|
| 1 | +import hashlib |
| 2 | +import json |
| 3 | +import os |
| 4 | +import shutil |
| 5 | +from typing import Dict, List, Optional |
| 6 | + |
| 7 | +from typing_extensions import TypedDict |
| 8 | + |
| 9 | + |
| 10 | +class BuildContext(TypedDict, total=False): |
| 11 | + """ |
| 12 | + Build context for custom BYOD image builds. |
| 13 | +
|
| 14 | + Attributes: |
| 15 | + envs: Environment variables to set in the image. |
| 16 | + post_build_script: Filename of the post-build script. |
| 17 | + post_build_script_digest: SHA256 digest of the post-build script. |
| 18 | + python_depset: Filename of the Python dependencies lock file. |
| 19 | + python_depset_digest: SHA256 digest of the Python dependencies lock file. |
| 20 | + """ |
| 21 | + |
| 22 | + envs: Dict[str, str] |
| 23 | + |
| 24 | + post_build_script: str |
| 25 | + post_build_script_digest: str |
| 26 | + |
| 27 | + python_depset: str |
| 28 | + python_depset_digest: str |
| 29 | + |
| 30 | + |
| 31 | +def make_build_context( |
| 32 | + base_dir: str, |
| 33 | + envs: Optional[Dict[str, str]] = None, |
| 34 | + post_build_script: Optional[str] = None, |
| 35 | + python_depset: Optional[str] = None, |
| 36 | +) -> BuildContext: |
| 37 | + """ |
| 38 | + Create a BuildContext with computed file digests. |
| 39 | +
|
| 40 | + Args: |
| 41 | + base_dir: Directory containing the source files. |
| 42 | + envs: Environment variables to set in the image. |
| 43 | + post_build_script: Filename of the post-build script. |
| 44 | + python_depset: Filename of the Python dependencies lock file. |
| 45 | +
|
| 46 | + Returns: |
| 47 | + A BuildContext with filenames and their SHA256 digests. |
| 48 | + """ |
| 49 | + ctx: BuildContext = {} |
| 50 | + |
| 51 | + if envs: |
| 52 | + ctx["envs"] = envs |
| 53 | + |
| 54 | + if post_build_script: |
| 55 | + ctx["post_build_script"] = post_build_script |
| 56 | + path = os.path.join(base_dir, post_build_script) |
| 57 | + ctx["post_build_script_digest"] = _sha256_file(path) |
| 58 | + |
| 59 | + if python_depset: |
| 60 | + ctx["python_depset"] = python_depset |
| 61 | + path = os.path.join(base_dir, python_depset) |
| 62 | + ctx["python_depset_digest"] = _sha256_file(path) |
| 63 | + |
| 64 | + return ctx |
| 65 | + |
| 66 | + |
| 67 | +def encode_build_context(ctx: BuildContext) -> str: |
| 68 | + """Encode a BuildContext to deterministic minified JSON.""" |
| 69 | + return json.dumps(ctx, sort_keys=True, separators=(",", ":")) |
| 70 | + |
| 71 | + |
| 72 | +def decode_build_context(data: str) -> BuildContext: |
| 73 | + """Decode a JSON string to a BuildContext.""" |
| 74 | + return json.loads(data) |
| 75 | + |
| 76 | + |
| 77 | +def build_context_digest(ctx: BuildContext) -> str: |
| 78 | + """Compute SHA256 digest of the encoded BuildContext.""" |
| 79 | + encoded = encode_build_context(ctx) |
| 80 | + digest = hashlib.sha256(encoded.encode()).hexdigest() |
| 81 | + return f"sha256:{digest}" |
| 82 | + |
| 83 | + |
| 84 | +def fill_build_context_dir( |
| 85 | + ctx: BuildContext, |
| 86 | + build_dir: str, |
| 87 | + source_dir: str, |
| 88 | +) -> None: |
| 89 | + """ |
| 90 | + Generate Dockerfile and copy source files to the build directory. |
| 91 | +
|
| 92 | + Args: |
| 93 | + ctx: The BuildContext specifying what to include. |
| 94 | + build_dir: Target directory for the generated Dockerfile and copied files. |
| 95 | + source_dir: Source directory containing the original files. |
| 96 | + """ |
| 97 | + dockerfile: List[str] = ["# syntax=docker/dockerfile:1.3-labs"] |
| 98 | + dockerfile.append("ARG BASE_IMAGE") |
| 99 | + dockerfile.append("FROM ${BASE_IMAGE}") |
| 100 | + |
| 101 | + if "envs" in ctx and ctx["envs"]: |
| 102 | + dockerfile.append("ENV \\") |
| 103 | + env_lines = [f" {k}={v}" for k, v in sorted(ctx["envs"].items())] |
| 104 | + dockerfile.append(" \\\n".join(env_lines)) |
| 105 | + |
| 106 | + if "python_depset" in ctx: |
| 107 | + shutil.copy( |
| 108 | + os.path.join(source_dir, ctx["python_depset"]), |
| 109 | + os.path.join(build_dir, "python_depset.lock"), |
| 110 | + ) |
| 111 | + shutil.copy( |
| 112 | + os.path.join(source_dir, "install_python_deps.sh"), |
| 113 | + os.path.join(build_dir, "install_python_deps.sh"), |
| 114 | + ) |
| 115 | + dockerfile.append("COPY install_python_deps.sh /tmp/install_python_deps.sh") |
| 116 | + dockerfile.append("COPY python_depset.lock python_depset.lock") |
| 117 | + dockerfile.append("RUN bash /tmp/install_python_deps.sh python_depset.lock") |
| 118 | + |
| 119 | + if "post_build_script" in ctx: |
| 120 | + shutil.copy( |
| 121 | + os.path.join(source_dir, ctx["post_build_script"]), |
| 122 | + os.path.join(build_dir, "post_build_script.sh"), |
| 123 | + ) |
| 124 | + dockerfile.append("COPY post_build_script.sh /tmp/post_build_script.sh") |
| 125 | + dockerfile.append("RUN bash /tmp/post_build_script.sh") |
| 126 | + |
| 127 | + dockerfile_path = os.path.join(build_dir, "Dockerfile") |
| 128 | + with open(dockerfile_path, "w") as f: |
| 129 | + f.write("\n".join(dockerfile) + "\n") |
| 130 | + |
| 131 | + |
| 132 | +def _sha256_file(path: str) -> str: |
| 133 | + with open(path, "rb") as f: |
| 134 | + digest = hashlib.sha256(f.read()).hexdigest() |
| 135 | + return f"sha256:{digest}" |
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