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// Copyright 2023 The CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package load_test
import (
"fmt"
"os"
"path/filepath"
"golang.org/x/tools/txtar"
"cuelang.org/go/cue"
"cuelang.org/go/cue/cuecontext"
"cuelang.org/go/cue/load"
"cuelang.org/go/mod/modregistrytest"
)
// Note that these examples may not be runnable on pkg.go.dev,
// as they expect files to be present inside testdata.
// Using cue/load with real files on disk keeps the example realistic
// and enables the user to easily tweak the code to their needs.
func Example() {
// Load the package "example" relative to the directory testdata/testmod.
// Akin to loading via: cd testdata/testmod && cue export ./example
insts := load.Instances([]string{"./example"}, &load.Config{
Dir: filepath.Join("testdata", "testmod"),
Env: []string{}, // or nil to use os.Environ
})
// testdata/testmod/example just has one file without any build tags,
// so we get a single instance as a result.
fmt.Println("Number of instances:", len(insts))
inst := insts[0]
if err := inst.Err; err != nil {
fmt.Println(err)
return
}
fmt.Println("Instance module:", inst.Module)
fmt.Println("Instance import path:", inst.ImportPath)
fmt.Println()
// Inspect the syntax trees.
fmt.Println("Source files:")
for _, file := range inst.Files {
fmt.Println(filepath.Base(file.Filename), "with", len(file.Decls), "declarations")
}
fmt.Println()
// Build the instance into a value.
// We can also use BuildInstances for many instances at once.
ctx := cuecontext.New()
val := ctx.BuildInstance(inst)
if err := val.Err(); err != nil {
fmt.Println(err)
return
}
// Inspect the contents of the value, such as one string field.
fieldStr, err := val.LookupPath(cue.MakePath(cue.Str("output"))).String()
if err != nil {
fmt.Println(err)
return
}
fmt.Println("Field string:", fieldStr)
// Output:
// Number of instances: 1
// Instance module: mod.test/test@v0
// Instance import path: mod.test/test/example@v0
//
// Source files:
// example.cue with 3 declarations
//
// Field string: Hello Joe
}
func Example_externalModules() {
// setUpModulesExample starts a temporary in-memory registry,
// populates it with an example module, and sets CUE_REGISTRY to refer to it.
// Users can leave [load.Config.Env] empty to use the default registry,
// or set one globally with os.Setenv("CUE_REGISTRY", "registry.myorg.com").
env, cleanup := setUpModulesExample()
defer cleanup()
insts := load.Instances([]string{"."}, &load.Config{
Dir: filepath.Join("testdata", "testmod-external"),
Env: env, // or nil to use os.Environ
})
inst := insts[0]
if err := inst.Err; err != nil {
fmt.Println(err)
return
}
ctx := cuecontext.New()
val := ctx.BuildInstance(inst)
if err := val.Err(); err != nil {
fmt.Println(err)
return
}
// Inspect the contents of the value, such as one string field.
fieldStr, err := val.LookupPath(cue.MakePath(cue.Str("output"))).String()
if err != nil {
fmt.Println(err)
return
}
fmt.Println("Field string:", fieldStr)
// Output:
// Field string: hello, world
}
func setUpModulesExample() (env []string, cleanup func()) {
registryFS, err := txtar.FS(txtar.Parse([]byte(`
-- foo.example_v0.0.1/cue.mod/module.cue --
module: "foo.example@v0"
language: version: "v0.8.0"
-- foo.example_v0.0.1/bar/bar.cue --
package bar
value: "world"
`)))
if err != nil {
panic(err)
}
registry, err := modregistrytest.New(registryFS, "")
if err != nil {
panic(err)
}
env = append(env, "CUE_REGISTRY="+registry.Host()+"+insecure")
// We also set up a temporary cache directory to fetch and extract modules into.
dir, err := os.MkdirTemp("", "")
if err != nil {
panic(err)
}
env = append(env, "CUE_CACHE_DIR="+dir)
return env, registry.Close
}
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