spec_driven_docs/services/
installer.rs

1//! Instance installation: project the embedded payload into a target.
2//!
3//! The chezmoi vocabulary applies: the embedded payload and profile are the
4//! source state, the computed projection is the target state, the repository
5//! on disk is the destination state, and the manifest — written last — is
6//! the persistent entry state. The whole target state is computed before a
7//! byte lands; a non-empty target previews by default; every destination is
8//! guarded; and any failure mid-apply rolls the target back. What the
9//! payload contains is `embedded`'s and the profiles' business.
10
11use std::collections::BTreeMap;
12
13use camino::{Utf8Path, Utf8PathBuf};
14
15use crate::adapters::fs::{DestinationRefusal, check_destination, write_file};
16use crate::domain::manifest::{
17    CANON_SOURCE, MANIFEST_PATH, Manifest, PlanZone, SCHEMA_VERSION, validate_docs_scratch_path,
18    validate_plan_zone_path,
19};
20use crate::domain::ownership::{AdoptedEntry, IntegrationBlock, ManagedEntry, Sha256};
21use crate::domain::profile::{ProfileId, resolve_destination};
22use crate::domain::version::CanonVersion;
23use crate::error::AppError;
24use crate::services::hooks_render::{RenderOptions, render_block};
25use crate::services::verifier;
26
27/// What an installation was asked to do.
28#[derive(Debug, Clone)]
29pub struct InitOptions {
30    /// The absolute target repository.
31    pub target: Utf8PathBuf,
32    /// The profile to project.
33    pub profile: ProfileId,
34    /// Write even into a non-empty target with no instance.
35    pub apply: bool,
36    /// Preview only, regardless of the target's state.
37    pub dry_run: bool,
38    /// The plan zone to record; `None` keeps whatever is recorded.
39    pub plan_zone: Option<PlanZone>,
40    /// The docs scratch to record. `None` keeps whatever is recorded, and
41    /// `Some(None)` clears it.
42    pub docs_scratch: Option<Option<Utf8PathBuf>>,
43}
44
45/// What an installation did.
46#[derive(Debug)]
47pub struct InitOutcome {
48    /// Every line to print: the proposed destinations, then any notices.
49    pub lines: Vec<String>,
50    /// Whether files were written.
51    pub applied: bool,
52}
53
54fn canonical_target(target: &Utf8Path) -> Result<Utf8PathBuf, AppError> {
55    if !target.is_absolute() {
56        return Err(AppError::Usage("target must be absolute".to_string()));
57    }
58    if !target.is_dir() {
59        return Err(AppError::Usage(format!("unresolved target: {target}")));
60    }
61    let canonical = std::fs::canonicalize(target)?;
62    let canonical = Utf8PathBuf::from_path_buf(canonical)
63        .map_err(|p| AppError::Usage(format!("target is not UTF-8: {}", p.display())))?;
64    if canonical.as_str().chars().all(|c| c == '/') {
65        return Err(AppError::Usage("refusing root target".to_string()));
66    }
67    let mut ancestor = Some(canonical.as_path());
68    while let Some(dir) = ancestor {
69        if let Ok(cargo) = std::fs::read_to_string(dir.join("Cargo.toml"))
70            && cargo.contains("name = \"spec-driven-docs\"")
71        {
72            return Err(AppError::Usage(
73                "target is inside the canon checkout".to_string(),
74            ));
75        }
76        ancestor = dir.parent();
77    }
78    Ok(canonical)
79}
80
81fn target_has_content(target: &Utf8Path) -> Result<bool, AppError> {
82    for entry in target.read_dir_utf8()? {
83        let entry = entry?;
84        if entry.file_name() != ".git" {
85            return Ok(true);
86        }
87    }
88    Ok(false)
89}
90
91/// One field of whatever manifest the target already carries.
92///
93/// Read as free JSON rather than through [`Manifest::parse`]: a reinstall
94/// over a record of another schema version must still carry the operator's
95/// declared values forward, and a typed parse would refuse to read it.
96pub(crate) fn recorded_field(target: &Utf8Path, key: &str) -> Option<serde_json::Value> {
97    std::fs::read_to_string(target.join(MANIFEST_PATH))
98        .ok()
99        .and_then(|text| serde_json::from_str::<serde_json::Value>(&text).ok())
100        .and_then(|value| value.get(key).cloned())
101        .filter(|value| !value.is_null())
102}
103
104fn installed_at(target: &Utf8Path) -> String {
105    recorded_field(target, "installed_at")
106        .and_then(|value| value.as_str().map(String::from))
107        .unwrap_or_else(|| {
108            jiff::Timestamp::now()
109                .strftime("%Y-%m-%dT%H:%M:%SZ")
110                .to_string()
111        })
112}
113
114/// The plan zone to record: the flag, else the recorded value, else none.
