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Initial commit: OCI image mounting via containers-storage

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slocker-lite validates an OCI Image Layout tar, imports its layers into
containers-storage's layer store in order, and mounts the assembled image
using fuse-overlayfs, printing the resulting merged path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
Viorel Munteanu
2026-08-10 08:12:50 +00:00
commit a301dfb44f
16 changed files with 1141 additions and 0 deletions
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.gitignore
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# Meson build directory
/buildDir/
# Meson subprojects: keep the .wrap files, ignore fetched sources / download cache
/subprojects/*/
/subprojects/packagecache/
/subprojects/.wraplock
# JetBrains IDE
.idea/
# Claude Code session resume note (local-only, not part of the project)
/RESUME
CLAUDE.md
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# CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
## Project state
`slocker-lite` (C++20, built with Meson) mounts an OCI Image Layout tar (`oci-layout` +
`index.json` + `blobs/sha256/*`, as produced by `skopeo`/`podman save --format
oci-archive`/modern `docker save`) using `containers-storage` and `fuse-overlayfs`. Given
an image tar path, it validates the layout, imports each layer into containers-storage's
layer store in order (chained by parent), mounts the assembled top layer, and prints the
resulting merged path. There is no README or broader architecture doc yet — treat this
repo as still early-stage.
Source layout (all under `src/`):
- `main.cpp` — CLI entry point, dependency checks, orchestration.
- `oci_image.{h,cpp}` — validates/parses the OCI Image Layout tar (libarchive +
nlohmann_json) and extracts layer blobs.
- `containers_storage.{h,cpp}` — wraps the `containers-storage` CLI (`import-layer`,
`mount`), forcing `fuse-overlayfs` as the overlay `mount_program`.
- `process.{h,cpp}` — argv-based subprocess helper (fork/execvp/pipe, no shell).
Errors are logged via `spdlog::error`; every external command is also traced at debug
level in `run_process()` (`src/process.cpp`) — visible via `SPDLOG_LEVEL=debug`, since
spdlog's default level is `info` — and a failed external command additionally logs a
`spdlog::warn`, which is visible by default (no env var needed). The final "mounted
image at: ..." success line is direct stdout program output, not a log.
Because `containers-storage mount` runs rootless, the resulting mount lives in a private
user+mount namespace; the printed path is only directly usable from within that same
namespace (e.g. via `containers-storage unshare`), not from an arbitrary external shell.
## Build & test commands
Build directory is `buildDir/` (already configured).
- Configure (only needed if `buildDir/` is missing or deleted): `meson setup buildDir`
- Build: `meson compile -C buildDir` (or `ninja -C buildDir`)
- Run the executable: `./buildDir/slocker_lite <image.tar>`
- Run tests: `meson test -C buildDir`
## Code style
- Null-pointer checks: prefer `if (!ptr)` / `if (ptr)` over `if (ptr == nullptr)` / `if (ptr != nullptr)`.
## Licensing
- Every `.c`/`.cpp`/`.h` file under `src/` must start with the GPLv2-or-later copyright
header (see any existing file under `src/` for the exact text).
- After adding a new source file under `src/`, run `./add-license.sh` from the repo
root to prepend the header (it reads `copyright-header` and inserts it via `sed`,
skipping files that already have it, so it's safe to re-run at any time).
## Build configuration notes
- `meson.build` sets `warning_level=3` and `cpp_std=c++20` — keep new code warning-clean under `-Wall -Wextra -Wpedantic`-equivalent settings.
- The single Meson `test()` target runs `slocker_lite` against a fixture OCI image tar generated at build time by `tests/gen_fixture.py` (a `custom_target`) and checks its exit code (no test framework is wired in yet).
COPYING
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GNU GENERAL PUBLIC LICENSE
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(at your option) any later version.
