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.
All responses to the client sent by single method `_write_response`
encode('utf-8') is done only inside this method. It make easier to
support existing code because eliminates need to put b'' everywhere
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`.
Environment variables available to the postmaster can be examined
by non-superusers (e.g. plperl is trusted, yet you can show the environment).
In some environments secrets may be written in environment variables.
Commit 9744019341 introduced the ability to
specify the full Patroni configuration as an environment variable,
PATRONI_CONFIGURATION.
PATRONI_CONFIGURATION will by definition contain secrets, the passwords for superuser,
replcation user etc.
We therefore only retain a small subset of the environment for pg_ctl start, to ensure
no leakage of these values are possible.
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.
Alexander Kukushkin