where it is not necessary (test_ha, test_ctl, etc...)
It will simplyfy further refactoring and make it possible to install
implementations of AbstractDCS independant of each other.
Originally we were passing postgresql options as an argument of `pg_ctl
start`. It was nice and convenient because doesn't require to touch
configuration files but this method has one significant drawback: it
wasn't possible to change values of options which were passed as an
arguments without restart (event for the case when option reqires only
reload). Instead of doing that (passing options as arguments) we will:
1) rename original postgresql.conf to postgresql-base.conf
2) write options into postgresql.conf which has `include
'postgresql-base.conf'` on the the third line after comment that this
file is generated by Patroni and you should not change it manually
3) listen_addresses and port are still passed as an arguments to the
pg_ctl (just to be foolproof against ALTER SYSTEM set port to 'random')
In addition to that this commit makes some attributes of `Postgresql`
class private (prefixes them with _)
Somehow when you import only urllib3 it's not possible work with
urllib3.exceptions.HTTPError exception (it looks like it is imported
from some other place. from urllib3.exceptions import HTTPError solves
the problem.
A Patroni configuration should be enough for Patronictl
The previous dcs_api url style is still supported.
To remove duplicate magic variables a DCS_DEFAULTS was introduced.
Some behaviour has changed: If you do not specify a DCS at all
(not in configuration, not on commandline, not in environment), it will
not default to etcd://localhost:4001
More test coverage for patronictl
Previously we explicitly injected a replication record into pg_hba.conf.
This doesn't allow users to explicitly write their configurations.
This change will just write the lines specified by the user.
Mostly this tag is necessary to give a hint to load balancer
auto-configuration tool that node should not be included into
LB configuration.
In addition to that Patroni also should not return status_code=200
for a health check if the tag is present and value is not `False`.
Previously we explicitly injected a replication record into pg_hba.conf.
This doesn't allow users to explicitly write their configurations.
This change will just write the lines specified by the user.
Until now get_dcs method was doing absolutely the same job as method
from Patroni class.
In addition to that I did small refactoring and clean up of unit tests
Previously, pg_rewind was called only if a crashed master tried
to rejoin the cluster. It didn't cover the important case of a
master shut down cleanly, but with a combination of a smart
shutdown and subsequently a fast shutdown. Since out pg_rewind
code does not depend on the "uncleanness" of the master's shutdown,
we can call it unconditionally in all cases where the former master
tries to rejoin as a replica.
This resolves #167.
According to https://github.com/zalando/patroni/issues/48 'clonefrom'
tag should be boolean and it should be used to mark node as a suitable
for creation of a new replica from. If there are more then one such node
in the cluster (with tag clonefrom=true), one of them will be chosed
randomly.
Instead of starting it up in "read-only", it wil wait 2 seconds, to give
a time to somebody to prompte and after it will execute normal `recover`
procedure.
Such situation is causing patroni crash. Usually it was happening during
manual failover, after former master has demoted and `reset_cluster`
method has been called. In this case `fetch_cluster` was `False` and
`_load_cluster` method was returning value from `self._cluster`, which
was `None`.
In addition to that rename confusing `Etcd.client` and
`ZooKeeper.client` into `_client`. This attribute is available from
AbstractDCS and people had wrong impression that it provides the same
interface for different DCS implementations, which is obviously not the
case. For Etcd it has type etcd.Client and for ZooKeeper - KazooClient.
Despite this release was very buggy it has really nice features:
* EtcdWatchTimedOut exception is raised when `watch` call timed out
* it supports SRV autodiscovery
Since we already implemented our own SRV discovery this feature is not
really interesting for us, but it solves the problem of having two
requirements files for different python versions, because python-etcd
will install dnspython or dnspython3 as a dependency.
In order to fix https://github.com/jplana/python-etcd/issues/152 and
https://github.com/jplana/python-etcd/pull/154 I had to override
`api_execute` method.
Previously, "without_leader" suffix was used in the name of methods
and functions that initialize a replica without an active replication
connection, and leader was part of the name for parameters and messages
that require an active replication conneciton. Since we support init
from the members other than the leader, those conventions have to be
changed.
At the moment we just replace the master with the
node at the 'clonefrom' tag if it's present. Master
should be available anyway, otherwise, it will not
even try to do cloning.
Acceptance tests:
https://github.com/zalando/patroni/pull/144/commits
Alexander Kukushkin