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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add-license.sh
Executable
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#! /bin/bash
if [[ $1 = -f ]]; then
shift
for i in "$@"; do
grep -q 'GNU General Public License' "$i" || sed -i '0 r copyright-header' "$i"
done
else
find src/ \( -name \*.c -o -name \*.cpp -o -name \*.h \) -exec "$0" -f {} +
fi
copyright-header
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
meson.build
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project('slocker-lite', 'cpp',
version : '0.0.1',
default_options : ['warning_level=3', 'cpp_std=c++20'])
fmt_dep = dependency('fmt')
catch2_dep = dependency('catch2', required : get_option('enable_tests'))
yaml_dep = dependency('yaml-0.1')
archive_dep = dependency('libarchive')
json_dep = dependency('nlohmann_json')
spdlog_dep = dependency('spdlog')
conf_data = configuration_data()
conf_data.set_quoted('PACKAGE', meson.project_name())
conf_data.set_quoted('VERSION', meson.project_version())
conf_data.set10('ENABLE_TESTS', get_option('enable_tests'))
configure_file(output : 'config.h', configuration : conf_data)
slocker_lite = executable('slocker_lite',
['src/main.cpp', 'src/process.cpp', 'src/oci_image.cpp', 'src/containers_storage.cpp'],
include_directories : include_directories('.'),
dependencies : [fmt_dep, catch2_dep, yaml_dep, archive_dep, json_dep, spdlog_dep],
install : true)
fixture_tar = custom_target('oci-fixture',
output : 'fixture.tar',
command : [find_program('python3'), files('tests/gen_fixture.py'), '@OUTPUT@'])
test('test', slocker_lite, args : [fixture_tar])
meson_options.txt
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option('enable_tests', type : 'boolean', value : true, description : 'Enable the Catch2 test dependency and -t test invocation')
src/containers_storage.cpp
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#include "containers_storage.h"
#include "process.h"
namespace {
std::string trim(const std::string& s) {
size_t begin = s.find_first_not_of(" \t\r\n");
if (begin == std::string::npos) {
return "";
}
size_t end = s.find_last_not_of(" \t\r\n");
return s.substr(begin, end - begin + 1);
}
} // namespace
std::string kMountProgram;
std::optional<std::string> import_layer(const std::filesystem::path& diff_file,
const std::string& parent_id) {
std::vector<std::string> argv = {
"containers-storage", "import-layer", "--file", diff_file.string(),
"--storage-opt", "overlay.mount_program=" + kMountProgram};
if (!parent_id.empty()) {
argv.push_back(parent_id);
}
ProcessResult result = run_process(argv);
std::string id = trim(result.stdout_output);
if (result.exit_code != 0 || id.empty()) {
return std::nullopt;
}
return id;
}
std::optional<std::string> mount_layer(const std::string& layer_id) {
std::vector<std::string> argv = {
"containers-storage", "mount", "--storage-opt",
"overlay.mount_program=" + kMountProgram, layer_id};
ProcessResult result = run_process(argv);
std::string path = trim(result.stdout_output);
if (result.exit_code != 0 || path.empty()) {
return std::nullopt;
}
return path;
}
src/containers_storage.h
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#pragma once
#include <filesystem>
#include <optional>
#include <string>
// Absolute path to the fuse-overlayfs binary, passed to containers-storage as
// overlay.mount_program so it performs the actual overlay mounting. Set once in main()
// after find_in_path() resolves it.
extern std::string kMountProgram;
// Runs `containers-storage import-layer --storage-opt overlay.mount_program=<path>
// [--file diff_file] [parent_id]`. Returns the new layer's ID (trimmed stdout) or
// nullopt on failure (containers-storage's own stderr is inherited/visible).
std::optional<std::string> import_layer(const std::filesystem::path& diff_file,
const std::string& parent_id);
// Runs `containers-storage mount --storage-opt overlay.mount_program=<path> <layer_id>`.
// Returns the merged directory path (trimmed stdout) or nullopt on failure.
std::optional<std::string> mount_layer(const std::string& layer_id);
src/main.cpp
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#include <array>
#include <cstdlib>
#include <filesystem>
#include <optional>
#include <string_view>
#include <unistd.h>
#include <fmt/core.h>
#include <spdlog/cfg/env.h>
#include <spdlog/spdlog.h>
#include "containers_storage.h"
#include "oci_image.h"
namespace {
constexpr std::array<std::string_view, 2> kRequiredTools = {"containers-storage", "bwrap"};
bool is_executable_file(const std::filesystem::path& path) {
std::error_code ec;
return std::filesystem::is_regular_file(path, ec) && access(path.c_str(), X_OK) == 0;
}
std::optional<std::filesystem::path> find_in_path(std::string_view name) {
const char* path_env = std::getenv("PATH");
