If /task_manager/wait_task/ unregisters the task, then there is no
way to examine children failures, since their statuses can be checked
only through their parent.
Currently, when a child task is unregistered, it is still kept by its parent. This leads
to excessive memory usage, especially when the tasks are configured to be kept in task
manager after they are finished (task_ttl_in_seconds).
Introduce task_essentials struct which keeps only data necesarry for task manager API.
When a task which has a parent is finished, a foreign pointer to it in its parent is replaced
with respective task_essentials. Once a parent task is finished it is also folded into
its parent (if it has one). Children details of a folded task are lost, unless they
(or some of their subtrees) failed. That is, when a task is finished, we keep:
- a root task (until it is unregistered);
- task_essentials of root's direct children;
- a path (of task_essentials) from root to each failed task (so that the reason
of a failure could be examined).
The API req->param["name"] to access parameters in the path part of the
URL was buggy - it forgot to do URL decoding and the result of our use
of it in Scylla was bugs like #5883 - where special characters in certain
REST API requests got botched up (encoded by the client, then not
decoded by the server).
The solution is to replace all uses of req->param["name"] by the new
req->get_path_param("name"), which does the decoding correctly.
Unfortunately we needed to change 104 (!) callers in this patch, but the
transformation is mostly mechanical and there is no functional changes in
this patch. Another set of changes was to bring req, not req->param, to
a few functions that want to get the path param.
This patch avoids the numerous deprecation warnings we had before, and
more importantly, it fixes#5883.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
If std::vector is resized its iterators and references may
get invalidated. While task_manager::task::impl::_children's
iterators are avoided throughout the code, references to its
elements are being used.
Since children vector does not need random access to its
elements, change its type to std::list<foreign_task_ptr>, which
iterators and references aren't invalidated on element insertion.
Fixes: #16380.
Closesscylladb/scylladb#16381
Before returning task status, wait_task waits for it to finish with
done() method and calls get() on a resulting future.
If requested task fails, an exception will be thrown and user will
get internal server error instead of failed task status.
Result of done() method is ignored.
Fixes: #14914.
Closes#14915
In task manager and task manager test rest apis when a task or module
which does not exist is requested, we get Internal Server Error.
In such cases, wrap thrown exceptions in bad_param_exception
to respond with Bad Request code.
Modify test accordingly.
it turns out we have `using namespace httpd;` in seastar's
`request_parser.rl`, and we should not rely on this statement to
expose the symbols in `seatar::httpd` to `seastar` namespace.
in this change,
* api/*.hh: all httpd symbols are referenced by `httpd::*`
instead of being referenced as if they are in `seastar`.
* api/*.cc: add `using namespace seastar::httpd`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
seastar::httpd::request was deprecated in favor of `seastar::http::request`
since bdd5d929891d2cb821eca25896e25ed4ff658b7a.
so let's use the latter. this change also silences the warning of:
```
/home/kefu/dev/scylladb/api/authorization_cache.cc: In function ‘void api::set_authorization_cache(http_context&, seastar::httpd::routes&, seastar::sharded<auth::service>&)’:
/home/kefu/dev/scylladb/api/authorization_cache.cc:19:104: error: ‘using seastar::httpd::request = struct seastar::http::request’ is deprecated: Use http::request instead [-Werror=deprecated-declarations]
19 | httpd::authorization_cache_json::authorization_cache_reset.set(r, [&auth_service] (std::unique_ptr<request> req) -> future<json::json_return_type> {
| ^~~~~~~
```
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Task ttl can be set with task manager test api, which is disabled
in release mode.
Move get_and_update_ttl from task manager test api to task manager
api, so that it can be used in release mode.
Closes#12894
Sometimes to debug some task manager module, we may want to inspect
the whole tree of descendants of some task.
To make it easier, an api call getting a list of statuses of the requested
task and all its descendants in BFS order is added.
Sometimes we may need task status to be nothrow move constructible.
httpd::task_manager_json::task_status does not satisfy this requirement.
retrieve_status returns future<full_task_status> instead of future<task_status>
to provide an intermediate struct with better properties. An argument
is passed by reference to prevent the necessity to copy foreign_ptr.
It is convenient to create many different tasks implementations
representing more and more specific parts of the operation in
a module. Presenting all of them through the api makes it cumbersome
for user to navigate and track, though.
Flag internal is added to task_manager::task::impl so that the tasks
could be filtered before they are sent to user.
The implementation of a task manager api layer. It provides
methods to list the modules registered in task_manager, list
tasks belonging to the given module, abort, wait for or retrieve
a status of the given task.
