A list of variables is now associated to each tcp-check ruleset. It is more a
less a list of set-var expressions. This list may be filled during the
configuration parsing. The listed variables will then be set during each
execution of the tcp-check healthcheck, at the begining, before execution of the
the first tcp-check rule.
This patch is mandatory to convert all protocol checks to tcp-checks. It is a
way to customize shared tcp-check rulesets.
This option defines a sample expression, evaluated as an integer, to set the
status code (check->code) if a tcp-check healthcheck ends on the corresponding
expect rule.
These options define log-format strings used to produce the info message if a
tcp-check expect rule fails (on-error option) or succeeds (on-success
option). For this last option, it must be the ending rule, otherwise the
parameter is ignored.
It is now possible to extract information from the check input buffer using the
check.payload sample fetch. As req.payload or res.payload, an offset and a
length must be specified.
A new section has been added in the configuration manual. Now check sample
fetches will have to be documented under the section 7.3.7 (Fetching
health-check samples).
When a tcp-check healthcheck fails on a specific rule with no dedicated comment,
we look in previous rules if a comment rule is specified. Now, instead of doing
it during tcp-checks execution, we assign the comment to the corresponding rules
during the configuration parsing. So after HAProxy startup, no more comment
rules remains in a tcp-check ruleset.
It is now possible to specified the healthcheck status to use on error or on
timeout for tcp-check expect rules. First, to define the error status, the
option "error-status" must be used followed by "L4CON", "L6RSP", "L7RSP" or
"L7STS". Then, to define the timeout status, the option "tout-status" must be
used followed by "L4TOUT", "L6TOUT" or "L7TOUT".
These options will be used to convert specific protocol healthchecks (redis,
pgsql...) to tcp-check ones.
x
This converter tranform a integer to its binary representation in the network
byte order. Integer are already automatically converted to binary during sample
expression evaluation. But because samples own 8-bytes integers, the conversion
produces 8 bytes. the htonl converter do the same but for 4-bytes integer.
A global list to tcp-check ruleset can now be used to share common rulesets with
all backends without any duplication. It is mandatory to convert all specific
protocol checks (redis, pgsql...) to tcp-check healthchecks.
To do so, a flag is now attached to each tcp-check ruleset to know if it is a
shared ruleset or not. tcp-check rules defined in a backend are still directly
attached to the proxy and not shared. In addition a second flag is used to know
if the ruleset is inherited from the defaults section.
When a log-format string is parsed, if a sample fetch is found, the flag LW_REQ
is systematically added on the proxy. Unfortunately, this produce a warning
during HAProxy start-up when a log-format string is used for a tcp-check send
rule. Now this flag is only added if the parsed sample fetch depends on HTTP
information.
When a log-format string is evaluated, there is no reason to process sample
fetches only when a stream is defined. Several sample fetches are available
outside the stream scope. All others should handle calls without stream. This
patch is mandatory to support log-format string in tcp-check rules.
An extra parameter for tcp-check send rules can be specified to handle the
string or the hexa string as a log-format one. Using "log-format" option,
instead of considering the data to send as raw data, it is parsed as a
log-format string. Thus it is possible to call sample fetches to customize data
sent to a server. Of course, because we have no stream attached to healthchecks,
not all sample fetches are available. So be careful.
tcp-check set-var(check.port) int(8000)
tcp-check set-var(check.uri) str(/status)
tcp-check connect port var(check.port)
tcp-check send "GET %[check.uri] HTTP/1.0\r\n" log-format
tcp-check send "Host: %[srv_name]\r\n" log-format
tcp-check send "\r\n"
Since we have a session attached to tcp-check healthchecks, It is possible use
sample expression and variables. In addition, it is possible to add tcp-check
set-var rules to define custom variables. So, now, a sample expression can be
used to define the port to use to establish a connection for a tcp-check connect
rule. For instance:
tcp-check set-var(check.port) int(8888)
tcp-check connect port var(check.port)
With this option, it is now possible to use a specific address to open the
connection for a tcp-check connect rule. If the port option is also specified,
it is used in priority.
With this option, it is possible to open a connection from a tcp-check connect
rule using all parameter of the server line, like any other healthcheck. For
now, this parameter is exclusive with all other option for a tcp-check connect
rule.
With this option, it is possible to establish the connection opened by a
tcp-check connect rule using upstream socks4 proxy. Info from the socks4
parameter on the server are used.
Evaluate the registered action_ptr associated with each CHK_ACTION_KW rules from
a ruleset. Currently only the 'set-var' and 'unset-var' are parsed by the
tcp-check parser. Thus it is now possible to set or unset variables. It is
possible to use such rules before the first connect of the ruleset.
Register the custom action rules "set-var" and "unset-var", that will
call the parse_store() command upon parsing.
These rules are thus built and integrated to the tcp-check ruleset, but
have no further effect for the moment.
Add a dedicated vars scope for checks. This scope is considered as part of the
session scope for accounting purposes.
The scope can be addressed by a valid session, even embryonic. The stream is not
necessary.
The scope is initialized after the check session is created. All variables are
then pruned before the session is destroyed.
Create a session for each healthcheck relying on a tcp-check ruleset. When such
check is started, a session is allocated, which will be freed when the check
finishes. A dummy static frontend is used to create these sessions. This will be
useful to support variables and sample expression. This will also be used,
later, by HTTP healthchecks to rely on HTTP muxes.