if (!path_env) {
return std::nullopt;
}
std::string_view path{path_env};
for (size_t start = 0; start <= path.size();) {
size_t end = path.find(':', start);
if (end == std::string_view::npos) {
end = path.size();
}
std::filesystem::path dir{path.substr(start, end - start)};
if (!dir.empty()) {
std::filesystem::path candidate = dir / name;
if (is_executable_file(candidate)) {
return candidate;
}
}
start = end + 1;
}
return std::nullopt;
}
} // namespace
bool check_required_dependencies() {
bool all_found = true;
for (auto name : kRequiredTools) {
if (!find_in_path(name)) {
spdlog::error("required dependency not found in PATH: {}", name);
all_found = false;
}
}
return all_found;
}
int main(int argc, char* argv[]) {
spdlog::cfg::load_env_levels();
if (argc != 2) {
spdlog::error("usage: {} <image.tar>", argv[0]);
return 1;
}
const std::filesystem::path image_tar = argv[1];
if (!check_required_dependencies()) {
return 1;
}
auto mount_program = find_in_path("fuse-overlayfs");
if (!mount_program) {
spdlog::error("fuse-overlayfs not found in PATH");
return 1;
}
kMountProgram = mount_program->string();
auto layers = read_oci_layers(image_tar);
if (!layers) {
return 1;
}
std::string parent_id;
for (const auto& layer : *layers) {
std::filesystem::path tmp_file =
std::filesystem::temp_directory_path() /
fmt::format("slocker-lite-{}-{}", getpid(), oci_digest_hex(layer.digest));
if (!extract_blob_to_file(image_tar, oci_digest_hex(layer.digest), tmp_file)) {
return 1;
}
auto layer_id = import_layer(tmp_file, parent_id);
std::filesystem::remove(tmp_file);
if (!layer_id) {
spdlog::error("failed to import layer {}", layer.digest);
return 1;
}
parent_id = *layer_id;
}
auto merged = mount_layer(parent_id);
if (!merged) {
spdlog::error("failed to mount assembled image");
return 1;
}
fmt::print("mounted image at: {}\n", *merged);
return 0;
}
src/oci_image.cpp
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#include "oci_image.h"
#include <archive.h>
#include <archive_entry.h>
#include <fmt/core.h>
#include <nlohmann/json.hpp>
#include <spdlog/spdlog.h>
#include <fstream>
#include <functional>
namespace {
using json = nlohmann::json;
std::string_view normalize_entry_path(std::string_view name) {
if (name.substr(0, 2) == "./") {
name.remove_prefix(2);
}
return name;
}
// Reads a single tar entry's content, calling `sink` with each chunk of data as it's
// read. `sink` is only invoked for the entry whose normalized path equals `target_name`.
// Returns true if the entry was found (regardless of whether it was empty).
bool for_each_chunk_in_entry(const std::filesystem::path& tar_path, std::string_view target_name,
const std::function<void(const char*, size_t)>& sink) {
struct archive* a = archive_read_new();
archive_read_support_filter_all(a);
archive_read_support_format_tar(a);
if (archive_read_open_filename(a, tar_path.c_str(), 65536) != ARCHIVE_OK) {
archive_read_free(a);
return false;
}
bool found = false;
struct archive_entry* entry;
while (archive_read_next_header(a, &entry) == ARCHIVE_OK) {
if (normalize_entry_path(archive_entry_pathname(entry)) != target_name) {
archive_read_data_skip(a);
continue;
}
found = true;
const void* buff;
size_t size;
int64_t offset;
while (true) {
int rc = archive_read_data_block(a, &buff, &size, &offset);
if (rc == ARCHIVE_EOF) {
break;
}
if (rc != ARCHIVE_OK) {
found = false;
break;
}
sink(static_cast<const char*>(buff), size);
}
break;
}
archive_read_free(a);
return found;
}
std::optional<std::string> read_entry_to_string(const std::filesystem::path& tar_path,
std::string_view target_name) {
std::string content;
bool found = for_each_chunk_in_entry(tar_path, target_name, [&](const char* data, size_t size) {
content.append(data, size);
});
if (!found) {
return std::nullopt;
}
return content;
}
} // namespace
std::string oci_digest_hex(std::string_view digest) {
constexpr std::string_view prefix = "sha256:";
if (digest.substr(0, prefix.size()) == prefix) {
digest.remove_prefix(prefix.size());
}
return std::string(digest);
}
bool extract_blob_to_file(const std::filesystem::path& tar_path, std::string_view digest_hex,
const std::filesystem::path& out_file) {
std::string entry_name = fmt::format("blobs/sha256/{}", digest_hex);
std::ofstream out(out_file, std::ios::binary | std::ios::trunc);
if (!out) {
spdlog::error("failed to open {} for writing", out_file.string());
return false;
}
bool found = for_each_chunk_in_entry(tar_path, entry_name,
[&](const char* data, size_t size) { out.write(data, static_cast<std::streamsize>(size)); });
if (!found) {
spdlog::error("blob {} not found in {}", entry_name, tar_path.string());
return false;
}
return true;
}
std::optional<std::vector<OciLayer>> read_oci_layers(const std::filesystem::path& tar_path) {
auto layout = read_entry_to_string(tar_path, "oci-layout");
if (!layout) {