115///
116/// An omitted flag never clears a declared value. `sdd upgrade` reinstalls
117/// with no flag at all, so "absent means the default" would erase the
118/// operator's declaration on every upgrade.
119///
120/// A recorded value this binary cannot decode refuses rather than defaults,
121/// for the same reason: writing the default over it would erase a
122/// declaration silently, which is the failure the preservation exists to
123/// prevent.
124///
125/// # Errors
126///
127/// [`AppError::ManifestInvalid`] when a value is recorded in a shape this
128/// binary does not understand.
129pub(crate) fn resolved_plan_zone(
130    target: &Utf8Path,
131    flag: Option<&PlanZone>,
132) -> Result<PlanZone, AppError> {
133    if let Some(zone) = flag {
134        return Ok(zone.clone());
135    }
136    let Some(recorded) = recorded_field(target, "plan_zone") else {
137        return Ok(PlanZone::default());
138    };
139    let zone: PlanZone = serde_json::from_value(recorded).map_err(|source| {
140        AppError::ManifestInvalid(format!(
141            "the recorded plan_zone is in a shape this sdd does not read ({source}); \
142             upgrade sdd, or re-declare it with --plan-zone"
143        ))
144    })?;
145    // The same invariants the argument enforces. Carried forward unchecked,
146    // a hand-edited path fails the post-write verification instead, which
147    // rolls the whole target back and names no repair.
148    if let Some(path) = zone.path()
149        && let Err(error) = validate_plan_zone_path(path)
150    {
151        return Err(AppError::ManifestInvalid(format!(
152            "the recorded plan_zone is not usable ({error}); re-declare it with --plan-zone"
153        )));
154    }
155    Ok(zone)
156}
157
158/// The docs scratch to record: the flag, else the recorded value, else none.
159///
160/// The flag is two-level on purpose: absent keeps what is recorded, and
161/// `--docs-scratch none` clears it.
162///
163/// # Errors
164///
165/// [`AppError::ManifestInvalid`] when the recorded value is not a string.
166pub(crate) fn resolved_docs_scratch(
167    target: &Utf8Path,
168    flag: Option<&Option<Utf8PathBuf>>,
169) -> Result<Option<Utf8PathBuf>, AppError> {
170    if let Some(declared) = flag {
171        return Ok(declared.clone());
172    }
173    let Some(recorded) = recorded_field(target, "docs_scratch") else {
174        return Ok(None);
175    };
176    let path = recorded
177        .as_str()
178        .filter(|path| !path.is_empty())
179        .map(Utf8PathBuf::from)
180        .ok_or_else(|| {
181            AppError::ManifestInvalid(format!(
182                "the recorded docs_scratch is not a path ({recorded}); \
183                 re-declare it with --docs-scratch"
184            ))
185        })?;
186    if let Err(error) = validate_docs_scratch_path(&path) {
187        return Err(AppError::ManifestInvalid(format!(
188            "the recorded docs_scratch is not usable ({error}); \
189             re-declare it with --docs-scratch"
190        )));
191    }
192    Ok(Some(path))
193}
194
195struct TargetState {
196    files: Vec<(Utf8PathBuf, Vec<u8>)>,
197    lines: Vec<String>,
198}
199
200#[allow(clippy::too_many_lines)]
201fn compute_target_state(target: &Utf8Path, options: &InitOptions) -> Result<TargetState, AppError> {
202    let profile = options.profile;
203    let declaration = profile.profile();
204    let mut files: Vec<(Utf8PathBuf, Vec<u8>)> = Vec::new();
205    let mut lines = Vec::new();
206    let mut managed_entries = Vec::new();
207    let mut adopted_entries = Vec::new();
208
209    for projection in declaration.managed {
210        let bytes = crate::embedded::asset(projection.source)
211            .ok_or_else(|| anyhow::anyhow!("payload asset missing: {}", projection.source))?;
212        let destination = Utf8PathBuf::from(projection.destination);
213        managed_entries.push(ManagedEntry {
214            source: projection.source.into(),
215            destination: destination.clone(),
216            sha256: Sha256::of(bytes),
217        });
218        lines.push(destination.to_string());
219        files.push((destination, bytes.to_vec()));
220    }
221
222    for projection in declaration.adopted {
223        let seed = crate::embedded::asset(projection.source)
224            .ok_or_else(|| anyhow::anyhow!("payload asset missing: {}", projection.source))?;
225        let destination = resolve_destination(projection.destination, declaration.docs_root);
226        let existing = target.join(&destination);
227        let bytes = if existing.is_file() {
228            std::fs::read(&existing)?
