.
bytes_sent The number of bytes sent to the client in the body of the response. This is how many bytes were yielded to the WSGI server.
client_etag The etag header value given by the client.
transaction_id The transaction id of the request.
headers The headers given in the request.
request_time The duration of the request.
source The “source” of the request. This may be set for requests that are generated in order to fulfill client requests, e.g. bulk uploads.
log_info Various info that may be useful for diagnostics, e.g. the value of any x-delete-at header.
request_start_time High-resolution timestamp from the start of the request.
request_end_time High-resolution timestamp from the end of the request.
policy_index The value of the storage policy index.

In one log line, all of the above fields are space-separated and url-encoded. If any value is empty, it will be logged as a “-“. This allows for simple parsing by splitting each line on whitespace. New values may be placed at the end of the log line from time to time, but the order of the existing values will not change. Swift log processing utilities should look for the first N fields they require (e.g. in Python using something like log_line.split()[:14] to get up through the transaction id).

Note

Some log fields (like the request path) are already url quoted, so the logged value will be double-quoted. For example, if a client uploads an object name with a : in it, it will be url-quoted as %3A. The log module will then quote this value as %253A.

Swift Source

The source value in the proxy logs is used to identify the originator of a request in the system. For example, if the client initiates a bulk upload, the proxy server may end up doing many requests. The initial bulk upload request will be logged as normal, but all of the internal “child requests” will have a source value indicating they came from the bulk functionality.

Logged Source Value Originator of the Request
FP FormPost
SLO Static Large Objects
SW StaticWeb
TU TempURL
BD Bulk Operations (Delete and Archive Auto Extraction) (delete)
EA Bulk Operations (Delete and Archive Auto Extraction) (extract)
CQ Container Quotas
CS Container Sync Middleware
TA TempAuth
DLO Dynamic Large Objects
LE List Endpoints
KS KeystoneAuth
RL Rate Limiting
RO Read Only
VW Object Versioning
SSC Server Side Copy
SYM Symlink
SH Container Sharding

Storage Node Logs

Swift’s account, container, and object server processes each log requests that they receive, if they have been configured to do so with the log_requests config parameter (which defaults to true). The format for these log lines is:

remote_addr - - [datetime] "request_method request_path" status_int
    content_length "referer" "transaction_id" "user_agent" request_time
    additional_info server_pid policy_index
Log Field Value
remote_addr The IP address of the other end of the TCP connection.
datetime Timestamp of the request, in “day/month/year:hour:minute:second +0000” format.
request_method The HTTP verb in the request.
request_path The path portion of the request.
status_int The response code for the request.
content_length The value of the Content-Length header in the response.
referer The value of the HTTP Referer header.
transaction_id The transaction id of the request.
user_agent The value of the HTTP User-Agent header. Swift services report a user-agent string of the service name followed by the process ID, such as "proxy-server <pid of the proxy>" or "object-updater <pid of the object updater>".
request_time The duration of the request.
additional_info Additional useful information.
server_pid The process id of the server
policy_index The value of the storage policy index.
Creative Commons Attribution 3.0 License

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.

swift 2.19.1.dev241