Skip to content
Showing user profile of selected author: -

PostgreSQL Project @ GSoC 2021

Wow! The PostgreSQL Project got all 7 proposals accepted into Google Summer of Code 2021!

This year Google changed the participation terms a bit, and cut the time for the students in half. This is supposed to help students who can’t work full-time from home, especially in light of the global pandemic situation. It also means smaller projects, which are easier to handle even for students new to the project.

The PostgreSQL project got a great number of initial applications (29), and we talked with many of the students about refining their proposals. 27 out of the 29 applications were finally submitted by the students. Some are duplicates, some are clearly just copied from somewhere, but many propose good ideas.

After talking with available mentors, and “recruiting” a few more, we settled on 7 final applications, and submitted them to Google.

As usual many of the proposals are not directly developing code for core PostgreSQL, but work on tools and applications from the PostgreSQL ecosystem. Expect some great output over the following months.
 

  • Twitter
  • Bookmark PostgreSQL Project @ GSoC 2021 at del.icio.us
  • Facebook
  • Google Bookmarks
  • FriendFeed
  • Digg PostgreSQL Project @ GSoC 2021
  • Bloglines PostgreSQL Project @ GSoC 2021
  • Technorati PostgreSQL Project @ GSoC 2021
  • Fark this: PostgreSQL Project @ GSoC 2021
  • Bookmark PostgreSQL Project @ GSoC 2021 at YahooMyWeb
  • Bookmark PostgreSQL Project @ GSoC 2021 at Furl.net
  • Bookmark PostgreSQL Project @ GSoC 2021 at reddit.com
  • Bookmark PostgreSQL Project @ GSoC 2021 at blinklist.com
  • Bookmark PostgreSQL Project @ GSoC 2021 at Spurl.net
  • Bookmark PostgreSQL Project @ GSoC 2021 at Simpy.com
  • Bookmark PostgreSQL Project @ GSoC 2021 at blogmarks
  • Bookmark PostgreSQL Project @ GSoC 2021 with wists
  • wong it!
  • Bookmark using any bookmark manager!
  • Stumble It!
  • Identi.ca

Ansible and string comparisation for IDs

Was running in a stupid problem where Ansible (version 2.9.x) throws an error when a variable is defined. The Play:

- name: Check if id is defined
  fail:
    msg: "No id defined for {{ inventory_hostname }}!"
  when: id is not defined or id|length == 0

And the error:

TASK [Check if id is defined] *****************************************
fatal: [xxx.xxx.xxx.xxx]: FAILED! => {"msg": "The conditional check 'id is not defined or id|length == 0' failed. The error was: Unexpected templating type error occurred on ({% if id is not defined or id|length == 0 %} True {% else %} False {% endif %}): object of type 'int' has no len()\n\nThe error appears to be in '/path/to/playbook/configuration.yml': line 57, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n    - name: Check if id is defined\n      ^ here\n"}

Ok, it tries to compare an integer, fine. There are two ways to fix this problem:

1: Change the type to a string by updating the inventory:

From:

id=1

to:

id="1"

But this might have other consequences, as the other parts of the Playbook might depend on this being an integer.

2: Compare as string

when: id is not defined or id|string|length == 0

This casts the integer to a string, and then the length() function works.

  • Twitter
  • Bookmark Ansible and string comparisation for IDs at del.icio.us
  • Facebook
  • Google Bookmarks
  • FriendFeed
  • Digg Ansible and string comparisation for IDs
  • Bloglines Ansible and string comparisation for IDs
  • Technorati Ansible and string comparisation for IDs
  • Fark this: Ansible and string comparisation for IDs
  • Bookmark Ansible and string comparisation for IDs at YahooMyWeb
  • Bookmark Ansible and string comparisation for IDs at Furl.net
  • Bookmark Ansible and string comparisation for IDs at reddit.com
  • Bookmark Ansible and string comparisation for IDs at blinklist.com
  • Bookmark Ansible and string comparisation for IDs at Spurl.net
  • Bookmark Ansible and string comparisation for IDs at Simpy.com
  • Bookmark Ansible and string comparisation for IDs at blogmarks
  • Bookmark Ansible and string comparisation for IDs with wists
  • wong it!
  • Bookmark using any bookmark manager!
  • Stumble It!
  • Identi.ca

Ansible, "copy" module and "become"

For testing I did spin up a couple of new virtual (Ubuntu 20.04 LTS) instances, installed PostgreSQL, and wanted to copy over a .sql file to install in the database:

- name: copy files to PostgreSQL data directory
  copy:
    src: "files/{{ item }}"
    dest: "{{ item }}"
    mode: 0700
  become: yes
  become_user: postgres
  loop:
    - file1.sql
    - file2.sql