229        } else {
230            seed.to_vec()
231        };
232        adopted_entries.push(AdoptedEntry {
233            source: projection.source.into(),
234            destination: destination.clone(),
235            sha256: Sha256::of(&bytes),
236            baseline_sha256: Sha256::of(seed),
237        });
238        lines.push(destination.to_string());
239        files.push((destination, bytes));
240    }
241
242    let config_path = target.join(".pre-commit-config.yaml");
243    let host = if config_path.is_file() {
244        std::fs::read_to_string(&config_path)?
245    } else {
246        "repos:\n".to_string()
247    };
248    let (base, _) = crate::domain::marker::split_block(&host)?;
249    let indent = crate::domain::marker::splice_indent(&base)?;
250    let block = render_block(&RenderOptions {
251        docs_root: declaration.docs_root.to_string(),
252        indent,
253        ..RenderOptions::default()
254    });
255    let spliced = crate::domain::marker::splice(&base, &block)?;
256    let marker_hash = crate::domain::marker::block_hash(&spliced)
257        .ok_or_else(|| anyhow::anyhow!("the rendered block lost its markers"))?;
258    lines.push(".pre-commit-config.yaml".to_string());
259    files.push((
260        Utf8PathBuf::from(".pre-commit-config.yaml"),
261        spliced.into_bytes(),
262    ));
263
264    let mut integration_blocks = vec![IntegrationBlock {
265        path: ".pre-commit-config.yaml".into(),
266        marker_hash,
267    }];
268
269    // The root AGENTS.md documentation block: the seam that makes SimpleEnglish
270    // arrive by default. A symlinked host is refused before it is read, so a
271    // link cannot redirect the read outside the target.
272    let agents_relative = Utf8Path::new("AGENTS.md");
273    if target.join(agents_relative).is_symlink() {
274        return Err(AppError::Refused(
275            "AGENTS.md is a symlink; refusing to write the documentation block through it"
276                .to_string(),
277        ));
278    }
279    let agents_host = if target.join(agents_relative).is_file() {
280        std::fs::read_to_string(target.join(agents_relative))?
281    } else {
282        String::new()
283    };
284    let agents_block =
285        crate::services::agents_render::render_block(&declaration.docs_root.to_string());
286    let agents = crate::domain::marker::place_agents_block(&agents_host, &agents_block)?;
287    let agents_hash = crate::domain::marker::block_hash_with(
288        &agents,
289        crate::domain::marker::AGENTS_BEGIN,
290        crate::domain::marker::AGENTS_END,
291    )
292    .ok_or_else(|| anyhow::anyhow!("the rendered AGENTS.md block lost its markers"))?;
293    // An old unmarked documentation section is preserved, never deleted; the
294    // note tells the operator to remove the duplicate by hand.
295    if agents_host.contains("## Documentation")
296        && crate::domain::marker::block_region_with(
297            &agents_host,
298            crate::domain::marker::AGENTS_BEGIN,
299            crate::domain::marker::AGENTS_END,
300        )
301        .is_none()
302    {
303        lines.push(
304            "note: AGENTS.md carries an unmarked '## Documentation' section; the managed block was appended and the old section left in place — remove it by hand".to_string(),
305        );
306    }
307    lines.push("AGENTS.md".to_string());
308    files.push((agents_relative.to_path_buf(), agents.into_bytes()));
309    integration_blocks.push(IntegrationBlock {
310        path: "AGENTS.md".into(),
311        marker_hash: agents_hash,
312    });
313
314    let manifest = Manifest {
315        schema_version: SCHEMA_VERSION,
316        canon_version: CanonVersion::current(),
317        canon_source: CANON_SOURCE.to_string(),
318        profile,
319        docs_root: declaration.docs_root,
320        installed_at: installed_at(target),
321        plan_zone: resolved_plan_zone(target, options.plan_zone.as_ref())?,
322        docs_scratch: resolved_docs_scratch(target, options.docs_scratch.as_ref())?,
323        managed_files: managed_entries,
324        adopted_files: adopted_entries,
325        integration_blocks,
326    };
327    lines.push(MANIFEST_PATH.to_string());
328    files.push((
329        Utf8PathBuf::from(MANIFEST_PATH),
330        manifest.to_json().into_bytes(),
331    ));
332
333    Ok(TargetState { files, lines })
334}
335
336fn refusal_line(destination: &Utf8Path, refusal: &DestinationRefusal) -> String {
337    match refusal {
338        DestinationRefusal::SymlinkEscape => {
339            format!("destination escapes the target through a symlink: {destination}")
340        }
341        DestinationRefusal::FileBlocksDirectory(blocked) => {
342            format!("a file blocks a directory the install needs: {blocked}")
343        }
344        DestinationRefusal::NotARegularFile => {
345            format!("destination exists and is not a regular file: {destination}")
346        }
347    }
348}
349
350fn apply(target: &Utf8Path, state: &TargetState) -> Result<(), AppError> {
351    let mut ordered: Vec<&(Utf8PathBuf, Vec<u8>)> = state.files.iter().collect();
352    ordered.sort_by(|a, b| a.0.as_str().as_bytes().cmp(b.0.as_str().as_bytes()));
353
354    for (destination, _) in &ordered {
355        check_destination(target, destination)
356            .map_err(|refusal| AppError::Refused(refusal_line(destination, &refusal)))?;
357    }
358
359    let mut backups: BTreeMap<Utf8PathBuf, Option<Vec<u8>>> = BTreeMap::new();
360    let rollback = |backups: &BTreeMap<Utf8PathBuf, Option<Vec<u8>>>| -> Vec<Utf8PathBuf> {
361        let mut unrestored = Vec::new();
362        for (destination, previous) in backups {
363            let full = target.join(destination);
364            let restored = previous.as_ref().map_or_else(
365                || std::fs::remove_file(&full).is_ok() || !full.exists(),
366                |bytes| write_file(&full, bytes).is_ok(),
367            );
368            if !restored {
369                unrestored.push(destination.clone());
370            }
371        }
372        unrestored
373    };
374    // The cause travels with the refusal: the caller has already lost the
375    // written tree by the time it reads this, so a bare "aborted" leaves
376    // nothing to act on.
