Add build-arg and build-context options

README.md

@@ -50,9 +50,27 @@ Skipper can serve as your primary tool for your daily development tasks:
   --build-container-tag         Tag of the build container
   --build-container-net         Network to connect the build container (default: net=host)
   --env-file                    Environment variables file/s to pass to the container
+  --build-arg                   Set build-time variables for the container
+  --build-context               Additional build contexts when running the build command, give them a name, and then access them inside a Dockerfile
   --help                        Show this message and exit.
 ```
 
+### [Build context explained](https://www.docker.com/blog/dockerfiles-now-support-multiple-build-contexts/)
+Skipper allows you to add additional build contexts when running the build command, give them a name, and then access them inside a Dockerfile.
+The build context can be one of the following:
+* Local directory – e.g. `--build-context project2=../path/to/project2/src`
+* Git repository – e.g. `--build-context qemu-src=https://github.com/qemu/qemu.git`
+* HTTP URL to a tarball – e.g. `--build-context src=https://example.org/releases/src.tar`
+* Docker image – Define with a `docker-image://` prefix, e.g. `--build-context alpine=docker-image://alpine:3.15`
+
+On the Dockerfile side, you can reference the build context on all commands that accept the “from” parameter. Here’s how that might look:
+
+```dockerfile
+FROM [name]
+COPY --from=[name] ...
+RUN --mount=from=[name] …
+```
+
 ### Build
 As a convention, skipper infers the docker images from the Dockerfiles in the top directory of your repository. For example, assuming that there are 3 Dockerfile in the top directory of the repository:
 ```
@@ -154,6 +172,16 @@ build-container-image: development
 build-container-tag: latest
 container-context: /path/to/context/dir
 
+build-arg:
+  - VAR1=value1
+  - VAR2=value2
+
+build-context:
+  - context1=/path/to/context/dir # Local directory
+  - qemu-src=https://github.com/qemu/qemu.git # Remote git repository
+  - src=https://example.org/releases/src.tar # Remote tar file
+  - alpine=docker-image://alpine:3.15 # Remote docker image
+
 make: 
     makefile: Makefile.arm32
 containers:
@@ -164,6 +192,14 @@ env:
 env_file: path/to/env_file.env
 ```
 
+```yaml
+# Use the git revision as the build container tag
+# Allows to use the same build container unless the git revision changes
+# This is useful when using a CI system that caches the build container
+# Remember to commit if you changing the build container
+build-container-tag: 'git:revision'
+```
+
 Using the above configuration file, we now can run a simplified version of the make command described above:
 ```bash
 skipper make tests

requirements.txt

@@ -1,5 +1,5 @@
 PyYAML>=3.11
-click==6.7
+click>=6.7
 requests>=2.6.0
 tabulate>=0.7.5
 six>=1.10.0

setup.cfg

@@ -1,15 +1,15 @@
 [metadata]
 name = strato-skipper
 author = Adir Gabai
-author-email = [email protected]
-home-page = http://github.com/Stratoscale/skipper
+author_email = [email protected]
+home_page = http://github.com/Stratoscale/skipper
 summary = Easily dockerize your Git repository
 license = Apache-2
 long_description = file: README.md
 long_description_content_type = text/markdown
 
-requires-dist = setuptools
-requires-python = >=3
+requires_dist = setuptools
+requires_python = >=3
 
 
 [files]
@@ -21,4 +21,4 @@ console_scripts =
     skipper = skipper.main:main
 
 [pep8]
-max-line-length=145
+max_line_length=145

skipper.yaml

@@ -1 +1 @@
-build-container-image: skipper-build
+build-container-image: skipper-build

