cue/load: add support for build tags
Fixes #511
Change-Id: I012286cffe357ab7d835ef35e0f5e2ece00b9b89
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/7064
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cmd/cue/cmd/help.go b/cmd/cue/cmd/help.go
index 51ab0c0..91f3ac3 100644
--- a/cmd/cue/cmd/help.go
+++ b/cmd/cue/cmd/help.go
@@ -262,9 +262,32 @@
var injectHelp = &cobra.Command{
Use: "injection",
- Short: "inject values from the command line",
- Long: `Many of the cue commands allow injecting values
-from the command line using the --inject/-t flag.
+ Short: "inject files or values into specific fields for a build",
+ Long: `Many of the cue commands allow injecting values or
+selecting files from the command line using the --inject/-t flag.
+
+
+Injecting files
+
+A "build" attribute defines a boolean expression that causes a file
+to only be included in a build if its expression evaluates to true.
+There may only be a single @if attribute per file and it must
+appear before a package clause.
+
+The expression is a subset of CUE consisting only of identifiers
+and the operators &&, ||, !, where identifiers refer to tags
+defined by the user on the command line.
+
+For example, the following file will only be included in a build
+if the user includes the flag "-t prod" on the command line.
+
+ // File prod.cue
+ @if(prod)
+
+ package foo
+
+
+Injecting values
The injection mechanism allows values to be injected into fields
that are marked with a "tag" attribute. For any field of the form
diff --git a/cue/load/config.go b/cue/load/config.go
index d32f080..88b6a75 100644
--- a/cue/load/config.go
+++ b/cue/load/config.go
@@ -163,6 +163,16 @@
// build and to inject values into the AST.
//
//
+ // File selection
+ //
+ // Files with an attribute of the form @if(expr) before a package clause
+ // are conditionally included if expr resolves to true, where expr refers to
+ // boolean values in Tags.
+ //
+ // It is an error for a file to have more than one @if attribute or to
+ // have a @if attribute without or after a package clause.
+ //
+ //
// Value injection
//
// The Tags values are also used to inject values into fields with a
@@ -490,7 +500,10 @@
}
}
- c.loader = &loader{cfg: &c}
+ c.loader = &loader{
+ cfg: &c,
+ buildTags: make(map[string]bool),
+ }
// TODO: also make this work if run from outside the module?
switch {
diff --git a/cue/load/import.go b/cue/load/import.go
index 6ee6084..bc286a3 100644
--- a/cue/load/import.go
+++ b/cue/load/import.go
@@ -375,6 +375,15 @@
return false // don't mark as added
}
+ if include, err := shouldBuildFile(pf, fp); !include {
+ if err != nil {
+ fp.err = errors.Append(fp.err, err)
+ }
+ p.IgnoredCUEFiles = append(p.InvalidCUEFiles, fullPath)
+ p.IgnoredFiles = append(p.InvalidFiles, file)
+ return false
+ }
+
if pkg != "" && pkg != "_" {
if p.PkgName == "" {
p.PkgName = pkg
diff --git a/cue/load/loader.go b/cue/load/loader.go
index da5a590..61fa06c 100644
--- a/cue/load/loader.go
+++ b/cue/load/loader.go
@@ -86,7 +86,7 @@
// TODO(api): have API call that returns an error which is the aggregate
// of all build errors. Certain errors, like these, hold across builds.
- if err := injectTags(c.Tags, l.tags); err != nil {
+ if err := injectTags(c.Tags, l); err != nil {
for _, p := range a {
p.ReportError(err)
}
@@ -110,9 +110,10 @@
)
type loader struct {
- cfg *Config
- stk importStack
- tags []tag // tags found in files
+ cfg *Config
+ stk importStack
+ tags []tag // tags found in files
+ buildTags map[string]bool
}
func (l *loader) abs(filename string) string {
diff --git a/cue/load/loader_test.go b/cue/load/loader_test.go
index 073b45c..17177fe 100644
--- a/cue/load/loader_test.go
+++ b/cue/load/loader_test.go
@@ -253,6 +253,47 @@
root: $CWD/testdata
dir: $CWD/testdata/toolonly
display:./toolonly`,
+ }, {
+ cfg: &Config{
+ Dir: testdataDir,
+ Tags: []string{"prod"},
+ },
+ args: args("./tags"),
+ want: `
+path: example.org/test/tags
+module: example.org/test
+root: $CWD/testdata
+dir: $CWD/testdata/tags
+display:./tags
+files:
+ $CWD/testdata/tags/prod.cue`,
+ }, {
+ cfg: &Config{
+ Dir: testdataDir,
+ Tags: []string{"prod", "foo=bar"},
+ },
+ args: args("./tags"),
+ want: `
+path: example.org/test/tags
+module: example.org/test
+root: $CWD/testdata
+dir: $CWD/testdata/tags
+display:./tags
+files:
+ $CWD/testdata/tags/prod.cue`,
+ }, {
+ cfg: &Config{
+ Dir: testdataDir,
