Use stat_col storage for stat_cols_info[] array instead of name_desc.
As documented in 65624876f ("MINOR: stats: introduce a more expressive
stat definition method"), stat_col supersedes name_desc storage but
it remains backward compatible. Here we migrate to the new API to be
able to further extend stat_cols_info[] in following patches.
Since b3d5708 ("MINOR: stats: remove implicit static trash_chunk usage")
a segfault can occur when issuing "show schema json" on the stats socket.
Indeed, now the dumping functions don't rely on trash_chunk anymore, but
instead they rely on the appctx->chunk buffer. However, unlike other
stats dumping commands, the "show schema json" only have an io handler,
and no parse function. With other command, the parse function is
responsible for pre-setting some data, including applet ctx reservation.
Thus due to "show schema json" lacking parsing function, the applet ctx is
used uninitialized, which is a bug obviously.
To fix the issue we simply add a parse function for "show schema json",
although all it does for now is calling applet_reserve_svcctx() for the
current applet ctx.
This issue was reported by @dsuch in GH #2825. It must be backported up
to 3.0.
In stats_scope_ptr(), the validity of blk() was assumed using
ALREADY_CHECKED(blk), but we can now use the cleaner ASSUME_NONNULL().
In addition this simplifies the BUG_ON() check that follows.
Provide alternative code during stats dump when stress mode is active.
The objective is to force the applet to yield on every output line. This
allows to easily test reentrant code paths, in particular while adding
and removing server instances.
To support this, output is interrupted every time the output buffer (or
its equivalent) is not empty. Use COND_STRESS() macro to provide default
and stress alternative conditions.
If a server A is deleted while a stats dump is currently on it, deletion
is delayed thanks to reference counting. Server A is nonetheless removed
from the proxy list. However, this list is a single linked list. If the
next server B is deleted and freed immediately, server A would still
point to it. This problem has been solved by the prev_deleted list in
servers.
This model seems correct, but it is difficult to ensure completely its
validity. In particular, it implies when stats dump is resumed, server A
elements will be accessed despite the server being in a half-deleted
state.
Thus, it has been decided to completely ditch the refcount mechanism for
stats dump. Instead, use the watcher element to register every stats
dump currently tracking a server instance. Each time a server is deleted
on the CLI, each stats dump element which may points to it are updated
to access the next server instance, or NULL if this is the last server.
This ensures that a server which was deleted via CLI but not completely
freed is never accessed on stats dump resumption.
Currently, no race condition related to dynamic servers and stats dump
is known. However, as described above, the previous model is deemed too
fragile, as such this patch is labelled as bug-fix. It should be
backported up to 2.6, after a reasonable period of observation. It
relies on the following patch :
MINOR: list: define a watcher type
Servers instance may be removed at runtime. This can occurs during a
stat dump which currently references this server instance. This case is
protected by server refcount to prevent the server immediate release.
CLI output may be interrupted prior to stats dump completion, for
example if client CLI has been disconnected before the full response
transfer. As such, srv_drop() must be called in every stats dump release
callback.
srv_drop() was missing for stats-file dump release callback. This could
cause a race condition which would prevent a server instance to be fully
removed. Fix this by adding srv_drop() invokation into
cli_io_handler_release_dump_stat_file().
This should be backported up to 3.0.
A shared counter is added in the thread context to track the total number of
streams created on the thread. This number is then reported in stats. It
will be a useful information to diagnose some bugs.
A shared counter is added in the thread context to track the current number
of streams. This number is then reported in stats. It will be a useful
information to diagnose some bugs.
Split code related to proxies list looping in cli_parse_clear_counters()
to a new dedicated function. This function is placed in the new module
stats-proxy.
Create a new module stats-proxy. Move stats functions related to proxies
list looping in it. This allows to reduce stats source file dividing its
size by half.
Convert FN_AGE in stat_cols_px[] as generic columns. These values will
be automatically used for dump/preload of a stats-file.
Remove srv_lastsession() / be_lastsession() function which are now
useless as last_sess is calculated via me_generate_field().
Extend generic stat column support to be able to fully support age stats
type. Several changes were required.
On output, me_generate_field() has been updated to report the difference
between the current tick with the stored value for FN_AGE type. Also, if
an age stats is hidden in show stats, -1 is returned instead of an empty
metric, which is the value to mark an age as unset.
On counters preload, load_ctr() was updated to handled FN_AGE. A similar
substraction is performed to the current tick value.
last_change was a member present in both proxy and server struct. It is
used as an age statistics to report the last update of the object.
