feat: lazy validation, only resolve expressions for the active context (#148)

Author: MattDevy

src/config/loader.ts

@@ -6,12 +6,16 @@
 /**
  * Configuration file discovery, loading, validation, and context resolution.
  *
- * Pipeline:
+ * Pipeline (lazy validation):
  * 1. Discover config file in home directory (or via --config-file / ELASTIC_CLI_CONFIG_FILE)
- * 2. Resolve expressions in config values (e.g. $(env:VAR), $(cmd:...), $(keychain:...))
- * 3. Validate resolved config with Zod schemas
- * 4. Resolve the active context (default or --use-context override)
- * 5. Return typed ResolvedConfig to command handlers
+ * 2. Structural validation of the outer config shape (without resolving expressions)
+ * 3. Resolve context name (default or --use-context override)
+ * 4. Resolve expressions only in the active context and commands section
+ * 5. Validate active context with full Zod schemas
+ * 6. Return typed ResolvedConfig to command handlers
+ *
+ * Only the active context's expressions are resolved, so inactive contexts
+ * with unset environment variables or missing files will not cause failures.
  *
  * Supports:
  * - Home-directory discovery (~/.elasticrc.yml and variants)
@@ -26,7 +30,7 @@ import { homedir } from 'node:os'
 import { extname, join } from 'node:path'
 import { z } from 'zod'
 import { parse as parseYaml } from 'yaml'
-import { ConfigFileSchema } from './schema.ts'
+import { ContextSchema, CommandPolicySchema, StructuralConfigSchema } from './schema.ts'
 import { resolveExpressions } from './resolvers.ts'
 import type { ConfigFile, ResolvedConfig, ResolvedContext } from './types.ts'
 
@@ -128,14 +132,19 @@ export interface LoadConfigErr { ok: false, error: { message: string } }
 export type LoadConfigResult = LoadConfigOk | LoadConfigErr
 
 /**
- * Full config loading pipeline: discover/load → validate → resolve context.
+ * Full config loading pipeline with lazy expression resolution.
  *
  * Steps:
  * 1. Discover or resolve config file path, then read and parse it
- * 2. Resolve expressions in string values (env, cmd, keychain)
- * 3. Validate with `ConfigFileSchema` (Zod)
- * 4. Resolve the active context (from `contextName` override or `current_context`)
- * 5. Return a typed `ResolvedConfig`
+ * 2. Structural validation (shape only, no expression resolution)
+ * 3. Resolve context name (from `contextName` override or `current_context`)
+ * 4. Extract active context raw data + commands section
+ * 5. Resolve expressions only in the active context and commands
+ * 6. Validate active context with ContextSchema, commands with CommandPolicySchema
+ * 7. Return a typed `ResolvedConfig`
+ *
+ * Only the active context's expressions are resolved, so inactive contexts
+ * with unset environment variables or missing files will not cause failures.
  *
  * All failure modes return `{ ok: false, error: { message } }` -- never throw.
  *
@@ -172,27 +181,19 @@ export async function loadConfig (options: LoadConfigOptions = {}): Promise<Load
     return { ok: false, error: { message } }
   }
 
-  // Step 2: resolve expressions in string values
-  try {
-    raw = await resolveExpressions(raw)
-  } catch (err) {
-    const message = err instanceof Error ? err.message : String(err)
-    return { ok: false, error: { message: `Failed to resolve config expressions: ${message}` } }
-  }
-
-  // Step 3: validate with Zod
-  const parsed = ConfigFileSchema.safeParse(raw)
-  if (!parsed.success) {
-    return { ok: false, error: { message: z.prettifyError(parsed.error) } }
+  // Step 2: structural validation (shape only, no deep context validation)
+  const structural = StructuralConfigSchema.safeParse(raw)
+  if (!structural.success) {
+    return { ok: false, error: { message: z.prettifyError(structural.error) } }
   }
 
-  const config = parsed.data
+  const { current_context, contexts, commands: rawCommands } = structural.data
 
-  // Step 4: resolve context name (--use-context override or current_context from file)
-  const resolvedContextName = contextName ?? config.current_context
+  // Step 3: resolve context name (--use-context override or current_context from file)
+  const resolvedContextName = contextName ?? current_context
 
