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.

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