ci: build minimal and standard images (#135)

Build images without barman-cloud, to be used with backup plugins.

Other changes:

- Implement timestamp-based versioning for images
- Simplify build workflows for enhanced local testing and contribution
- Adopt OCI annotations and generate SBOMs for improved transparency

Closes #132

Signed-off-by: Francesco Canovai <francesco.canovai@enterprisedb.com>
Signed-off-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>
Signed-off-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
Signed-off-by: Niccolò Fei <niccolo.fei@enterprisedb.com>
Co-authored-by: Gabriele Bartolini <gabriele.bartolini@enterprisedb.com>
Co-authored-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
Co-authored-by: Niccolò Fei <niccolo.fei@enterprisedb.com>

docker-bake.hcl

@@ -0,0 +1,109 @@
+variable "environment" {
+  default = "testing"
+  validation {
+    condition = contains(["testing", "production"], environment)
+    error_message = "environment must be either testing or production"
+  }
+}
+
+variable "registry" {
+  default = "localhost:5000"
+}
+
+// Use the revision variable to identify the commit that generated the image
+variable "revision" {
+  default = ""
+}
+
+fullname = ( environment == "testing") ? "${registry}/postgresql-testing" : "{registry}/postgresql"
+now = timestamp()
+authors = "The CloudNativePG Contributors"
+url = "https://github.com/cloudnative-pg/postgres-containers"
+
+target "default" {
+  matrix = {
+    tgt = [
+      "minimal",
+      "standard"
+    ]
+    pgVersion = [
+      "13.18",
+      "14.15",
+      "15.10",
+      "16.6",
+      "17.2"
+    ]
+    base = [
+      // renovate: datasource=docker versioning=loose
+      "debian:bookworm-slim@sha256:d365f4920711a9074c4bcd178e8f457ee59250426441ab2a5f8106ed8fe948eb",
+      // renovate: datasource=docker versioning=loose
+      "debian:bullseye-slim@sha256:b0c91cc181796d34c53f7ea106fbcddaf87f3e601cc371af6a24a019a489c980"
+    ]
+  }
+  platforms = [
+    "linux/amd64",
+    "linux/arm64"
+  ]
+  dockerfile = "Dockerfile"
+  name = "postgresql-${index(split(".",pgVersion),0)}-${tgt}-${distroVersion(base)}"
+  tags = [
+    "${fullname}:${index(split(".",pgVersion),0)}-${tgt}-${distroVersion(base)}",
+    "${fullname}:${pgVersion}-${tgt}-${distroVersion(base)}",
+    "${fullname}:${pgVersion}-${formatdate("YYYYMMDDhhmm", now)}-${tgt}-${distroVersion(base)}"
+  ]
+  context = "."
+  target = "${tgt}"
+  args = {
+    PG_VERSION = "${pgVersion}"
+    BASE = "${base}"
+  }
+  attest = [
+    "type=provenance,mode=max",
+    "type=sbom"
+  ]
+  annotations = [
+    "index,manifest:org.opencontainers.image.created=${now}",
+    "index,manifest:org.opencontainers.image.url=${url}",
+    "index,manifest:org.opencontainers.image.source=${url}",
+    "index,manifest:org.opencontainers.image.version=${pgVersion}",
+    "index,manifest:org.opencontainers.image.revision=${revision}",
+    "index,manifest:org.opencontainers.image.vendor=${authors}",
+    "index,manifest:org.opencontainers.image.title=CloudNativePG PostgreSQL ${pgVersion} ${tgt}",
+    "index,manifest:org.opencontainers.image.description=A ${tgt} PostgreSQL ${pgVersion} container image",
+    "index,manifest:org.opencontainers.image.documentation=https://github.com/cloudnative-pg/postgres-containers",
+    "index,manifest:org.opencontainers.image.authors=${authors}",
+    "index,manifest:org.opencontainers.image.licenses=Apache-2.0",
+    "index,manifest:org.opencontainers.image.base.name=docker.io/library/${tag(base)}",
+    "index,manifest:org.opencontainers.image.base.digest=${digest(base)}"
+  ]
+  labels = {
+    "org.opencontainers.image.created" = "${now}",
+    "org.opencontainers.image.url" = "${url}",
+    "org.opencontainers.image.source" = "${url}",
+    "org.opencontainers.image.version" = "${pgVersion}",
+    "org.opencontainers.image.revision" = "${revision}",
+    "org.opencontainers.image.vendor" = "${authors}",
+    "org.opencontainers.image.title" = "CloudNativePG PostgreSQL ${pgVersion} ${tgt}",
+    "org.opencontainers.image.description" = "A ${tgt} PostgreSQL ${pgVersion} container image",
+    "org.opencontainers.image.documentation" = "${url}",
+    "org.opencontainers.image.authors" = "${authors}",
+    "org.opencontainers.image.licenses" = "Apache-2.0"
+    "org.opencontainers.image.base.name" = "docker.io/library/debian:${tag(base)}"
+    "org.opencontainers.image.base.digest" = "${digest(base)}"
+  }
+}
+
+function tag {
+  params = [ imageNameWithSha ]
+  result = index(split("@", index(split(":", imageNameWithSha), 1)), 0)
+}
+
+function distroVersion {
+  params = [ imageNameWithSha ]
+  result = index(split("-", tag(imageNameWithSha)), 0)
+}
+
+function digest {
+  params = [ imageNameWithSha ]
+  result = index(split("@", imageNameWithSha), 1)
+}