dbschema 0.1.2

Define database schema's as HCL files, and generate idempotent SQL migrations
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121

use anyhow::Result;
use chrono::Local;
use std::collections::HashMap;

use crate::ir::Config;

pub mod json;
pub mod postgres;
pub mod prisma;

pub trait Backend {
    fn name(&self) -> &'static str;
    fn file_extension(&self) -> &'static str;
    fn generate(&self, cfg: &Config, strict: bool) -> Result<String>;
}

/// Registry for managing backends provided by providers.
pub struct BackendRegistry {
    backends: HashMap<String, Box<dyn Backend>>,
}

impl BackendRegistry {
    /// Create a new empty backend registry.
    pub fn new() -> Self {
        Self {
            backends: HashMap::new(),
        }
    }

    /// Register a backend with the registry.
    /// The backend's name() method is used as the key.
    pub fn register(&mut self, backend: Box<dyn Backend>) {
        let name = backend.name().to_string().to_lowercase();
        self.backends.insert(name, backend);
    }

    /// Register a backend with an alias.
    /// This allows the same backend to be accessible by multiple names.
    pub fn register_alias(&mut self, alias: &str, backend: Box<dyn Backend>) {
        self.backends.insert(alias.to_lowercase(), backend);
    }

    /// Get a backend by name (case-insensitive).
    pub fn get(&self, name: &str) -> Option<&dyn Backend> {
        self.backends.get(&name.to_lowercase()).map(|b| &**b)
    }

    /// List all registered backend names.
    pub fn list_backends(&self) -> Vec<&str> {
        self.backends.keys().map(|s| s.as_str()).collect()
    }
}

impl Default for BackendRegistry {
    fn default() -> Self {
        Self::new()
    }
}

pub fn generate_header_comment(backend_name: &str, comment_style: CommentStyle) -> String {
    let timestamp = Local::now().format("%Y-%m-%d %H:%M:%S %Z").to_string();
    let warning = format!(
        "WARNING: This file is auto-generated by dbschema.\n\
         Do not edit this file manually. Any changes will be overwritten\n\
         the next time the schema is regenerated.\n\
         \n\
         Backend: {}\n\
         Generated: {}",
        backend_name, timestamp
    );

    match comment_style {
        CommentStyle::Sql => {
            let lines: Vec<String> = warning.lines().map(|line| format!("-- {}", line)).collect();
            format!("{}\n\n", lines.join("\n"))
        }
        CommentStyle::Prisma => {
            let lines: Vec<String> = warning.lines().map(|line| format!("// {}", line)).collect();
            format!("{}\n\n", lines.join("\n"))
        }
    }
}

pub enum CommentStyle {
    Sql,
    Prisma,
}

/// Create a backend registry with all built-in backends registered.
/// This includes backends from providers as well as standalone backends.
pub fn get_default_backend_registry() -> BackendRegistry {
    let mut registry = BackendRegistry::new();

    // Register provider backends
    let provider_registry = crate::provider::get_default_provider_registry();
    for provider_name in provider_registry.list_providers() {
        if let Some(provider) = provider_registry.get(provider_name) {
            provider.register_backends(&mut registry);
        }
    }

    // Register standalone backends (json, prisma)
    registry.register(Box::new(json::JsonBackend));
    registry.register(Box::new(prisma::PrismaBackend));

    registry
}

/// Get a backend by name. This is a convenience function that creates backends on-demand.
/// For better performance when calling multiple times, consider using get_default_backend_registry()
/// and reuse it, although that requires dealing with lifetimes.
pub fn get_backend(name: &str) -> Option<Box<dyn Backend>> {
    // We need to return a Box<dyn Backend>, so we create backends on-demand
    // This matches the original behavior and avoids lifetime issues
    match name.to_lowercase().as_str() {
        "postgres" | "pg" => Some(Box::new(postgres::PostgresBackend)),
        "json" => Some(Box::new(json::JsonBackend)),
        "prisma" => Some(Box::new(prisma::PrismaBackend)),
        _ => None,
    }
}