-  if (!(resolvedContextName in config.contexts)) {
-    const available = Object.keys(config.contexts).join(', ')
+  if (!(resolvedContextName in contexts)) {
+    const available = Object.keys(contexts).join(', ')
     return {
       ok: false,
       error: {
@@ -201,6 +202,41 @@ export async function loadConfig (options: LoadConfigOptions = {}): Promise<Load
     }
   }
 
-  // Step 5: resolve and return
-  return { ok: true, value: resolveContext(config, resolvedContextName) }
+  // Step 4: resolve expressions only in active context and commands (in parallel)
+  let resolvedRawContext: unknown
+  let resolvedRawCommands: unknown
+  try {
+    [resolvedRawContext, resolvedRawCommands] = await Promise.all([
+      resolveExpressions(contexts[resolvedContextName], `contexts.${resolvedContextName}`),
+      rawCommands != null ? resolveExpressions(rawCommands, 'commands') : undefined,
+    ])
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err)
+    return { ok: false, error: { message: `Failed to resolve config expressions: ${message}` } }
+  }
+
+  // Step 5: validate active context and commands with full schemas
+  const contextParsed = ContextSchema.safeParse(resolvedRawContext)
+  if (!contextParsed.success) {
+    return { ok: false, error: { message: z.prettifyError(contextParsed.error) } }
+  }
+
+  let commands: ConfigFile['commands']
+  if (resolvedRawCommands != null) {
+    const commandsParsed = CommandPolicySchema.safeParse(resolvedRawCommands)
+    if (!commandsParsed.success) {
+      return { ok: false, error: { message: z.prettifyError(commandsParsed.error) } }
+    }
+    commands = commandsParsed.data
+  }
+
+  // Step 6: build and return ResolvedConfig
+  const ctx = contextParsed.data
+  const resolved: ResolvedContext = {}
+  if (ctx.elasticsearch != null) resolved.elasticsearch = ctx.elasticsearch
+  if (ctx.kibana != null) resolved.kibana = ctx.kibana
+  if (ctx.cloud != null) resolved.cloud = ctx.cloud
+  const result: ResolvedConfig = { context: resolved }
+  if (commands != null) result.commands = commands
+  return { ok: true, value: result }
 }

src/config/schema.ts

@@ -82,3 +82,18 @@ export const ConfigFileSchema = z
     (cfg) => cfg.current_context in cfg.contexts,
     { error: 'current_context must reference an existing context key' }
   )
+
+/**
+ * Structural schema for first-pass validation before expression resolution.
+ * Validates the outer config shape (current_context, contexts keys, commands)
+ * without deeply validating context values (which may contain unresolved expressions).
+ */
+export const StructuralConfigSchema = z
+  .object({
+    current_context: z.string().min(1),
+    contexts: z.record(z.string(), z.record(z.string(), z.unknown())).refine(
+      (map) => Object.keys(map).length > 0,
+      { error: 'contexts must contain at least one entry' },
+    ),
+    commands: z.unknown().optional(),
+  })

test/config/loader.test.ts

@@ -449,6 +449,190 @@ commands:
   })
 })
 