And ran into a meaningless error message:

TASK [copy files to PostgreSQL data directory] ***********
fatal: [xxx.xxx.xxx.xxx]: FAILED! => {"msg": "Failed to set permissions on the temporary files Ansible needs to create when becoming an unprivileged user (rc: 1, err: chown: changing ownership of '/var/tmp/ansible-tmp-1618521951.848439-176484068031965/': Operation not permitted\nchown: changing ownership of '/var/tmp/ansible-tmp-1618521951.848439-176484068031965/source': Operation not permitted\n}). For information on working around this, see https://docs.ansible.com/ansible/become.html#becoming-an-unprivileged-user"}

 

 

Continue reading "Ansible, "copy" module and "become""
  • Twitter
  • Bookmark Ansible, "copy" module and "become" at del.icio.us
  • Facebook
  • Google Bookmarks
  • FriendFeed
  • Digg Ansible, "copy" module and "become"
  • Bloglines Ansible, "copy" module and "become"
  • Technorati Ansible, "copy" module and "become"
  • Fark this: Ansible, "copy" module and "become"
  • Bookmark Ansible, "copy" module and "become" at YahooMyWeb
  • Bookmark Ansible, "copy" module and "become" at Furl.net
  • Bookmark Ansible, "copy" module and "become" at reddit.com
  • Bookmark Ansible, "copy" module and "become" at blinklist.com
  • Bookmark Ansible, "copy" module and "become" at Spurl.net
  • Bookmark Ansible, "copy" module and "become" at Simpy.com
  • Bookmark Ansible, "copy" module and "become" at blogmarks
  • Bookmark Ansible, "copy" module and "become" with wists
  • wong it!
  • Bookmark using any bookmark manager!
  • Stumble It!
  • Identi.ca

Make Ansible "postgresql_ping" fail if the database does not exist

Ansible has a very useful module "postgresql_ping" which checks connectivity to the database server. I'm using it in quite a few Playbooks as first step just to ensure that the database server is present - this fails early if there is a problem which otherwise just prevents the rest of the Playbook to work properly.

TASK [Check if database is available]
[WARNING]: PostgreSQL server is unavailable: could not connect to server: No such file or directory         Is the server running locally and accepting         connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
fatal: [127.0.0.1]: FAILED! => {"changed": false, "failed_when_result": true, "is_available": false, "server_version": {}}

 

However this module does not check if the database exists, just if the server is reachable. Example Playbook:

- name: Check if database is available
  postgresql_ping:
    db: "testdb"
  become: yes
  become_user: postgres

When I run the Playbook:

TASK [Check if database is available]
[WARNING]: PostgreSQL server is unavailable: FATAL:  database "testdb" does not exist
ok: [127.0.0.1]

 

As you can see, the database "testdb" does not exist. Which for the module is a reason to raise a warning, but not  a reason to fail.

One possible solution is to let this module do it's work, and add a "postgresql_db" call next, which ensures that the database is created. But not every Playbook is supposed to create and populate a database, and has all the required parameters (owner, encoding, template ect) available. Therefore it would be nice if "postgresql_ping" fails early if the database in question doesn't exist. That's possible, with two more lines of code:

- name: Check if database is available
  postgresql_ping:
    db: "testdb"
  become: yes
  become_user: postgres
  register: ping_database
  failed_when: ping_database.warnings is defined

And the Playbook run:

TASK [Check if database is available]
[WARNING]: PostgreSQL server is unavailable: FATAL:  database "testdb" does not exist
fatal: [127.0.0.1]: FAILED! => {"changed": false, "failed_when_result": true, "is_available": false, "server_version": {}}

Together with "any_errors_fatal: True" this ends the entire Playbook early enough before I have to debug the problem later on.

  • Twitter
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at del.icio.us
  • Facebook
  • Google Bookmarks
  • FriendFeed
  • Digg Make Ansible "postgresql_ping" fail if the database does not exist
  • Bloglines Make Ansible "postgresql_ping" fail if the database does not exist
  • Technorati Make Ansible "postgresql_ping" fail if the database does not exist
  • Fark this: Make Ansible "postgresql_ping" fail if the database does not exist
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at YahooMyWeb
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at Furl.net
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at reddit.com
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at blinklist.com
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at Spurl.net
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at Simpy.com
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist at blogmarks
  • Bookmark Make Ansible "postgresql_ping" fail if the database does not exist with wists
  • wong it!
  • Bookmark using any bookmark manager!
  • Stumble It!
  • Identi.ca