Move last_change into fe_counters/be_counters. This is necessary to be
able to manipulate it through generic stat column and report it into
stats-file.
Note that there is a change for proxy structure with now 2 different
last_change values, on frontend and backend side. Special care was taken
to ensure that the value is initialized only on the proxy side. The
other value is set to 0 unless a listen proxy is instantiated. For the
moment, only backend counter is reported in stats. However, with now two
distinct values, stats could be extended to report it on both side.
Convert every FN_RATE in stat_cols_px[] to generic column. Thanks to
prior patch, this allows to automatically dump their value into
stats-file and preload corresponding freq-ctr on process startup.
Implement support for FN_RATE stat column into stat-file.
For the output part, only minimal change is required. Reuse the function
read_freq_ctr() to print the same value in both stats output and
stats-file dump.
For counter preloading, define a new utility function
preload_freq_ctr(). This can be used to initialize a freq-ctr type by
preloading previous period value. Reuse this function in load_ctr()
during stats-file parsing.
At the moment, no rate column is defined as generic. Thus, this commit
does not have functional change. This will be changed as soon as FN_RATE
are converted to generic columns.
Move freq-ctr defined in proxy or server structures into their dedicated
fe_counters/be_counters struct.
Functionnaly no change here. This commit will allow to convert rate
stats column to generic one, which is mandatory to manipulate them in
the stats-file.
Currently, only FN_COUNTER are dumped and preloaded via a stats-file.
Thus in several places we relied on the assumption that only FN_COUNTER
are valid in stats-file context.
New stats types will soon be implemented as they are also eligilible to
statistics reloading on process startup. Thus, prepare stats-file
functions to remove any FN_COUNTER restriction.
As one of this change, generate_stat_tree() now uses stcol_is_generic()
for stats name tree indexing before stats-file parsing.
Also related to stats-file parsing, individual counter preloading step
as been extracted from line parsing in a dedicated new function
load_ctr(). This will allow to extend it to support multiple mechanism
of counter preloading depending on the stats type.
req_tot counter is a special case as it is not managed identically
between frontend and backend side.
For the backend side, this metric is available directly into
be_counters, which allows to use a generic stat column definition.
On the frontend side however, the metric value is an aggredate of
multiple fe_counters value. This is the case since the splitting between
HTTP version introduced in the following patch :
9969adbcdc1a79a6e8bb0a6283191d8d330a04f1
MINOR: stats: add by HTTP version cumulated number of sessions and requests
This difference cannot be handled automatically by me_generate_field().
Add a special case in the function to produce it on frontend side
reusing the aggregated value. This not done however for stats-file as
there is no counter to preload.
This commit is the first one of a serie to implement preloading of
haproxy counters via stats-file parsing.
This patch defines a basic apply_stats_file() function. It implements
reading line by line of a stats-file without any parsing for the moment.
It is called automatically on process startup via init().
Define a new CLI command "dump stats-file" with its handler
cli_parse_dump_stat_file(). It will loop twice on proxies_list to dump
first frontend and then backend side. It reuses the common function
stats_dump_stat_to_buffer(), using STAT_F_BOUND to restrict on the
correct side.
A new module stats-file.c is added to regroup function specifics to
stats-file. It defines two main functions :
* stats_dump_file_header() to generate the list of column list prefixed
by the line context, either "#fe" or "#be"
* stats_dump_fields_file() to generate each stat lines. Object without
GUID are skipped. Each stat entry is separated by a comma.
For the moment, stats-file does not support statistics modules. As such,
stats_dump_*_line() functions are updated to prevent looping over stats
module on stats-file output.
Prepare stats function to handle a new format labelled "stats-file". Its
purpose is to generate a statistics dump with a format closed from the
CSV output. Such output will be then used to preload haproxy internal
counters on process startup.
stats-file output differs from a standard CSV on several points. First,
only an excerpt of all statistics is outputted. All values that does not
make sense to preload are excluded. For the moment, stats-file only list
stats fully defined via "struct stat_col" method. Contrary to a CSV, sll
columns of a stats-file will be filled. As such, empty field value is
used to mark stats which should not be outputted.
Some adaptation specifics to stats-file are necessary into
me_generate_field(). First, stats-file will output separatedly values
from frontend and backend sides with their own respective set of
columns. As such, an empty field value is returned if stat is not
defined for either frontend/listener, or backend/server when outputting
the other side. Also, as stats-file does not support empty column,
stcol_hide() is not used for it.