spdlog::error("not an OCI image tar: missing oci-layout");
return std::nullopt;
}
try {
[[maybe_unused]] json parsed_layout = json::parse(*layout);
} catch (const json::parse_error& e) {
spdlog::error("oci-layout is not valid JSON: {}", e.what());
return std::nullopt;
}
auto index_content = read_entry_to_string(tar_path, "index.json");
if (!index_content) {
spdlog::error("not an OCI image tar: missing index.json");
return std::nullopt;
}
json index;
try {
index = json::parse(*index_content);
} catch (const json::parse_error& e) {
spdlog::error("index.json is not valid JSON: {}", e.what());
return std::nullopt;
}
std::string manifest_digest;
for (const auto& m : index.value("manifests", json::array())) {
if (m.value("mediaType", "") == "application/vnd.oci.image.manifest.v1+json") {
manifest_digest = m.value("digest", "");
break;
}
}
if (manifest_digest.empty()) {
spdlog::error("index.json has no OCI image manifest entry");
return std::nullopt;
}
std::string manifest_entry = fmt::format("blobs/sha256/{}", oci_digest_hex(manifest_digest));
auto manifest_content = read_entry_to_string(tar_path, manifest_entry);
if (!manifest_content) {
spdlog::error("missing image manifest blob {}", manifest_digest);
return std::nullopt;
}
json manifest;
try {
manifest = json::parse(*manifest_content);
} catch (const json::parse_error& e) {
spdlog::error("image manifest {} is not valid JSON: {}", manifest_digest, e.what());
return std::nullopt;
}
std::vector<OciLayer> layers;
for (const auto& l : manifest.value("layers", json::array())) {
OciLayer layer;
layer.digest = l.value("digest", "");
layer.media_type = l.value("mediaType", "");
if (layer.digest.empty()) {
spdlog::error("image manifest {} has a layer with no digest", manifest_digest);
return std::nullopt;
}
layers.push_back(std::move(layer));
}
if (layers.empty()) {
spdlog::error("image manifest {} has no layers", manifest_digest);
return std::nullopt;
}
return layers;
}
src/oci_image.h
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#pragma once
#include <filesystem>
#include <optional>
#include <string>
#include <string_view>
#include <vector>
struct OciLayer {
std::string digest; // "sha256:<hex>", as it appears in the manifest
std::string media_type;
};
// Validates that `tar_path` is an OCI Image Layout tar (oci-layout + index.json +
// a referenced blobs/sha256/<digest> image manifest) and returns its layers in
// base-to-top order. Logs a specific error via fmt and returns nullopt if anything
// required is missing or malformed.
std::optional<std::vector<OciLayer>> read_oci_layers(const std::filesystem::path& tar_path);
// Extracts the raw bytes of blobs/sha256/<digest_hex> from `tar_path` into `out_file`.
// Returns false (and logs) if the entry isn't found.
bool extract_blob_to_file(const std::filesystem::path& tar_path,
std::string_view digest_hex,
const std::filesystem::path& out_file);
// Strips the "sha256:" algorithm prefix from a digest string, e.g.
// "sha256:abcd" -> "abcd". Returns the input unchanged if there is no such prefix.
std::string oci_digest_hex(std::string_view digest);
src/process.cpp
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#include "process.h"
#include <sys/wait.h>
#include <unistd.h>
#include <cstring>
#include <fmt/ranges.h>
#include <spdlog/spdlog.h>
ProcessResult run_process(const std::vector<std::string>& argv) {
spdlog::debug("running external command: {}", fmt::join(argv, " "));
int stdout_pipe[2];
if (pipe(stdout_pipe) != 0) {
return {-1, ""};
}
pid_t pid = fork();
if (pid < 0) {
close(stdout_pipe[0]);
close(stdout_pipe[1]);
return {-1, ""};
}
if (pid == 0) {
close(stdout_pipe[0]);
dup2(stdout_pipe[1], STDOUT_FILENO);
close(stdout_pipe[1]);
std::vector<char*> c_argv;
c_argv.reserve(argv.size() + 1);
for (const auto& arg : argv) {
c_argv.push_back(const_cast<char*>(arg.c_str()));
}
c_argv.push_back(nullptr);
execvp(c_argv[0], c_argv.data());
const char* msg = "run_process: execvp failed\n";
write(STDERR_FILENO, msg, std::strlen(msg));
_exit(127);
}
close(stdout_pipe[1]);
std::string output;
char buffer[4096];
ssize_t n;
while ((n = read(stdout_pipe[0], buffer, sizeof(buffer))) > 0) {
output.append(buffer, static_cast<size_t>(n));
}
close(stdout_pipe[0]);
int status = 0;
waitpid(pid, &status, 0);
int exit_code = WIFEXITED(status) ? WEXITSTATUS(status) : -1;
if (exit_code != 0) {
spdlog::warn("external command failed (exit code {}): {}", exit_code, fmt::join(argv, " "));
}
return {exit_code, output};
}
src/process.h
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// Copyright (C) 2026 Viorel Munteanu
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#pragma once
#include <string>
#include <vector>
struct ProcessResult {
int exit_code;
std::string stdout_output;
};
// Runs argv[0] with the given arguments via fork/execvp, capturing stdout.
