Destroyed servers were still shown as a part of the servers resource
collection.
If a parameter defined in persisted configurations was replaced, the value
would be appended to itself after it was replaced.
Return correct error codes for internal errors.
The server check was checking for old parameter locations.
Service parameters can now be altered with a PUT request to the REST
API. This allows general level parameters to be altered.
Module specific parameters need to be altered with a different mechanism,
namely the module command system. This requires that a generic way to call
a function needs to be devised.
When a persisted configuration file is read, the values in it are
considered to be more up-to-date than the ones in the main configuration
file. This allows all objects to be persisted in a more complete form
making it easier to change configuration values at runtime.
This change is intended to help make runtime alterations to services
possible.
The PATCH method isn't supported in older versions of microhttpd. As this
functionality wasn't used, it can be removed until it is needed. The PUT
method already allows updates by defining complete resources so PATCH is
only an improvement, not a requirement.
The `user`, `password`, `version_string` and `weightby` values should be
allocated as a part of the service structure. This allows them to be
modified at runtime without having to worry about memory allocation
problems.
Although this removes the problem of reallocation, it still does not make
the updating of the strings thread-safe. This can cause invalid values to
be read from the service strings.
If a monitor is started and stopped before the external monitoring thread
has had time to start, a deadlock will occur.
The first thing that the monitoring threads do is read the monitor handle
from the monitor object. This handle is given as the return value of
startMonitor and it is stored in the monitor object. As this can still be
NULL when the monitor thread starts, the threads use locks to prevent
this.
The correct way to prevent this is to pass the handle as the thread
parameter so that no locks are required.
Monitor resources can now be altered with a PUT request. The method allows
alterations on all parameters that the maxadmin `alter monitor` command
allows.
The /sessions/ resource was not implemented due to changes in the core
polling mechanics. With the new worker thread messaging system, sessions
can be listed in a safe manner.
The service, filter and monitor resources now have a "parameters" value
which contains a set of all configuration parameters for that object. This
set contains both standard and non-standard parameters.
Also fixed a mistake in the constant name definitions for the monitor
parameters "events" and "script".
The service resource now exposes the parameters that were given to
it. This allows general service parameters to be changed at runtime
through the REST API.
The alteration function is only called when the value of a parameter
changes. This removes some of the redundant logging that was caused by
calling the alteration function with the same values.
A self link to the resource itself provides a convenient way for the
client to request a resource, modify it and call the self link to update
it. This removes some of the burden on the client to keep track of the
resource links by placing these in the resource itself.
All resources now support HEAD and OPTIONS methods.
The HEAD response is generated by truncating a GET request on the same
resource. This does not work with other methods as they could require a
message body.
The server can now be modified with a PUT request of a modified server
resource. The server resource was reorganized to have the parameters as a
separate entity from the other more general entities of the resource.
The PUT/POST functions return a more appropriate error message when no
request body is provided.
Moved some of the constant names used in server.cc into the config.h
header.
Now all relevant and working core configuration parameters have constants
for their names. This removes some of the risk that comes with the
repetition of the same parameter name in more than place.
The parameter names for monitors and servers now use a set of constant
names. This removes some of the errors caused by spelling mistakes when
the same parameter name is repeated in multiple places.
The service, filter and listener parameters should also be converted to
constants. This allows for a consistent user experience.
The actual list of headers is not known when the request is first
generated. This prevents the headers from being generated in admin.cc
which handles things on a lower level.
The moving of the header generation is done with the OPTIONS method in
mind. This header needs to be generated inside the RootResource class
which manages the navigation of the resources.
Cleaned up various parts of the resource, request and response class
headers.
Moved `using` declarations into .cc files.
Made the Resource class non-copyable as it isn't really meant to be
copied.
The data was not processed correctly and instead an error was sent to the
client as soon as the request arrived.
Created a class that somewhat abstracts the internals of the client
request processing.
The relationships from servers to services and monitors and filters to
services were not implemented. Now each server lists the services and
monitors that use it and each filter lists the services that use the
filter.
This enables the creation of a server and linking of that server to
services and monitors in one atomic operation.
The JSON API (http://jsonapi.org/) specifies a way to express relations in
a somewhat generic way. By moving towards a more generic schema for the
resources, it will be easier to handle the modification of the relations
between these resources.
When a resource has a relation to another resource, it should be expressed
as a working link to the resource. By passing the hostname of the server
to the functions, we are able to generate working relation links.
The resources are now declared by simply typing the path that they match
and providing a callback for that path. This makes it easier to add new
resources without having to create a new class for each added resource
endpoint. It also removes some of the pathname processing that was done
inside the child class handler functions.
The standard response headers are now generated at a higher level. This
reduces the scope of the HttpResponse class making it a leaner wrapper
around a few simple variables, namely the JSON body of the response.
The HttpRequest now exposes the Host header that the client sent. This
allows resource relations to be real links that work without modification.
If a resource can be accessed from more than one place, it should be a
link. The previous change that duplicated the content for nested resources
wasn't a very clean solution. With links, the content is easier to browse
using a normal browser.
The admin interface now supports Basic Access authentication. This is not
a secure method of authentication and it should not be used without
unencrypted connections.
Made the admin interface port, authentication, username and password
configurable.
The HTTP side of the REST API is better handled with an actual
library. The libmicrohttpd library provides a convenient way of handling
the HTTP traffic between the clients and MaxScale.
All routers except the binlogrouter now fully implement the JSON
diagnostic entry point. The binlogrouter needs to be handled in a separate
commit as it produces a large amount of diagnostic output.
The modules that implement a diagnostics entry point now return a JSON
type object. This removes the need to format data inside the modules.
The module implementations of these are not yet complete which means that
MaxScale will fail to compile.
As a service is a collection of other resources, it makes sense to expand
those resources that were previously expressed as relative paths. This way
the API can be readily consumed without altering the pathnames to
links. The downside to this is the increased bandwidth consumption and
possible excess data.