A minor adjustement was necessary for stats_fill_fe_line() to pass
context flags. This is necessary to detect stat output format. All other
listener/server/backend corresponding functions already have it.
Convert most of proxy counters statistics to new "struct stat_col"
definition. Remove their corresponding switch..case entries in
stats_fill_*_line() functions. Their value are automatically calculate
via me_generate_field() invocation.
Along with this, also complete stcol_hide() when some stats should be
hidden.
Only a few counters where not converted. This is because they rely on
values stored outside of fe/be_counters structure, which
me_generate_field() cannot use for now.
Metric style stats can be automatically calculate since the introduction
of metric_generate() when using "struct stat_col" as input. This would
allow to centralize statistics generation. However, some stats are not
outputted under specific condition. For example, health check failures
on a server are only reported if checks are active.
To support this, define a new function metric_hide(). It is called by
metric_generate(). If true, it will skip metric calcuation and return an
empty field value instead. This allows to define "stat_col" metrics and
calculate them with metric_generate() but hiding them under certain
circumstances.
This commit is a direct follow-up of the previous one which define a new
type "struct stat_col" to fully define a statistic entry.
Define a new function metric_generate(). For metrics statistics, it is
able to automatically calculate a stat value field for "offsets" from
"struct stat_col". Use it in stats_fill_*_stats() functions. Maintain a
fallback to previously used switch-case for old-style statistics.
This commit does not introduce functional change as currently no
statistic is defined as "struct stat_col". This will be the subject of a
future commit.
Previously, statistics were simply defined as a list of name_desc, as
for example "stat_cols_px" for proxy stats. No notion of type was fixed
for each stat definition. This correspondance was done individually
inside stats_fill_*_line() functions. This renders the process to
define new statistics tedious.
Implement a more expressive stat definition method via a new API. A new
type "struct stat_col" for stat column to replace name_desc usage is
defined. It contains a field to store the stat nature and format. A
<cap> field is also defined to be able to define a proxy stat only for
certain type of objects.
This new type is also further extended to include counter offsets. This
allows to define a method to automatically generate a stat value field
from a "struct stat_col". This will be the subject of a future commit.
New type "struct stat_col" is fully compatible full name_desc. This
allows to gradually convert stats definition. The focus will be first
for proxies counters to implement statistics preservation on reload.
The name "metrics" was chosen to represent the various list of haproxy
exposed statistics. However, it is deemed as ambiguous as some stats are
indeed metric in the true sense, but some are not, as highlighted by
various "enum field_origin" values.
Replace it by the new name "stat_cols" for statistic columns. Along with
the already existing notion of stat lines it should better reflect its
purpose.
Some flags are defined during statistics generation and output. They use
the prefix STAT_* which is also used for other purposes. Rename them
with the new prefix STAT_F_* to differentiate them from the other
usages.
Several unique names were used for different purposes under statistics
implementation. This caused the code to be difficult to understand.
* stat/stats name is removed when a more specific name could be used
* restrict field usage to purely refer to <struct field> which
represents a raw stat value.
* use "line" naming to represent an array of <struct field>
Info are used to expose haproxy global metrics. It is similar to proxy
statistics and any other module. As such, rename info indexes using
SI_I_INF_* prefix. Also info variable is renamed stat_line_info.
Thanks to this, naming is now consistent between info and other
statistics. It will help to integrate it as a "global" statistics
module.
Statistics were extended with the introduction of stats module. This
mechanism allows to expose various metrics for several haproxy
components. As a consequence of this, some static variables were
transformed to dynamic ones to be able to regroup all statistics
definition.
Rename these variables with more explicit naming :
* stat_lines can be used to generate one line of statistics for any
module using struct field as value
* metrics and metrics_len are used to stored description of metrics
indexed by module
Note that info is not integrated in the statistics module mechanism.
However, it could be done in the future to better reflect its purpose.
This commit is the first one of a serie which adjust naming convention
for stats module. The objective is to remove ambiguity and better
reflect how stats are implemented, especially since the introduction of
stats module.
This patch renames elements related to proxies statistics. One of the
main change is to rename ST_F_* statistics indexes prefix with the new
name ST_I_PX_*. This remove the reference to field which represents
another concept in the stats module. In the same vein, global
stat_fields variable is renamed metrics_px.
This commit is part of a series to align counters usage between
frontends/listeners on one side and backends/servers on the other.
On frontend side, "stot" is the total count of sessions for both proxies
and listeners. For proxies, fe_counters <cum_sess> is correctely used.
The bug is on listeners where <cum_conn> value is returned, which
instead indicates a number of connection. This commit fixes this by
returning <cum_sess> counter value for "stot" metric.
