[VPEX][2/8] Add local-env compute-target resolution

libs/localenv/envkey.go

@@ -0,0 +1,85 @@
+package localenv
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// clauseRe splits a single requires-python clause into its operator (optional),
+// MAJOR.MINOR version, and an optional patch component. A clause with no operator
+// is a bare floor. The patch capture (group 4) is needed to interpret a strict
+// ">" correctly: ">3.10" excludes all of 3.10.x, but ">3.10.5" is still satisfied
+// by 3.10.6, so only the former bumps the minor.
+var clauseRe = regexp.MustCompile(`^(>=|<=|===|==|~=|!=|<|>)?\s*(\d+)\.(\d+)(\.\d+)?`)
+
+// NormalizeServerless returns the canonical "vN" spelling of a serverless
+// version accepting "4", "v4", or "V4".
+func NormalizeServerless(version string) string {
+	return "v" + strings.TrimPrefix(strings.ToLower(version), "v")
+}
+
+// EnvKeyForServerless returns the environment key for a serverless version.
+func EnvKeyForServerless(version string) string {
+	return "serverless/serverless-" + NormalizeServerless(version)
+}
+
+// EnvKeyForSparkVersion returns the environment key for a Spark version.
+func EnvKeyForSparkVersion(sparkVersion string) string {
+	return "dbr/" + sparkVersion
+}
+
+// PythonMinorFromRequires parses a PEP 440 requires-python string and returns
+// the MAJOR.MINOR of the Python version to install: the effective lower bound.
+//
+// A requires-python is a comma-separated list of clauses in any order (e.g.
+// "<3.13,>=3.10"). Each clause is classified by operator:
+//   - lower-bound / pinning (>=, >, ==, ~=, ===) or a bare MAJOR.MINOR with no
+//     operator establishes a floor;
+//   - upper-bound / exclusion (<, <=, !=) does not — those versions are capped
+//     or forbidden and must never be installed.
+//
+// The result is the highest floor across all floor clauses (so ">=3.8,>=3.11"
+// yields 3.11, the version that satisfies every clause). A spec with no floor
+// clause at all (e.g. "<3.13" or "!=3.12") is an error rather than a guess.
+func PythonMinorFromRequires(requiresPython string) (string, error) {
+	bestMajor, bestMinor := -1, -1
+	sawClause := false
+	for clause := range strings.SplitSeq(requiresPython, ",") {
+		clause = strings.TrimSpace(clause)
+		if clause == "" {
+			continue
+		}
+		m := clauseRe.FindStringSubmatch(clause)
+		if m == nil {
+			continue
+		}
+		sawClause = true
+		op := m[1]
+		// Upper-bound and exclusion operators never establish a floor.
+		if op == "<" || op == "<=" || op == "!=" {
+			continue
+		}
+		major, _ := strconv.Atoi(m[2])
+		minor, _ := strconv.Atoi(m[3])
+		hasPatch := m[4] != ""
+		// A strict ">" with no patch excludes the whole given minor series (PEP 440:
+		// ">3.10" matches neither 3.10 nor any 3.10.x), so the lowest installable
+		// minor is the next one up. But ">3.10.5" is still satisfied by 3.10.6, so a
+		// patch-qualified strict bound leaves the minor unchanged.
+		if op == ">" && !hasPatch {
+			minor++
+		}
+		if major > bestMajor || (major == bestMajor && minor > bestMinor) {
+			bestMajor, bestMinor = major, minor
+		}
+	}
+	if bestMajor >= 0 {
+		return fmt.Sprintf("%d.%d", bestMajor, bestMinor), nil
+	}
+	if sawClause {
+		return "", fmt.Errorf("requires-python %q has no lower bound to install from", requiresPython)
+	}
+	return "", fmt.Errorf("cannot parse python version from %q", requiresPython)
+}

