github.com/Ilhicas/nomad@v1.0.4-0.20210304152020-e86851182bc3/helper/pluginutils/hclutils/util.go (about)

     1  package hclutils
     2  
     3  import (
     4  	"bytes"
     5  	"errors"
     6  	"fmt"
     7  
     8  	"github.com/hashicorp/go-msgpack/codec"
     9  	hcl "github.com/hashicorp/hcl/v2"
    10  	"github.com/hashicorp/hcl/v2/hcldec"
    11  	hjson "github.com/hashicorp/hcl/v2/json"
    12  	"github.com/hashicorp/nomad/nomad/structs"
    13  	"github.com/zclconf/go-cty/cty"
    14  	"github.com/zclconf/go-cty/cty/function"
    15  	"github.com/zclconf/go-cty/cty/function/stdlib"
    16  )
    17  
    18  // ParseHclInterface is used to convert an interface value representing a hcl2
    19  // body and return the interpolated value. Vars may be nil if there are no
    20  // variables to interpolate.
    21  func ParseHclInterface(val interface{}, spec hcldec.Spec, vars map[string]cty.Value) (cty.Value, hcl.Diagnostics, []error) {
    22  	evalCtx := &hcl.EvalContext{
    23  		Variables: vars,
    24  		Functions: GetStdlibFuncs(),
    25  	}
    26  
    27  	// Encode to json
    28  	var buf bytes.Buffer
    29  	enc := codec.NewEncoder(&buf, structs.JsonHandle)
    30  	err := enc.Encode(val)
    31  	if err != nil {
    32  		// Convert to a hcl diagnostics message
    33  		errorMessage := fmt.Sprintf("Label encoding failed: %v", err)
    34  		return cty.NilVal,
    35  			hcl.Diagnostics([]*hcl.Diagnostic{{
    36  				Severity: hcl.DiagError,
    37  				Summary:  "Failed to encode label value",
    38  				Detail:   errorMessage,
    39  			}}),
    40  			[]error{errors.New(errorMessage)}
    41  	}
    42  
    43  	// Parse the json as hcl2
    44  	hclFile, diag := hjson.Parse(buf.Bytes(), "")
    45  	if diag.HasErrors() {
    46  		return cty.NilVal, diag, formattedDiagnosticErrors(diag)
    47  	}
    48  
    49  	value, decDiag := hcldec.Decode(hclFile.Body, spec, evalCtx)
    50  	diag = diag.Extend(decDiag)
    51  	if diag.HasErrors() {
    52  		return cty.NilVal, diag, formattedDiagnosticErrors(diag)
    53  	}
    54  
    55  	return value, diag, nil
    56  }
    57  
    58  // GetStdlibFuncs returns the set of stdlib functions.
    59  func GetStdlibFuncs() map[string]function.Function {
    60  	return map[string]function.Function{
    61  		"abs":        stdlib.AbsoluteFunc,
    62  		"coalesce":   stdlib.CoalesceFunc,
    63  		"concat":     stdlib.ConcatFunc,
    64  		"hasindex":   stdlib.HasIndexFunc,
    65  		"int":        stdlib.IntFunc,
    66  		"jsondecode": stdlib.JSONDecodeFunc,
    67  		"jsonencode": stdlib.JSONEncodeFunc,
    68  		"length":     stdlib.LengthFunc,
    69  		"lower":      stdlib.LowerFunc,
    70  		"max":        stdlib.MaxFunc,
    71  		"min":        stdlib.MinFunc,
    72  		"reverse":    stdlib.ReverseFunc,
    73  		"strlen":     stdlib.StrlenFunc,
    74  		"substr":     stdlib.SubstrFunc,
    75  		"upper":      stdlib.UpperFunc,
    76  	}
    77  }
    78  
    79  // TODO: update hcl2 library with better diagnostics formatting for streamed configs
    80  // - should be arbitrary labels not JSON https://github.com/hashicorp/hcl2/blob/4fba5e1a75e382aed7f7a7993f2c4836a5e1cd52/hcl/json/structure.go#L66
    81  // - should not print diagnostic subject https://github.com/hashicorp/hcl2/blob/4fba5e1a75e382aed7f7a7993f2c4836a5e1cd52/hcl/diagnostic.go#L77
    82  func formattedDiagnosticErrors(diag hcl.Diagnostics) []error {
    83  	var errs []error
    84  	for _, d := range diag {
    85  		if d.Summary == "Extraneous JSON object property" {
    86  			d.Summary = "Invalid label"
    87  		}
    88  		err := fmt.Errorf("%s: %s", d.Summary, d.Detail)
    89  		errs = append(errs, err)
    90  	}
    91  	return errs
    92  }