spin_templates/
writer.rs

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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
use std::path::PathBuf;

use anyhow::Context;

pub(crate) struct TemplateOutputs {
    outputs: Vec<TemplateOutput>,
}

pub(crate) enum TemplateOutput {
    WriteFile(PathBuf, Vec<u8>),
    AppendToml(PathBuf, String),
    MergeToml(PathBuf, &'static str, String), // only have to worry about merging into root table for now
    CreateDirectory(PathBuf),
}

impl TemplateOutputs {
    pub fn new(outputs: Vec<TemplateOutput>) -> Self {
        Self { outputs }
    }

    pub async fn write(&self) -> anyhow::Result<()> {
        for output in &self.outputs {
            output.write().await?;
        }
        Ok(())
    }
}

impl TemplateOutput {
    pub async fn write(&self) -> anyhow::Result<()> {
        match &self {
            TemplateOutput::WriteFile(path, contents) => {
                let dir = path.parent().with_context(|| {
                    format!("Can't get directory containing {}", path.display())
                })?;
                tokio::fs::create_dir_all(&dir)
                    .await
                    .with_context(|| format!("Failed to create directory {}", dir.display()))?;
                tokio::fs::write(&path, &contents)
                    .await
                    .with_context(|| format!("Failed to write file {}", path.display()))?;
            }
            TemplateOutput::AppendToml(path, text) => {
                let existing_toml = tokio::fs::read_to_string(path)
                    .await
                    .with_context(|| format!("Can't open {} to append", path.display()))?;
                let new_toml = format!("{}\n\n{}", existing_toml.trim_end(), text);
                tokio::fs::write(path, new_toml)
                    .await
                    .with_context(|| format!("Can't save changes to {}", path.display()))?;
            }
            TemplateOutput::MergeToml(path, target, text) => {
                let existing_toml = tokio::fs::read_to_string(path)
                    .await
                    .with_context(|| format!("Can't open {} to append", path.display()))?;
                let new_toml = merge_toml(&existing_toml, target, text)?;
                tokio::fs::write(path, new_toml)
                    .await
                    .with_context(|| format!("Can't save changes to {}", path.display()))?;
            }
            TemplateOutput::CreateDirectory(dir) => {
                tokio::fs::create_dir_all(dir)
                    .await
                    .with_context(|| format!("Failed to create directory {}", dir.display()))?;
            }
        }
        Ok(())
    }
}

fn merge_toml(existing: &str, target: &str, text: &str) -> anyhow::Result<String> {
    use toml_edit::{DocumentMut, Entry, Item};

    let mut doc: DocumentMut = existing
        .parse()
        .context("Can't merge into the existing manifest - it's not valid TOML")?;
    let merging: DocumentMut = text
        .parse()
        .context("Can't merge snippet - it's not valid TOML")?;
    let merging = merging.as_table();
    match doc.get_mut(target) {
        Some(item) => {
            let Some(table) = item.as_table_mut() else {
                anyhow::bail!("Cannot merge template data into {target} as it is not a table");
            };
            for (key, value) in merging {
                match table.entry(key) {
                    Entry::Occupied(mut e) => {
                        let existing_val = e.get_mut();
                        *existing_val = value.clone();
                    }
                    Entry::Vacant(e) => {
                        e.insert(value.clone());
                    }
                }
            }
        }
        None => {
            let table = Item::Table(merging.clone());
            doc.insert(target, table);
        }
    };
    Ok(doc.to_string())
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn can_insert_variables_in_manifest() {
        let manifest = r#"spin_version = "1"

[[component]]
id = "dummy"
"#;

        let variables = r#"url = { required = true }"#;

        let new = merge_toml(manifest, "variables", variables).unwrap();

        assert_eq!(
            r#"spin_version = "1"

[[component]]
id = "dummy"

[variables]
url = { required = true }
"#,
            new
        );
    }

    #[test]
    fn can_merge_variables_into_manifest() {
        let manifest = r#"spin_version = "1"

[variables]
secret = { default = "1234 but don't tell anyone!" }

[[component]]
id = "dummy"
"#;

        let variables = r#"url = { required = true }"#;

        let new = merge_toml(manifest, "variables", variables).unwrap();

        assert_eq!(
            r#"spin_version = "1"

[variables]
secret = { default = "1234 but don't tell anyone!" }
url = { required = true }

[[component]]
id = "dummy"
"#,
            new
        );
    }
}