Crate questdb_confstr

questdb-confstr

Format

Parser for a configuration string format used by QuestDB clients.

The format is as follows:

service::key1=value1;key2=value2;key3=value3;

A few rules:

• The last semicolon is mandatory.
• Service name and keys are case-sensitive.
• Keys are ASCII alphanumeric and can contain underscores.
• Values are case-sensitive unicode strings which can contain any characters,
  • Except control characters (0x00..=0x1f and 0x7f..=0x9f).
  • If semicolons ; appears in a value, these are escaped as double semicolon ;;.

Grammar

conf_str ::= service "::" params | service
service ::= identifier
params ::= param (";" param)* ";"
param ::= key "=" value
key ::= identifier
value ::= { value_char }

identifier ::= alpha_num_under { alpha_num_under }
alpha_num_under ::= "a".."z" | "A".."Z" | "0".."9" | "_"
value_char ::= non_semicolon_char | escaped_semicolon
escaped_semicolon ::= ";;"
non_semicolon_char ::= ? any unicode character except ';', 0x00..=0x1f and 0x7f..=0x9f ?

Usage

Add dependency to Cargo.toml

cargo add questdb-confstr

Usage

Use the parse_conf_str function to parse into a ConfStr struct.

You can then access the service name as &str and parameters as a &HashMap<String, String>.

Where we use it

We use this config parsing format in our Rust, C, C++ and Python clients.

We also use it to configure object stores for database replication.

Structs

• ConfStr
  Parsed configuration string.
• ParsingError
  The parsing error.

Enums

• ErrorKind
  The type of parsing error.

Functions

• parse_conf_str
  Parse a config string.

Type Aliases

• Key
  Parameter keys are ascii lowercase strings.
• Params
  Parameters are stored in a Vec of (Key, Value) pairs. Keys are always lowercase.
• Position
  Byte position in the input string where the parsing error occurred.
• Value
  Parameter values are strings.