dpcs 0.12.0

Reference implementation of the Data Pipeline Contract Standard (DPCS)
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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

//! Local cache for registry client lookups.

use std::collections::HashMap;
use std::fs;
use std::path::{Path, PathBuf};

use crate::error::{Error, Result};
use crate::model::RegisteredArtifact;

/// Disk/memory cache keyed by registry id + artifact id@version.
#[derive(Debug, Default, Clone)]
pub struct RegistryCache {
    memory: HashMap<String, CachedEntry>,
    root: Option<PathBuf>,
}

#[derive(Debug, Clone)]
struct CachedEntry {
    artifact: RegisteredArtifact,
    content: Option<String>,
    etag: Option<String>,
}

impl RegistryCache {
    /// Create an in-memory cache.
    pub fn memory() -> Self {
        Self::default()
    }

    /// Create a cache that also persists under `root`.
    pub fn disk(root: impl Into<PathBuf>) -> Result<Self> {
        let root = root.into();
        fs::create_dir_all(&root).map_err(|err| Error::Io {
            path: root.clone(),
            source: err,
        })?;
        Ok(Self {
            memory: HashMap::new(),
            root: Some(root),
        })
    }

    fn key(registry_id: &str, artifact_id: &str, version: &str) -> String {
        format!("{registry_id}|{artifact_id}|{version}")
    }

    /// Store artifact metadata (and optional content).
    pub fn put(
        &mut self,
        registry_id: &str,
        artifact: RegisteredArtifact,
        content: Option<String>,
        etag: Option<String>,
    ) -> Result<()> {
        let key = Self::key(registry_id, &artifact.id, &artifact.version);
        if let Some(root) = &self.root {
            let path = root.join(sanitize(&key));
            let payload = serde_json::json!({
                "artifact": artifact,
                "content": content,
                "etag": etag,
            });
            fs::write(
                &path,
                serde_json::to_string_pretty(&payload).map_err(|err| {
                    Error::Serialization(format!("cache serialize failed: {err}"))
                })?,
            )
            .map_err(|err| Error::Io {
                path: path.clone(),
                source: err,
            })?;
        }
        self.memory.insert(
            key,
            CachedEntry {
                artifact,
                content,
                etag,
            },
        );
        Ok(())
    }

    /// Lookup cached artifact.
    pub fn get(
        &self,
        registry_id: &str,
        artifact_id: &str,
        version: &str,
    ) -> Option<(RegisteredArtifact, Option<String>, Option<String>)> {
        let key = Self::key(registry_id, artifact_id, version);
        if let Some(entry) = self.memory.get(&key) {
            return Some((
                entry.artifact.clone(),
                entry.content.clone(),
                entry.etag.clone(),
            ));
        }
        let root = self.root.as_ref()?;
        let path = root.join(sanitize(&key));
        let raw = fs::read_to_string(path).ok()?;
        let value: serde_json::Value = serde_json::from_str(&raw).ok()?;
        let artifact: RegisteredArtifact =
            serde_json::from_value(value.get("artifact")?.clone()).ok()?;
        let content = value
            .get("content")
            .and_then(|v| v.as_str())
            .map(str::to_owned);
        let etag = value
            .get("etag")
            .and_then(|v| v.as_str())
            .map(str::to_owned);
        Some((artifact, content, etag))
    }

    /// Clear memory entries; also removes disk files when configured.
    pub fn clear(&mut self) -> Result<()> {
        self.memory.clear();
        if let Some(root) = &self.root {
            if root.is_dir() {
                for entry in fs::read_dir(root).map_err(|err| Error::Io {
                    path: root.clone(),
                    source: err,
                })? {
                    let entry = entry.map_err(|err| Error::Io {
                        path: root.clone(),
                        source: err,
                    })?;
                    let _ = fs::remove_file(entry.path());
                }
            }
        }
        Ok(())
    }

    /// Cache root directory when disk-backed.
    pub fn root(&self) -> Option<&Path> {
        self.root.as_deref()
    }
}

fn sanitize(key: &str) -> String {
    key.as_bytes().iter().map(|b| format!("{b:02x}")).collect()
}