swift/doc/source/logs.rst

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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. It is possible to change this format with the log_msg_template config parameter. The default log format is:

{client_ip} {remote_addr} {end_time.datetime} {method} {path} {protocol}
    {status_int} {referer} {user_agent} {auth_token} {bytes_recvd}
    {bytes_sent} {client_etag} {transaction_id} {headers} {request_time}
    {source} {log_info} {start_time} {end_time} {policy_index}

Some keywords, signaled by the (anonymizable) flag, can be anonymized by using the transformer 'anonymized'. The data are applied the hashing method of log_anonymization_method and an optional salt log_anonymization_salt.

Some keywords, signaled by the (timestamp) flag, can be converted to standard dates formats using the matching transformers: 'datetime', 'asctime' or 'iso8601'. Other transformers for timestamps are 's', 'ms', 'us' and 'ns' for seconds, milliseconds, microseconds and nanoseconds. Python's strftime directives can also be used as tranformers (a, A, b, B, c, d, H, I, j, m, M, p, S, U, w, W, x, X, y, Y, Z).

Example {client_ip.anonymized} {remote_addr.anonymized} {start_time.iso8601}

{end_time.H}:{end_time.M} {method} acc:{account} cnt:{container} obj:{object.anonymized}

Log Field Value

client_ip

Swift's guess at the end-client IP, taken from various headers in the request. (anonymizable)

remote_addr

The IP address of the other end of the TCP connection. (anonymizable)

end_time Timestamp of the request. (timestamp)
method The HTTP verb in the request.
path The path portion of the request. (anonymizable)

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. (anonymizable)
user_agent The value of the HTTP User-Agent header. (anonymizable)

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. (anonymizable)
transaction_id The transaction id of the request.
headers The headers given in the request. (anonymizable)
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.

start_time

High-resolution timestamp from the start of the request. (timestamp)

end_time

High-resolution timestamp from the end of the request. (timestamp)

ttfb Duration between the request and the first bytes is sent.
policy_index The value of the storage policy index.

account

The account part extracted from the path of the request. (anonymizable)

container

The container part extracted from the path of the request. (anonymizable)

object

The object part extracted from the path of the request. (anonymizable)

pid PID of the process emitting the log line.

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 (delete)
EA bulk (extract)
AQ account-quotas
CQ container-quotas
CS container-sync
TA common_tempauth
DLO dynamic-large-objects
LE list_endpoints
KS keystoneauth
RL ratelimit
RO read_only
VW versioned_writes
SSC copy
SYM symlink
SH sharding_doc
S3 s3api
OV object_versioning
EQ etag_quoter

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.