+ Tags: []string{"prod"},
+ },
+ args: args("./tagsbad"),
+ want: `
+err: multiple @if attributes (and 2 more errors)
+path: example.org/test/tagsbad
+module: example.org/test
+root: $CWD/testdata
+dir: $CWD/testdata/tagsbad
+display:./tagsbad`,
}}
for i, tc := range testCases {
t.Run(strconv.Itoa(i)+"/"+strings.Join(tc.args, ":"), func(t *testing.T) {
diff --git a/cue/load/tags.go b/cue/load/tags.go
index fad4d48..d30b502 100644
--- a/cue/load/tags.go
+++ b/cue/load/tags.go
@@ -21,6 +21,7 @@
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/build"
"cuelang.org/go/cue/errors"
+ "cuelang.org/go/cue/parser"
"cuelang.org/go/cue/token"
"cuelang.org/go/internal"
"cuelang.org/go/internal/cli"
@@ -138,13 +139,13 @@
return tags, errs
}
-func injectTags(tags []string, a []tag) errors.Error {
+func injectTags(tags []string, l *loader) errors.Error {
// Parses command line args
for _, s := range tags {
p := strings.Index(s, "=")
- found := false
+ found := l.buildTags[s]
if p > 0 { // key-value
- for _, t := range a {
+ for _, t := range l.tags {
if t.key == s[:p] {
found = true
if err := t.inject(s[p+1:]); err != nil {
@@ -156,7 +157,7 @@
return errors.Newf(token.NoPos, "no tag for %q", s[:p])
}
} else { // shorthand
- for _, t := range a {
+ for _, t := range l.tags {
for _, sh := range t.shorthands {
if sh == s {
found = true
@@ -167,9 +168,104 @@
}
}
if !found {
- return errors.Newf(token.NoPos, "no shorthand for %q", s)
+ return errors.Newf(token.NoPos, "tag %q not used in any file", s)
}
}
}
return nil
}
+
+func shouldBuildFile(f *ast.File, fp *fileProcessor) (bool, errors.Error) {
+ tags := fp.c.Tags
+
+ a, errs := getBuildAttr(f)
+ if errs != nil {
+ return false, errs
+ }
+ if a == nil {
+ return true, nil
+ }
+
+ _, body := a.Split()
+
+ expr, err := parser.ParseExpr("", body)
+ if err != nil {
+ return false, errors.Promote(err, "")
+ }
+
+ tagMap := map[string]bool{}
+ for _, t := range tags {
+ tagMap[t] = !strings.ContainsRune(t, '=')
+ }
+
+ c := checker{tags: tagMap, loader: fp.c.loader}
+ include := c.shouldInclude(expr)
+ if c.err != nil {
+ return false, c.err
+ }
+ return include, nil
+}
+
+func getBuildAttr(f *ast.File) (*ast.Attribute, errors.Error) {
+ var a *ast.Attribute
+ for _, d := range f.Decls {
+ switch x := d.(type) {
+ case *ast.Attribute:
+ key, _ := x.Split()
+ if key != "if" {
+ continue
+ }
+ if a != nil {
+ err := errors.Newf(d.Pos(), "multiple @if attributes")
+ err = errors.Append(err,
+ errors.Newf(a.Pos(), "previous declaration here"))
+ return nil, err
+ }
+ a = x
+
+ case *ast.Package:
+ break
+ }
+ }
+ return a, nil
+}
+
+type checker struct {
+ loader *loader
+ tags map[string]bool
+ err errors.Error
+}
+
+func (c *checker) shouldInclude(expr ast.Expr) bool {
+ switch x := expr.(type) {
+ case *ast.Ident:
+ c.loader.buildTags[x.Name] = true
+ return c.tags[x.Name]
+
+ case *ast.BinaryExpr:
+ switch x.Op {
+ case token.LAND:
+ return c.shouldInclude(x.X) && c.shouldInclude(x.Y)
+
+ case token.LOR:
+ return c.shouldInclude(x.X) || c.shouldInclude(x.Y)
+
+ default:
+ c.err = errors.Append(c.err, errors.Newf(token.NoPos,
+ "invalid operator %v", x.Op))
+ return false
+ }
+
+ case *ast.UnaryExpr:
+ if x.Op != token.NOT {
+ c.err = errors.Append(c.err, errors.Newf(token.NoPos,
+ "invalid operator %v", x.Op))
+ }
+ return !c.shouldInclude(x.X)
+
+ default:
+ c.err = errors.Append(c.err, errors.Newf(token.NoPos,
+ "invalid type %T in build attribute", expr))
+ return false
+ }
+}
diff --git a/cue/load/testdata/tags/prod.cue b/cue/load/testdata/tags/prod.cue
new file mode 100644
index 0000000..ce61d47
--- /dev/null
+++ b/cue/load/testdata/tags/prod.cue
@@ -0,0 +1,5 @@
+@if(prod)
+
+package tags
+
+foo: string @tag(foo)
diff --git a/cue/load/testdata/tags/stage.cue b/cue/load/testdata/tags/stage.cue
new file mode 100644
index 0000000..2d72a68
--- /dev/null
+++ b/cue/load/testdata/tags/stage.cue
@@ -0,0 +1,3 @@
+@if(stage)
+
+package tags
diff --git a/cue/load/testdata/tagsbad/prod.cue b/cue/load/testdata/tagsbad/prod.cue
new file mode 100644
index 0000000..f0598d9
--- /dev/null
+++ b/cue/load/testdata/tagsbad/prod.cue
@@ -0,0 +1,4 @@
+@if(foo)
+@if(bar)
+
+package tagsbad
diff --git a/cue/load/testdata/tagsbad/stage.cue b/cue/load/testdata/tagsbad/stage.cue
new file mode 100644
index 0000000..45af3ad
--- /dev/null
+++ b/cue/load/testdata/tagsbad/stage.cue
@@ -0,0 +1,3 @@
+package tagsbad
+
+@if(prod)