skipper/builder.py

@@ -0,0 +1,192 @@
+from dataclasses import dataclass
+from logging import Logger
+from typing import Callable
+
+from skipper import utils
+
+DOCKER_TAG_FOR_CACHE = "cache"
+
+
+class Image:
+    """
+    A class to represent an image with attributes like registry, name, tag, namespace.
+    """
+
+    def __init__(self, name, tag, dockerfile=None, registry=None, namespace=None):
+        """
+        Constructs all the necessary attributes for the Image object.
+
+        :param registry: Registry for the image
+        :param name: Name of the image
+        :param tag: Tag for the image
+        :param namespace: Namespace for the registry
+        """
+        if not name:
+            raise ValueError("Image name is required")
+
+        self.name = name
+        self.tag = tag
+        self.registry = registry
+        self.namespace = namespace
+        self.__dockerfile = dockerfile
+        self.__cache_fqdn = None
+        self.__fqdn = None
+
+    def __str__(self):
+        return self.fqdn
+
+    @property
+    def local(self):
+        """
+        Creates a string that represents the local image.
+
+        :return: Image in name:tag format
+        """
+        if self.tag:
+            return self.name + ":" + self.tag
+        return self.name
+
+    @property
+    def cache_fqdn(self):
+        """
+        Generates a Fully Qualified Domain Name for the cached image.
+
+        :return: Cached image Fully Qualified Domain Name
+        """
+        if not self.__cache_fqdn:
+            self.__cache_fqdn = utils.generate_fqdn_image(
+                self.registry, self.namespace, self.name, DOCKER_TAG_FOR_CACHE
+            )
+        return self.__cache_fqdn
+
+    @property
+    def fqdn(self):
+        """
+        Generates a Fully Qualified Domain Name for the image.
+
+        :return: image Fully Qualified Domain Name
+        """
+        if not self.__fqdn:
+            self.__fqdn = utils.generate_fqdn_image(
+                self.registry, self.namespace, self.name, self.tag
+            )
+        return self.__fqdn
+
+    @property
+    def dockerfile(self):
+        """
+        Returns the Dockerfile for the image.
+
+        :return: Dockerfile for the image
+        """
+        if not self.__dockerfile:
+            self.__dockerfile = utils.image_to_dockerfile(self.name)
+        return self.__dockerfile
+
+    @classmethod
+    def from_context_obj(cls, ctx_obj):
+        """
+        Creates an instance of Image from a given context.
+
+        :param ctx_obj: Click context object
+        :return: An instance of Image
+        """
+        if ctx_obj is None:
+            return None
+
+        return cls(
+            name=ctx_obj.get("build_container_image"),
+            tag=ctx_obj.get("build_container_tag"),
+            registry=ctx_obj.get("registry"),
+        )
+
+
+@dataclass
+class BuildOptions:
+    """
+    A class to encapsulate all the build options needed to create Docker image.
+    """
+
+    def __init__(
+        self,
+        image: Image,
+        container_context,
+        build_contexts=None,
+        build_args=None,
+        use_cache=False,
+    ):
+        """
+        Constructs all the necessary attributes for the build options.
+
+        :param image: image details as an instance of Image
+        :param container_context: Context for the build
+        :param build_contexts: Build contexts to add to build
+        :param build_args: Arguments to pass to build
+        :param use_cache: Boolean indicating if cache should be used
+        """
+        self.image = image
+        self.container_context = container_context
+        self.build_contexts = [ctx for ctx in build_contexts if ctx] if build_contexts else []
+        self.build_args = [arg for arg in build_args if arg] if build_args else []
+        self.use_cache = use_cache
+
+    @classmethod
+    def from_context_obj(cls, ctx_obj):
+        """
+        Creates an instance of BuildOptions from a given context.
+
+        :param ctx_obj: Click context object
+        :return: An instance of BuildOptions
+        """
+        if ctx_obj is None:
+            return None
+
+        return cls(
+            image=Image.from_context_obj(ctx_obj),
+            container_context=ctx_obj.get("container_context"),
+            build_contexts=ctx_obj.get("build_contexts"),
+            build_args=ctx_obj.get("build_args"),
+            use_cache=ctx_obj.get("use_cache"),
+        )
+
+
+def build(options: BuildOptions, runner: Callable, logger: Logger) -> int:
+    """
+    Builds a image based on given build options and runner function.
+
+    :param options: Build options as an instance of BuildOptions
+    :param runner: Callable that runs the Docker commands
+    :param logger: Logger instance
+    :return: A return code representing the success or failure of the build
+    """
+    cmd = ["build", "--network=host"]
+
+    for arg in options.build_args:
+        cmd += ["--build-arg", arg]
+
+    for build_ctx in options.build_contexts:
+        cmd += ["--build-context", build_ctx]
+
+    cmd += [
+        "-f",
+        options.image.dockerfile,
+        "-t",
+        options.image.local,
+        options.container_context or ".",
+    ]
+
+    if options.use_cache:
+        runner(["pull", options.image.cache_fqdn])
+        cmd.extend(["--cache-from", options.image.cache_fqdn])
+
+    ret = runner(cmd)
+
+    if ret != 0:
+        logger.error("Failed to build image: %s", options.image)
+        return ret
+
+    if options.use_cache:
+        runner(["tag", options.image.name, options.image.cache_fqdn])
+        runner(["push", options.image.cache_fqdn])
+
+    return 0