Sonic Configuration

File: config.cfg

All available configuration options are commented below, with allowed values:

[server]

log_level (type: string, allowed: debug, info, warn, error, default: error) — Verbosity of logging, set it to error in production

[channel]

inet (type: string, allowed: IPv4 / IPv6 + port, default: [::1]:1491) — Host and TCP port Sonic Channel should listen on
tcp_timeout (type: integer, allowed: seconds, default: 300) — Timeout of idle/dead client connections to Sonic Channel
auth_password (type: string, allowed: password values, default: none) — Authentication password required to connect to the channel (optional but recommended)

[channel.search]

query_limit_default (type: integer, allowed: numbers, default: 10) — Default search results limit for a query command (if the LIMIT command modifier is not used when issuing a QUERY command)
query_limit_maximum (type: integer, allowed: numbers, default: 100) — Maximum search results limit for a query command (if the LIMIT command modifier is being used when issuing a QUERY command)
query_alternates_try (type: integer, allowed: numbers, default: 4) — Number of alternate words that look like query word to try if there are not enough query results (if zero, no alternate will be tried; if too high there may be a noticeable performance penalty)
suggest_limit_default (type: integer, allowed: numbers, default: 5) — Default suggested words limit for a suggest command (if the LIMIT command modifier is not used when issuing a SUGGEST command)
suggest_limit_maximum (type: integer, allowed: numbers, default: 20) — Maximum suggested words limit for a suggest command (if the LIMIT command modifier is being used when issuing a SUGGEST command)
list_limit_default (type: integer, allowed: numbers, default: 100) — Default listed words limit for a list command (if the LIMIT command modifier is not used when issuing a LIST command)
list_limit_maximum (type: integer, allowed: numbers, default: 500) — Maximum listed words limit for a list command (if the LIMIT command modifier is being used when issuing a LIST command)

[store]

[store.kv]

path (type: string, allowed: UNIX path, default: ./data/store/kv/) — Path to the Key-Value database store
retain_word_objects (type: integer, allowed: numbers, default: 1000) — Maximum number of objects a given word in the index can be linked to (older objects are cleared using a sliding window)

[store.kv.pool]

inactive_after (type: integer, allowed: seconds, default: 1800) — Time after which a cached database is considered inactive and can be closed (if it is not used, ie. re-activated)

[store.kv.database]

flush_after (type: integer, allowed: seconds, default: 900) — Time after which pending database updates should be flushed from memory to disk (increase this delay if you encounter high-CPU usage issues when a flush task kicks-in; this value should be lower than store.kv.pool.inactive_after)
compress (type: boolean, allowed: true, false, default: true) — Whether to compress database or not (uses Zstandard)
parallelism (type: integer, allowed: numbers, default: 2) — Limit on the number of compaction and flush threads that can run at the same time
max_files (type: integer, allowed: numbers, no default) — Maximum number of database files kept open at the same time per-database (if any; otherwise there are no limits)
max_compactions (type: integer, allowed: numbers, default: 1) — Limit on the number of concurrent database compaction jobs
max_flushes (type: integer, allowed: numbers, default: 1) — Limit on the number of concurrent database flush jobs
write_buffer (type: integer, allowed: numbers, default: 16384) — Maximum size in KB of the database write buffer, after which data gets flushed to disk (ie. 16384 is 16MB; the size should be a multiple of 1024, eg. 128 * 1024 = 131072 for 128MB)
write_ahead_log (type: boolean, allowed: true, false, default: true) — Whether to enable Write-Ahead Log or not (it avoids losing non-flushed data in case of server crash)

[store.fst]

path (type: string, allowed: UNIX path, default: ./data/store/fst/) — Path to the Finite-State Transducer database store

[store.fst.pool]

inactive_after (type: integer, allowed: seconds, default: 300) — Time after which a cached graph is considered inactive and can be closed (if it is not used, ie. re-activated)

[store.fst.graph]

consolidate_after (type: integer, allowed: seconds, default: 180) — Time after which a graph that has pending updates should be consolidated (increase this delay if you encounter high-CPU usage issues when a consolidation task kicks-in; this value should be lower than store.fst.pool.inactive_after)
max_size (type: integer, allowed: numbers, default: 2048) — Maximum size in KB of the graph file on disk, after which further words are not inserted anymore (ie. 2048 is 2MB; the size should be a multiple of 1024, eg. 8 * 1024 = 8192 for 8MB; use this limit to prevent heavy graphs to be consolidating forever; this limit is enforced in pair with store.fst.graph.max_words, whichever is reached first)
max_words (type: integer, allowed: numbers, default: 250000) — Maximum number of words that can be held at the same time in the graph, after which further words are not inserted anymore (use this limit to prevent heavy graphs to be consolidating forever; this limit is enforced in pair with store.fst.graph.max_size, whichever is reached first)

You are allowed to use environment variables in the configuration file.

You can provide them as follows:

[channel]

auth_password = "${env.SECRET}"

Then, you can run Sonic providing a defined environment variable:

SECRET=secretphrase ./sonic -c /path/to/config.cfg

Note that this can only be used with string-like values.