torrust_tracker_deployer_lib/application/command_handlers/exists/
handler.rs

1//! Exists command handler implementation
2//!
3//! **Purpose**: Check whether an environment exists
4//!
5//! This handler checks whether an environment with the given name exists
6//! in the data directory. It is a read-only operation that does not modify
7//! any state or make any network calls.
8//!
9//! ## Design Rationale
10//!
11//! - "Not found" is a valid result (`exists = false`), NOT an error
12//! - Only repository access failures produce errors
13//! - Returns a simple boolean result via `ExistsResult`
14
15use std::sync::Arc;
16
17use tracing::instrument;
18
19use super::errors::ExistsCommandHandlerError;
20use crate::domain::environment::repository::EnvironmentRepository;
21use crate::domain::EnvironmentName;
22
23/// Result of checking whether an environment exists
24#[derive(Debug, Clone)]
25pub struct ExistsResult {
26    /// The environment name that was checked
27    pub name: String,
28    /// Whether the environment exists
29    pub exists: bool,
30}
31
32/// `ExistsCommandHandler` checks whether an environment exists
33///
34/// **Purpose**: Read-only existence check against the repository
35///
36/// This handler queries the repository to determine if an environment
37/// with the given name exists. It never modifies state or makes network calls.
38pub struct ExistsCommandHandler {
39    repository: Arc<dyn EnvironmentRepository>,
40}
41
42impl ExistsCommandHandler {
43    /// Create a new `ExistsCommandHandler`
44    #[must_use]
45    pub fn new(repository: Arc<dyn EnvironmentRepository>) -> Self {
46        Self { repository }
47    }
48
49    /// Execute the exists command workflow
50    ///
51    /// Checks whether the named environment exists in the repository.
52    ///
53    /// # Arguments
54    ///
55    /// * `env_name` - The name of the environment to check
56    ///
57    /// # Returns
58    ///
59    /// * `Ok(ExistsResult)` - Result indicating whether the environment exists
60    /// * `Err(ExistsCommandHandlerError)` - If the repository check fails
61    ///
62    /// # Errors
63    ///
64    /// Returns an error if:
65    /// * Repository access fails (file system error, permissions, etc.)
66    #[instrument(
67        name = "exists_command",
68        skip_all,
69        fields(
70            command_type = "exists",
71            environment = %env_name
72        )
73    )]
74    pub fn execute(
75        &self,
76        env_name: &EnvironmentName,
77    ) -> Result<ExistsResult, ExistsCommandHandlerError> {
78        let exists = self.repository.exists(env_name)?;
79
80        Ok(ExistsResult {
81            name: env_name.to_string(),
82            exists,
83        })
84    }
85}
torrust_tracker_deployer_lib/application/command_handlers/exists/handler.rs

torrust_tracker_deployer_lib/application/command_handlers/exists/
handler.rs