// stderr is inherited so the child's own error messages reach the user directly.
ProcessResult run_process(const std::vector<std::string>& argv);
subprojects/spdlog.wrap
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[wrap-file]
directory = spdlog-1.17.0
source_url = https://github.com/gabime/spdlog/archive/refs/tags/v1.17.0.tar.gz
source_filename = spdlog-1.17.0.tar.gz
source_hash = d8862955c6d74e5846b3f580b1605d2428b11d97a410d86e2fb13e857cd3a744
source_fallback_url = https://wrapdb.mesonbuild.com/v2/spdlog_1.17.0-2/get_source/spdlog-1.17.0.tar.gz
patch_filename = spdlog_1.17.0-2_patch.zip
patch_url = https://wrapdb.mesonbuild.com/v2/spdlog_1.17.0-2/get_patch
patch_fallback_url = https://github.com/mesonbuild/wrapdb/releases/download/spdlog_1.17.0-2/spdlog_1.17.0-2_patch.zip
patch_hash = f5dd3aead18a790b5463f1af514eec63d06893d860966771375d77fd4d9e4acf
wrapdb_version = 1.17.0-2
[provide]
dependency_names = spdlog
tests/gen_fixture.py
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#!/usr/bin/env python3
"""Writes a minimal one-layer OCI Image Layout tar to the path given as argv[1].
Used by meson.build to produce a fixture for the `meson test` smoke test.
"""
import gzip
import hashlib
import io
import json
import sys
import tarfile
def sha256_hex(data: bytes) -> str:
return hashlib.sha256(data).hexdigest()
def add_bytes(tar: tarfile.TarFile, name: str, data: bytes) -> None:
info = tarfile.TarInfo(name=name)
info.size = len(data)
tar.addfile(info, io.BytesIO(data))
def main() -> None:
out_path = sys.argv[1]
# Uncompressed layer content: a tiny tar with a single file.
layer_tar_buf = io.BytesIO()
with tarfile.open(fileobj=layer_tar_buf, mode="w") as layer_tar:
add_bytes(layer_tar, "hello.txt", b"hello from slocker-lite fixture\n")
layer_tar_bytes = layer_tar_buf.getvalue()
diff_id = sha256_hex(layer_tar_bytes)
layer_gz_bytes = gzip.compress(layer_tar_bytes)
layer_digest = sha256_hex(layer_gz_bytes)
config = {
"architecture": "amd64",
"os": "linux",
"config": {},
"rootfs": {"type": "layers", "diff_ids": [f"sha256:{diff_id}"]},
}
config_bytes = json.dumps(config).encode()
config_digest = sha256_hex(config_bytes)
manifest = {
"schemaVersion": 2,
"mediaType": "application/vnd.oci.image.manifest.v1+json",
"config": {
"mediaType": "application/vnd.oci.image.config.v1+json",
"digest": f"sha256:{config_digest}",
"size": len(config_bytes),
},
"layers": [
{
"mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
"digest": f"sha256:{layer_digest}",
"size": len(layer_gz_bytes),
}
],
}
manifest_bytes = json.dumps(manifest).encode()
manifest_digest = sha256_hex(manifest_bytes)
index = {
"schemaVersion": 2,
"manifests": [
{
"mediaType": "application/vnd.oci.image.manifest.v1+json",
"digest": f"sha256:{manifest_digest}",
"size": len(manifest_bytes),
}
],
}
index_bytes = json.dumps(index).encode()
oci_layout_bytes = json.dumps({"imageLayoutVersion": "1.0.0"}).encode()
with tarfile.open(out_path, mode="w") as tar:
add_bytes(tar, "oci-layout", oci_layout_bytes)
add_bytes(tar, "index.json", index_bytes)
add_bytes(tar, f"blobs/sha256/{config_digest}", config_bytes)
add_bytes(tar, f"blobs/sha256/{manifest_digest}", manifest_bytes)
add_bytes(tar, f"blobs/sha256/{layer_digest}", layer_gz_bytes)
if __name__ == "__main__":
main()