The loop in tcpcheck_main() function is quite hard to understand. Depending
where we are in the loop, The current_step is the currentely executed rule or
the one to execute on the next call to tcpcheck_main(). When the check result is
reported, we rely on the rule pointed by last_started_step or the one pointed by
current_step. In addition, the loop does not use the common list_for_each_entry
macro and it is thus quite confusing.
So the loop has been totally rewritten and splitted to several functions to
simplify its reading and its understanding. Tcp-check rules are evaluated in
dedicated functions. And a common for_each loop is used and only one rule is
referenced, the current one.
After the configuration parsing, when its validity check, an implicit tcp-check
connect rule is added in front of the tcp-check ruleset if the first non-comment
rule is not a connect one. This implicit rule is flagged to use the default
check parameter.
This means now, all tcp-check rulesets begin with a connect and are never
empty. When tcp-check healthchecks are used, all connections are thus handled by
tcpcheck_main() function.
The keyword 'tcp-check' is now parsed in a dedicated callback function. Thus the
code to parse these rules is now located in checks.c. In addition, a deinit
function have been added to release proxy tcp-check rules, on error or when
HAProxy is stopped.
This patch is based on Gaetan Rivet work. It uses a callback function registerd
on the 'tcp-check' keyword instead, but the spirit is the same.
To allow reusing these blocks without consuming more memory, their list
should be static and share-able accross uses. The head of the list will
be shared as well.
It is thus necessary to extract the head of the rule list from the proxy
itself. Transform it into a pointer instead, that can be easily set to
an external dynamically allocated head.
Parse back-references in comments of tcp-check expect rules. If references are
made, capture groups in the match and replace references to it within the
comment when logging the error. Both text and binary regex can caputre groups
and reference them in the expect rule comment.
[Cf: I slightly updated the patch. exp_replace() function is used instead of a
custom one. And if the trash buffer is too small to contain the comment during
the substitution, the comment is ignored.]
The loop to find the id corresponding to the current rule in
tcpcheck_get_step_id() function has been simplified. And
tcpcheck_get_step_comment() function now only relies on the current rule to find
the rigth comment string. The step id is no longer used. To do so, we iterate
backward from the current step to find the first COMMENT rule immediately
preceedding the expect rule chain.
The rbinary match works similarly to the rstring match type, however the
received data is rewritten as hex-string before the match operation is
done.
This allows using regexes on binary content even with the POSIX regex
engine.
[Cf: I slightly updated the patch. mem2hex function was removed and dump_binary
is used instead.]
On the input buffer, it was mainly done to call regex_exec() function. But
regex_exec2() can be used instead. This way, it is no more required to add the
terminating null byte. For the output buffer, it was only done for debugging
purpose.
Allow declaring tcpcheck connect commands with a new parameter,
"linger". This option will configure the connection to avoid using an
RST segment to close, instead following the four-way termination
handshake. Some servers would otherwise log each healthcheck as
an error.
Some expect rules cannot be satisfied due to inherent ambiguity towards
the received data: in the absence of match, the current behavior is to
be forced to wait either the end of the connection or a buffer full,
whichever comes first. Only then does the matching diagnostic is
considered conclusive. For instance :
tcp-check connect
tcp-check expect !rstring "^error"
tcp-check expect string "valid"
This check will only succeed if the connection is closed by the server before
the check timeout. Otherwise the first expect rule will wait for more data until
"^error" regex matches or the check expires.
Allow the user to explicitly define an amount of data that will be
considered enough to determine the value of the check.
This allows succeeding on negative rstring rules, as previously
in valid condition no match happened, and the matching was repeated
until the end of the connection. This could timeout the check
while no error was happening.
[Cf: I slighly updated the patch. The parameter was renamed and the value is a
signed integer to support -1 as default value to ignore the parameter.]
Reduce copy of parsing portions that is common to all three types of
expect actions.
This reduces the amount of code, helping maintainability and reducing
future change spread.
Functionality is identical.
When receiving additional data while chaining multiple tcp-check expects,
previous inverse expects might have a different result with the new data. They
need to be evaluated again against the new data.
Add a pointer to the first inverse expect rule of the current expect chain
(possibly of length one) to each expect rule. When receiving new data, the
currently evaluated tcp-check rule is set back to this pointed rule.
Fonctionnaly speaking, it is a bug and it exists since the introduction of the
feature. But there is no way for now to hit it because when an expect rule does
not match, we wait for more data, independently on the inverse flag. The only
way to move to the following rule is to be sure no more data will be received.
This patch depends on the commit "MINOR: mini-clist: Add functions to iterate
backward on a list".
[Cf: I slightly updated the patch. First, it only concerns inverse expect
rule. Normal expect rules are not concerned. Then, I removed the BUG tag
because, for now, it is not possible to move to the following rule when the
current one does not match while more data can be received.]
Replace the generic integer with an enumerated list. This allows light
type check and helps debugging (seeing action = 2 in the struct is not
helpful).
TCP check expect matching strings or binary patterns are able to know
prior to applying their match function whether the available data is
already sufficient to attempt the match or not.
As such, on insufficient data the expect is postponed. This behavior
avoids unnecessary matches when the data could not possibly match.
When chaining expect, upon passing the previous and going onto the next
however, this length check is not done again. Then the match is done and
will necessarily fail, triggering a new wait for more data. The end
result is the same for a slightly higher cost.
Check received data length for all expects in a chain.
This bug exists since the introduction of the feature:
Fixes: 5ecb77f4c7 ("MEDIUM: checks: add send/expect tcp based check")
Version 1.5+ impacted.