libs/localenv/envkey_test.go

@@ -0,0 +1,67 @@
+package localenv
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEnvKeyForServerless(t *testing.T) {
+	for _, in := range []string{"4", "v4", "V4"} {
+		assert.Equal(t, "serverless/serverless-v4", EnvKeyForServerless(in))
+	}
+}
+
+func TestEnvKeyForSparkVersion(t *testing.T) {
+	assert.Equal(t, "dbr/15.4.x-scala2.12", EnvKeyForSparkVersion("15.4.x-scala2.12"))
+}
+
+func TestPythonMinorFromRequires(t *testing.T) {
+	cases := map[string]string{
+		"==3.12.*": "3.12",
+		">=3.12":   "3.12",
+		"==3.12.3": "3.12",
+		"~=3.11":   "3.11",
+		// Multi-clause specifiers: the lower bound is the version to install,
+		// regardless of clause order. Taking the first number would pick the
+		// excluded upper bound (e.g. 3.13 from "<3.13").
+		"<3.13,>=3.10":  "3.10",
+		">=3.10,<3.13":  "3.10",
+		">=3.10, <3.13": "3.10",
+		"<4.0,>=3.9":    "3.9",
+		"===3.11":       "3.11",
+		// The effective floor is the HIGHEST lower bound, regardless of order.
+		">=3.8,>=3.11": "3.11",
+		">=3.11,>=3.8": "3.11",
+		// A bare floor alongside an exclusion is still a floor.
+		"!=3.11,3.12":   "3.12",
+		"3.12,!=3.12.4": "3.12",
+		// Bare version with no operator.
+		"3.12": "3.12",
+		// Whitespace and patch components tolerated.
+		">= 3.10 , < 3.13": "3.10",
+		// Strict ">" with no patch excludes the whole minor series (PEP 440), so
+		// the floor is the next minor up.
+		">3.10":       "3.11",
+		">3.10,<3.13": "3.11",
+		">=3.9,>3.10": "3.11",
+		// Strict ">" WITH a patch does not exclude the minor series: 3.10.6
+		// satisfies ">3.10.5", so the floor stays 3.10.
+		">3.10.5":       "3.10",
+		">3.10.5,<3.13": "3.10",
+		">=3.10.2":      "3.10",
+	}
+	for in, want := range cases {
+		got, err := PythonMinorFromRequires(in)
+		require.NoError(t, err)
+		assert.Equal(t, want, got, "input %q", in)
+	}
+
+	// No usable floor: only upper-bound / exclusion clauses. Must error rather
+	// than select a forbidden/capped version.
+	for _, in := range []string{"<3.13", "<=3.12", "!=3.12", "<3.13,!=3.12", "garbage", ""} {
+		_, err := PythonMinorFromRequires(in)
+		assert.Error(t, err, "input %q must error", in)
+	}
+}