Along this fixes, use the opportunity to report "conn_tot" for listeners
using <cum_conn> value, as for frontend proxies.
This commit fixes a bug but must not be backported as stats output is
changed.
This commit is part of a serie to align counters usage between
frontends/listeners on one side and backends/servers on the other.
"stot" metric refers to the total number of sessions. On backend side,
it is interpreted as a number of streams. Previously, this was accounted
using <cum_sess> be_counters field for servers, but <cum_conn> instead
for backend proxies.
Adjust this by using <cum_sess> for both proxies and servers. As such,
<cum_conn> field can be removed from be_counters.
Note that several diagnostic messages which reports total frontend and
backend connections were adjusted to use <cum_sess>. However, this is an
outdated and misleading information as it does reports streams count on
backend side. These messages should be fixed in a separate commit.
This should be backported to all stable releases.
This commit is the first one of a series which aims to align counters
usage between frontends/listeners on one side and backends/servers on
the other.
Remove <down_trans> field from proxy structure. Use instead the same
name field from be_counters structure, which is already used for
servers.
Extract functions related to HTML stats webpage from stats.c into a new
module named stats-html. This allows to reduce stats.c to roughly half
of its original size.
A static variable trash_chunk was used as implicit buffer in most of
stats output function. It was a oneline buffer uses as temporary storage
before emitting to the final applet or CLI buffer.
Replaces it by a buffer defined in show_stat_ctx structure. This allows
to retrieve it in most of stats output function. An additional parameter
was added for the function where context was not already used. This
renders the code cleaner and will allow to split stats.c in several
source files.
As a result of a new member into show_stat_ctx, per-command context max
size has increased. This forces to increase APPLET_MAX_SVCCTX to ensure
pool size is big enough. Increase it to 128 bytes which includes some
extra room for the future.
When cache and stats applets were changed to use their own buffers, a change
was also performed to no longer access the stream from the I/O
handller. Among other things, the HTTP start-line of the request is now
retrieved to get the method. But, when these changes were brought, the inbuf
buffer allocation failures were not handled.
It is of course not so common. But if this happens, a crash may be
experienced. To fix the issue, we now check for inbuf allocation failures
before accessing it.
No backported needed.
It is the third applet to be refactored to use its own buffers. In addition to
the CLI applet, some I/O handlers of CLI commands were also updated, especially
the stats ones.
Some command I/O handlers were updated to use applet's buffers instead of
channels ones.
Server refcount is used to protect from server deletion while dumping a
server instance, for stats dump on both CLI and HTTP applet. However,
dump can be aborted prematurely before reaching the end. In this case,
server refcount is never decremented.
This bug can cause an inconsistency on servers refcount, preventing them
to be deleted even after "del server" success.
To fix this, implement release handler for both stats CLI and HTTP
applet. Drop server reference if dump was interrupted during servers
loop.
This should be backported up to 2.6.
Global options to disable for zero-copy forwarding are now tested outside
callbacks responsible to perform the forwarding itself. It is cleaner this
way because we don't try at all zero-copy forwarding if at least one side
does not support it. It is equivalent to what was performed before, but it
is simplier this way.
To fix a bug, a flag to announce the capabitlity to support the zero-copy
forwarding on the consumer side will be added on the SE descriptor. So the
old flag SE_FL_MAY_FASTFWD is renamed to indicate it concerns the producer
side. It is now SE_FL_MAY_FASTFWD_PROD. And to prepare addition of the new
flag, the bitfield is a bit reordered.
These both flags are set after releasing the applet, in
appctx_shut(). Concretly, it means the applet is shutdown for reads and
writes. Once set, the applet's I/O handler was no longer called. Tests on
these flags are useless. There is no chance to match them.
This case does not exist yet with the H1 multiplexer, but applets may decide to
not produce data if there is not enough room in the destination buffer (the
applet's outbuf or the opposite SE buffer). It is true for the stats applets for
instance. However this case is not properly handled when the zero-copy
forwarding is in-use.
To fix the issue, the se_done_ff() function was modified to return the number of
bytes really forwarded and to subs for sends if nothing was forwarded while the
zero-copy forwarding was blocked by the producer. On the applet side, we take
care to block the zero-copy forwarding if the applet requests more room. At the
end, zero-copy forwarding is unblocked if something was forwarded.
This way, it is now possible for the stats applet to report a full buffer and
block the zero-copy forwarding, even if the buffer is not really full, by
requesting more room.
No backport needed.
