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Redis Backend

The Redis backend enables confd to retrieve configuration data from Redis. It supports string keys, hash fields, and pattern-based key retrieval.

Configuration

Basic Connection

Connect to Redis without authentication:

confd redis --node 127.0.0.1:6379 --onetime

Authentication

Password

confd redis --node 127.0.0.1:6379 --password secret --onetime

Or via environment variable:

export REDIS_PASSWORD=secret
confd redis --node 127.0.0.1:6379 --onetime

Database Selection

Specify a database number (default is 0):

confd redis --node 127.0.0.1:6379/4 --onetime

Unix Socket

Connect via Unix socket:

confd redis --node /var/run/redis/redis.sock --onetime

Key Separator

By default, confd uses / as the key separator. Use --separator to change this:

confd redis --node 127.0.0.1:6379 --separator : --onetime

This transforms /myapp/database/url to myapp:database:url when querying Redis.

Options

Flag Description Default
-n, --node Redis server address (host:port or socket path) -
--password Redis password -
--separator Character to replace / in keys /

Data Types

The Redis backend supports multiple data types:

Redis Type confd Behavior
String Returns value directly
Hash Returns all fields as nested keys
Keys (pattern) Scans matching keys

String Keys

redis-cli SET /myapp/database/url "db.example.com"

Access as /myapp/database/url.

Hash Fields

redis-cli HSET /myapp/database url "db.example.com" user "admin" password "secret"

Access fields as /myapp/database/url, /myapp/database/user, etc.

Basic Example

Set keys in Redis:

redis-cli SET /myapp/database/url "db.example.com"
redis-cli SET /myapp/database/user "admin"
redis-cli SET /myapp/database/password "secret123"

Create template resource (/etc/confd/conf.d/myapp.toml):

[template]
src = "myapp.conf.tmpl"
dest = "/etc/myapp/config.conf"
keys = [
  "/myapp/database",
]

Create template (/etc/confd/templates/myapp.conf.tmpl):

[database]
url = {{getv "/myapp/database/url"}}
user = {{getv "/myapp/database/user"}}
password = {{getv "/myapp/database/password"}}

Run confd:

confd redis --node 127.0.0.1:6379 --onetime

Advanced Example

Using Hash for Grouped Config

Store related config in a hash:

redis-cli HSET /myapp/database url "db.example.com" user "admin" password "secret"
redis-cli HSET /myapp/cache host "redis.example.com" port "6379"

Template:

[database]
url = {{getv "/myapp/database/url"}}
user = {{getv "/myapp/database/user"}}

[cache]
host = {{getv "/myapp/cache/host"}}
port = {{getv "/myapp/cache/port"}}

Using Custom Separator

If your Redis keys use : as separator:

redis-cli SET myapp:database:url "db.example.com"
confd redis --node 127.0.0.1:6379 --separator : --onetime

confd will transform /myapp/database/url to myapp:database:url.

Redis Sentinel (Manual)

Connect to a Redis instance behind Sentinel by specifying the master's address:

# Get master address from Sentinel
redis-cli -h sentinel1.example.com -p 26379 SENTINEL get-master-addr-by-name mymaster

# Use that address with confd
confd redis --node <master-ip>:<master-port> --watch

Watch Mode Support

Watch mode is supported for the Redis backend. confd uses Redis keyspace notifications via PubSub.

confd redis --node 127.0.0.1:6379 --watch

Enable Keyspace Notifications

Redis must be configured to emit keyspace notifications:

redis-cli CONFIG SET notify-keyspace-events AKE

Or in redis.conf:

notify-keyspace-events AKE
  • A - Alias for all events
  • K - Keyspace events
  • E - Keyevent events

confd watches for these events: set, del, append, rename_from, rename_to, expire, incrby, incrbyfloat, hset, hincrby, hincrbyfloat, hdel.

Per-Resource Backend Configuration

Instead of using the global backend, individual template resources can specify their own Redis backend configuration. This allows mixing backends within a single confd instance.

Add a [backend] section to your template resource file:

[template]
src = "myapp.conf.tmpl"
dest = "/etc/myapp/config.conf"
keys = [
  "/myapp/database",
]

[backend]
backend = "redis"
nodes = ["redis.example.com:6379"]
client_key = "secretpassword"
separator = ":"

Available backend options:

  • backend - Must be "redis"
  • nodes - Array of Redis server addresses (host:port or socket path)
  • client_key - Redis password
  • separator - Character to replace / in keys (default: /)

Connection Behavior

  • Connection timeout: 1 second
  • Automatic reconnection: Connections are tested with PING before use
  • Multiple nodes: Tries each node in order until one connects (no clustering support)