libs/localenv/result.go

@@ -0,0 +1,195 @@
+package localenv
+
+import "fmt"
+
+// Command path components, defined once so a rename touches a single place
+// (spec §0 / invariant 8 / scenario 21). The cmd layer builds the Cobra
+// command tree from CommandGroup/CommandSubgroup/CommandVerb; the --json
+// "command" field uses CommandName. No other string re-spells the command path.
+const (
+	CommandGroup    = "local-env"
+	CommandSubgroup = "python"
+	CommandVerb     = "sync"
+	CommandName     = CommandGroup + " " + CommandSubgroup + " " + CommandVerb
+
+	// SchemaVersion is the version of the --json output contract (spec §6).
+	// Bump it on any breaking change to the JSON shape.
+	SchemaVersion = 1
+)
+
+// Mode is the provisioning mode: a full environment (default) or the
+// constraints-only variant that omits the databricks-connect dependency.
+type Mode int
+
+const (
+	ModeDefault Mode = iota
+	ModeConstraintsOnly
+)
+
+// String returns the JSON/text spelling of the mode ("default" | "constraints-only").
+func (m Mode) String() string {
+	if m == ModeConstraintsOnly {
+		return "constraints-only"
+	}
+	return "default"
+}
+
+// PhaseName is a canonical execution phase (spec §3 / §6). The set is fixed and
+// ordered; the --json "phases" array reports every phase in this order.
+type PhaseName string
+
+const (
+	PhasePreflight PhaseName = "preflight"
+	PhaseResolve   PhaseName = "resolve"
+	PhaseFetch     PhaseName = "fetch"
+	PhaseMerge     PhaseName = "merge"
+	PhaseProvision PhaseName = "provision"
+	PhaseValidate  PhaseName = "validate"
+)
+
+// Phase status values (spec §6.2).
+const (
+	StatusOK      = "ok"
+	StatusError   = "error"
+	StatusPending = "pending"
+)
+
+// ErrorCode is a stable failure-class identifier surfaced in --json error.code
+// (spec §7). Values are compared via the ErrorCode constants, never by
+// string-matching messages, and are defined once here.
+type ErrorCode string
+
+const (
+	ErrNoTarget           ErrorCode = "E_NO_TARGET"
+	ErrManagerUnsupported ErrorCode = "E_MANAGER_UNSUPPORTED"
+	ErrUvMissing          ErrorCode = "E_UV_MISSING"
+	ErrNotWritable        ErrorCode = "E_NOT_WRITABLE"
+	ErrResolve            ErrorCode = "E_RESOLVE"
+	ErrEnvUnsupported     ErrorCode = "E_ENV_UNSUPPORTED"
+	ErrFetch              ErrorCode = "E_FETCH"
+	ErrWrite              ErrorCode = "E_WRITE"
+	ErrMerge              ErrorCode = "E_MERGE"
+	ErrPythonInstall      ErrorCode = "E_PYTHON_INSTALL"
+	ErrProvision          ErrorCode = "E_PROVISION"
+	ErrValidate           ErrorCode = "E_VALIDATE"
+)
+
+// PipelineError is a failure carrying a stable code, the phase at which it
+// occurred, and whether disk was mutated before the failure. It marshals to the
+// --json error object (spec §6.2). Code and FailurePhase are the stable
+// contract; Err holds the wrapped cause for errors.Is/As and is not serialized.
+type PipelineError struct {
+	Code         ErrorCode `json:"code"`
+	FailurePhase PhaseName `json:"failurePhase"`
+	Msg          string    `json:"message"`
+	DiskMutated  bool      `json:"diskMutated"`
+	Err          error     `json:"-"`
+}
+
+func (e *PipelineError) Error() string {
+	if e.Err != nil {
+		return e.Msg + ": " + e.Err.Error()
+	}
+	return e.Msg
+}
+
+func (e *PipelineError) Unwrap() error {
+	return e.Err
+}
+
+// NewError creates a PipelineError with a code and message. FailurePhase and
+// DiskMutated are filled in by the pipeline when it records the failure. The
+// message is formatted with fmt.Sprintf(format, args...); err may be nil.
+func NewError(code ErrorCode, err error, format string, args ...any) *PipelineError {
+	return &PipelineError{
+		Code: code,
+		Msg:  fmt.Sprintf(format, args...),
+		Err:  err,
+	}
+}
+
+// TargetInfo is the resolved compute target (spec §6 "target"). Source records
+// which of the four precedence sources was used. SparkVersion is the raw cluster
+// runtime string the resolver read; it is folded into EnvKey (dbr/<SparkVersion>)
+// and is not part of the JSON contract, kept only as intermediate resolver state.
+type TargetInfo struct {
+	Source            string `json:"source"`
+	ClusterID         string `json:"clusterId,omitempty"`
+	ServerlessVersion string `json:"serverlessVersion,omitempty"`
+	EnvKey            string `json:"envKey"`
+
+	SparkVersion string `json:"-"`
+}
+
+// ResolvedInfo is the resolved environment definition (spec §6 "resolved").
+// DBConnectVersion is omitted in constraints-only mode.
+type ResolvedInfo struct {
+	PythonVersion    string `json:"pythonVersion"`
+	DBConnectVersion string `json:"dbconnectVersion,omitempty"`
+	ArtifactSource   string `json:"artifactSource"`
+}
+
+// Plan describes the changes a --check run would apply (spec §6.3).
+// ChangedRegions is retained for text output only and is not serialized.
+type Plan struct {
+	WouldWrite         string `json:"wouldWrite"`
+	WouldBackup        string `json:"wouldBackup,omitempty"`
+	WouldInstallPython string `json:"wouldInstallPython,omitempty"`
+	Diff               string `json:"diff"`
+
+	ChangedRegions []string `json:"-"`
+}
+
+// PhaseStatus is one entry in the --json "phases" array (spec §6). Detail is
+// used for human-readable text output only and is not serialized.
+type PhaseStatus struct {
+	Phase  PhaseName `json:"phase"`
+	Status string    `json:"status"`
+
+	Detail string `json:"-"`
+}
+
+// Warning is a non-fatal advisory surfaced in --json "warnings" (spec §6).
+type Warning struct {
+	Code    string `json:"code"`
+	Message string `json:"message"`
+}
+
+// Result is the full outcome of a sync run and the root of the --json object
+// (spec §6). Field order matches the spec's schema so JSON key order is stable.
+//
+// Phases and Warnings are non-omitempty slices, so they must always be non-nil
+// before marshalling or the --json contract would emit "null" instead of "[]" —
+// a distinction that trips JSON consumers and golden diffs. Construct a Result
+// with NewResult (or otherwise seed both) rather than a bare Result{} literal.
+type Result struct {
+	SchemaVersion int            `json:"schemaVersion"`
+	Command       string         `json:"command"`
+	OK            bool           `json:"ok"`
+	Mode          string         `json:"mode"`
+	DryRun        bool           `json:"dryRun"`
+	Target        *TargetInfo    `json:"target,omitempty"`
+	Resolved      *ResolvedInfo  `json:"resolved,omitempty"`
+	Greenfield    bool           `json:"greenfield"`
+	Plan          *Plan          `json:"plan,omitempty"`
+	VenvPath      string         `json:"venvPath,omitempty"`
+	Phases        []PhaseStatus  `json:"phases"`
+	Warnings      []Warning      `json:"warnings"`
+	Error         *PipelineError `json:"error"`
+	BackupPath    string         `json:"backupPath,omitempty"`
+	// DurationMs is part of the §6 contract but reserved for now: the pipeline
+	// does not measure wall time (a real clock would make acceptance goldens
+	// non-deterministic), so it is always emitted as 0 until timing is wired
+	// through a clock the tests can control.
+	DurationMs int64 `json:"durationMs"`
+}
+
+// NewResult returns a Result with the non-omitempty slice fields initialized to
+// empty (non-nil) slices, so the --json output always renders "phases": [] and
+// "warnings": [] rather than "null". Callers fill in the remaining fields.
+func NewResult() *Result {
+	return &Result{
+		Phases:   []PhaseStatus{},
+		Warnings: []Warning{},
+	}
+}