377    let abort = |unrestored: Vec<Utf8PathBuf>, cause: &str| {
378        if unrestored.is_empty() {
379            AppError::Refused(format!("apply aborted; the target was restored: {cause}"))
380        } else {
381            let paths: Vec<&str> = unrestored.iter().map(|p| p.as_str()).collect();
382            AppError::Refused(format!(
383                "apply aborted and restoration is incomplete; verify by hand: {}: {cause}",
384                paths.join(" ")
385            ))
386        }
387    };
388
389    for (destination, _) in &ordered {
390        let full = target.join(destination);
391        let previous = if full.is_file() {
392            Some(std::fs::read(&full).map_err(|source| {
393                AppError::Refused(format!("cannot back up {destination}: {source}"))
394            })?)
395        } else {
396            None
397        };
398        backups.insert((*destination).clone(), previous);
399    }
400
401    let write_all = || -> std::io::Result<()> {
402        for (destination, bytes) in &ordered {
403            if destination.as_str() != MANIFEST_PATH {
404                write_file(&target.join(destination), bytes)?;
405            }
406        }
407        for (destination, bytes) in &ordered {
408            if destination.as_str() == MANIFEST_PATH {
409                write_file(&target.join(destination), bytes)?;
410            }
411        }
412        Ok(())
413    };
414
415    if let Err(source) = write_all() {
416        return Err(abort(
417            rollback(&backups),
418            &format!("write failed: {source}"),
419        ));
420    }
421
422    match verifier::verify(target) {
423        Ok(report) if report.failures == 0 => Ok(()),
424        Ok(report) => {
425            let failures: Vec<&str> = report
426                .lines
427                .iter()
428                .filter(|line| line.starts_with("FAIL"))
429                .map(String::as_str)
430                .collect();
431            let cause = failures.join("; ");
432            Err(abort(rollback(&backups), &cause))
433        }
434        Err(source) => Err(abort(
435            rollback(&backups),
436            &format!("the written target could not be verified: {source}"),
437        )),
438    }
439}
440
441/// Install or reinstall an instance.
442///
443/// # Errors
444///
445/// [`AppError::Usage`] for a target the arguments cannot mean,
446/// [`AppError::Marker`] for a configuration whose markers cannot be trusted,
447/// and [`AppError::Refused`] when the apply could not complete — the target
448/// is restored before that returns.
449pub fn init(options: &InitOptions) -> Result<InitOutcome, AppError> {
450    let target = canonical_target(&options.target)?;
451    let forced_dry = !options.apply
452        && !options.dry_run
453        && target_has_content(&target)?
454        && !target.join(MANIFEST_PATH).is_file();
455    let dry = options.dry_run || forced_dry;
456
457    let state = compute_target_state(&target, options)?;
458    let mut lines = state.lines.clone();
459
460    if dry {
461        if forced_dry {
462            lines.push(
463                "DRY RUN: the target is a non-empty repository with no instance; re-run with --apply to write these files"
464                    .to_string(),
465            );
466        }
467        lines.push("DRY RUN: no files written".to_string());
468        return Ok(InitOutcome {
469            lines,
470            applied: false,
471        });
472    }
473
474    apply(&target, &state)?;
475    Ok(InitOutcome {
476        lines,
477        applied: true,
478    })
479}
spec_driven_docs/services/installer.rs

spec_driven_docs/services/
installer.rs