+// ---------------------------------------------------------------------------
+// Lazy validation: only resolve expressions for the active context (#144)
+// ---------------------------------------------------------------------------
+
+describe('lazy validation: inactive context expressions are not resolved', () => {
+  const ACTIVE_VAR = 'ELASTIC_CLI_TEST_ACTIVE_KEY'
+  const INACTIVE_VAR = 'ELASTIC_CLI_TEST_INACTIVE_KEY'
+  let tmpDir: string
+
+  before(async () => {
+    tmpDir = await mkdtemp(join(tmpdir(), 'elastic-cli-lazy-'))
+  })
+  after(async () => {
+    delete process.env[ACTIVE_VAR]
+    delete process.env[INACTIVE_VAR]
+    await rm(tmpDir, { recursive: true })
+  })
+
+  it('succeeds when the active context resolves but an inactive context would fail', async () => {
+    process.env[ACTIVE_VAR] = 'active-api-key'
+    delete process.env[INACTIVE_VAR]
+    const yaml = `
+current_context: local
+contexts:
+  local:
+    elasticsearch:
+      url: http://localhost:9200
+      auth:
+        api_key: $(env:${ACTIVE_VAR})
+  staging:
+    elasticsearch:
+      url: https://staging.example.com:9200
+      auth:
+        api_key: $(env:${INACTIVE_VAR})
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-ok.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(result.ok, `expected ok, got: ${!result.ok ? result.error.message : ''}`)
+    if (!result.ok) return
+    assert.equal(
+      (result.value.context.elasticsearch!.auth as { api_key: string }).api_key,
+      'active-api-key'
+    )
+  })
+
+  it('still fails when the active context has an unresolvable expression', async () => {
+    delete process.env[ACTIVE_VAR]
+    delete process.env[INACTIVE_VAR]
+    const yaml = `
+current_context: local
+contexts:
+  local:
+    elasticsearch:
+      url: http://localhost:9200
+      auth:
+        api_key: $(env:${ACTIVE_VAR})
+  staging:
+    elasticsearch:
+      url: https://staging.example.com:9200
+      auth:
+        api_key: $(env:${INACTIVE_VAR})
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-fail.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(!result.ok, 'expected failure for unresolvable active context expression')
+    if (result.ok) return
+    assert.match(result.error.message, new RegExp(ACTIVE_VAR))
+  })
+
+  it('resolves expressions in the active context selected via --use-context', async () => {
+    process.env[INACTIVE_VAR] = 'staging-key'
+    delete process.env[ACTIVE_VAR]
+    const yaml = `
+current_context: local
+contexts:
+  local:
+    elasticsearch:
+      url: http://localhost:9200
+      auth:
+        api_key: $(env:${ACTIVE_VAR})
+  staging:
+    elasticsearch:
+      url: https://staging.example.com:9200
+      auth:
+        api_key: $(env:${INACTIVE_VAR})
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-override.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath, contextName: 'staging' })
+    assert.ok(result.ok, `expected ok with --use-context staging, got: ${!result.ok ? result.error.message : ''}`)
+    if (!result.ok) return
+    assert.equal(
+      (result.value.context.elasticsearch!.auth as { api_key: string }).api_key,
+      'staging-key'
+    )
+  })
+
+  it('still validates structural config shape (missing current_context)', async () => {
+    const yaml = `
+contexts:
+  local:
+    elasticsearch:
+      url: http://localhost:9200
+      auth:
+        api_key: some-key
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-no-current.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(!result.ok, 'should fail without current_context')
+  })
+
+  it('still validates structural config shape (empty contexts)', async () => {
+    const yaml = `
+current_context: local
+contexts: {}
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-empty-contexts.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(!result.ok, 'should fail with empty contexts')
+  })
+
+  it('rejects current_context that references a nonexistent context key', async () => {
+    const yaml = `
+current_context: nonexistent
+contexts:
+  local:
+    elasticsearch:
+      url: http://localhost:9200
+      auth:
+        api_key: some-key
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-bad-ref.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(!result.ok, 'should fail when current_context references missing key')
+    if (result.ok) return
+    assert.ok(result.error.message.includes('nonexistent'))
+  })
+
+  it('resolves expressions in commands section', async () => {
+    process.env[ACTIVE_VAR] = 'my-key'
+    const yaml = `
+current_context: local
+contexts:
+  local:
+    elasticsearch:
+      url: http://localhost:9200
+      auth:
+        api_key: $(env:${ACTIVE_VAR})
+commands:
+  allowed:
+    - ping
+    - elasticsearch.search
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-commands.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(result.ok, `expected ok, got: ${!result.ok ? result.error.message : ''}`)
+    if (!result.ok) return
+    assert.deepEqual(result.value.commands, { allowed: ['ping', 'elasticsearch.search'] })
+  })
+
+  it('validates active context with full schema after expression resolution', async () => {
+    process.env[ACTIVE_VAR] = 'resolved-key'
+    const yaml = `
+current_context: local
+contexts:
+  local:
+    elasticsearch:
+      url: not-a-valid-url
+      auth:
+        api_key: $(env:${ACTIVE_VAR})
+`.trimStart()
+    const configPath = join(tmpDir, 'lazy-bad-url.yml')
+    await writeFile(configPath, yaml)
+    const result = await loadConfig({ configPath })
+    assert.ok(!result.ok, 'should fail when active context has invalid URL after resolution')
+  })
+})
+
 describe('security: executable config formats are rejected', () => {
   let tmpDir: string
   before(async () => {