libs/localenv/result_test.go

@@ -0,0 +1,45 @@
+package localenv
+
+import (
+	"encoding/json"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPipelineErrorWrapsAndExposesCode(t *testing.T) {
+	base := errors.New("boom")
+	err := NewError(ErrFetch, base, "fetch %s", "x")
+	assert.Equal(t, "fetch x: boom", err.Error())
+	assert.Equal(t, ErrFetch, err.Code)
+	assert.ErrorIs(t, err, base)
+}
+
+func TestModeString(t *testing.T) {
+	assert.Equal(t, "default", ModeDefault.String())
+	assert.Equal(t, "constraints-only", ModeConstraintsOnly.String())
+}
+
+func TestCommandName(t *testing.T) {
+	// The --json "command" field and all help text derive from these; the
+	// three-part path must join to the full command a user types.
+	assert.Equal(t, "local-env python sync", CommandName)
+}
+
+func TestNewResultEmitsEmptyArraysNotNull(t *testing.T) {
+	// The --json contract requires phases/warnings to render as [] not null;
+	// NewResult seeds them so consumers and golden diffs see a stable shape.
+	b, err := json.Marshal(NewResult())
+	require.NoError(t, err)
+	s := string(b)
+	assert.Contains(t, s, `"phases":[]`)
+	assert.Contains(t, s, `"warnings":[]`)
+	assert.NotContains(t, s, `"phases":null`)
+	assert.NotContains(t, s, `"warnings":null`)
+	// A bare Result{} literal is the shape NewResult exists to avoid.
+	bare, err := json.Marshal(&Result{})
+	require.NoError(t, err)
+	assert.Contains(t, string(bare), `"phases":null`, "sanity: bare literal is the null case")
+}