What is the meaning of the parameters?

Default parameters.yml file

Here is the last version of the default app/config/parameters.yml file. Be sure that yours respects this one. If you don't know which value you need to set, please leave the default one.

parameters:
    database_driver: pdo_sqlite
    database_host: 127.0.0.1
    database_port: null
    database_name: symfony
    database_user: root
    database_password: null
    database_path: '%kernel.root_dir%/../data/db/wallabag.sqlite'
    database_table_prefix: wallabag_
    database_socket: null
    mailer_transport: smtp
    mailer_host: 127.0.0.1
    mailer_user: null
    mailer_password: null
    locale: en
    secret: ovmpmAWXRCabNlMgzlzFXDYmCFfzGv
    twofactor_auth: true
    twofactor_sender: no-reply@wallabag.org
    fosuser_registration: true
    fosuser_confirmation: true
    from_email: no-reply@wallabag.org
    rss_limit: 50
    rabbitmq_host: localhost
    rabbitmq_port: 5672
    rabbitmq_user: guest
    rabbitmq_password: guest
    redis_scheme: tcp
    redis_host: localhost
    redis_port: 6379
    redis_path: null
    redis_password: null

Meaning of each parameter

Database parameters
name default description
database_driver pdo_sqlite Should be pdo_sqlite or pdo_mysql or pdo_pgsql
database_host 127.0.0.1 host of your database (usually localhost or 127.0.0.1)
database_port ~ port of your database (you can leave ~ to use the default one)
database_name symfony name of your database
database_user root user that can write to this database
database_password ~ password of that user
database_path "%kernel.root_dir%/../data/db/wallabag.sqlite" only for SQLite, define where to put the database file. Leave it empty for other database
database_table_prefix wallabag_ all wallabag's tables will be prefixed with that string. You can include a _ for clarity
database_socket null If your database is using a socket instead of tcp, put the path of the socket (other connection parameters will then be ignored)
database_charset utf8mb4 For PostgreSQL & SQLite you should use utf8, for MySQL use utf8mb4 which handle emoji
Configuration to send emails from wallabag
name default description
mailer_transport smtp The exact transport method to use to deliver emails. Valid values are: smtp, gmail, mail, sendmail, null (which will disable the mailer)
mailer_host 127.0.0.1 The host to connect to when using smtp as the transport.
mailer_user ~ The username when using smtp as the transport.
mailer_password ~ The password when using smtp as the transport.
Other wallabag's option
name default description
locale en Default language of your wallabag instance (like en, fr, es, etc.)
secret ovmpmAWXRCabNlMgzlzFXDYmCFfzGv This is a string that should be unique to your application and it's commonly used to add more entropy to security related operations.
twofactor_auth true true to enable Two factor authentication
twofactor_sender no-reply@wallabag.org email of the email sender to receive the two factor code
fosuser_registration true true to enable public registration
fosuser_confirmation true true to send a confirmation by email for each registration
from_email no-reply@wallabag.org email address used in From: field in each email
rss_limit 50 limit for RSS feeds
RabbitMQ configuration
name default description
rabbitmq_host localhost Host of your RabbitMQ
rabbitmq_port 5672 Port of your RabbitMQ
rabbitmq_user guest User that can read queues
rabbitmq_password guest Password of that user
Redis configuration
name default description
redis_scheme tcp Specifies the protocol used to communicate with an instance of Redis. Valid values are: tcp, unix, http
redis_host localhost IP or hostname of the target server (ignored for unix scheme)
redis_port 6379 TCP/IP port of the target server (ignored for unix scheme)
redis_path null Path of the UNIX domain socket file used when connecting to Redis using UNIX domain sockets
redis_password null Password defined in the Redis server configuration (parameter requirepass in redis.conf)