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Allow SHA-256 digests in container image references #3352

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Merged
lpcox merged 3 commits into from
Apr 8, 2026
+55 −4
Merged

Allow SHA-256 digests in container image references #3352

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f189598
Initial plan
Copilot Apr 8, 2026
7196ef4
Allow SHA-256 digests in container image references
Copilot Apr 8, 2026
86b59ae
Update error hint and schema description to mention @sha256 digest su…
Copilot Apr 8, 2026
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4 changes: 2 additions & 2 deletions internal/config/schema/mcp-gateway-config.schema.json
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Original file line number Diff line number Diff line change
Expand Up @@ -74,9 +74,9 @@
},
"container": {
"type": "string",
"description": "Container image for the MCP server (e.g., 'ghcr.io/example/mcp-server:latest'). This field is required for stdio servers per MCP Gateway Specification section 4.1.2.",
"description": "Container image for the MCP server (e.g., 'ghcr.io/example/mcp-server:latest' or 'ghcr.io/example/mcp-server@sha256:<digest>'). This field is required for stdio servers per MCP Gateway Specification section 4.1.2.",
"minLength": 1,
"pattern": "^[a-zA-Z0-9][a-zA-Z0-9./_-]*(:([a-zA-Z0-9._-]+|latest))?$"
"pattern": "^[a-zA-Z0-9][a-zA-Z0-9./_-]*(:([a-zA-Z0-9._-]+|latest))?(@sha256:[a-fA-F0-9]{64})?$"
},
"entrypoint": {
"type": "string",
Expand Down
4 changes: 2 additions & 2 deletions internal/config/validation_schema.go
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Expand Up @@ -59,7 +59,7 @@ func isTransientHTTPError(statusCode int) bool {

var (
// Compile regex patterns from schema for additional validation
containerPattern = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9./_-]*(:([a-zA-Z0-9._-]+|latest))?$`)
containerPattern = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9./_-]*(:([a-zA-Z0-9._-]+|latest))?(@sha256:[a-fA-F0-9]{64})?$`)
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Copilot AI Apr 8, 2026

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Now that digest-pinned references are accepted, the container validation error hint should include an example with an @sha256:<64-hex> suffix; otherwise users who provide a digest will still see guidance that implies only :tag is supported.

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urlPattern = regexp.MustCompile(`^https?://.+`)
mountPattern = regexp.MustCompile(`^[^:]+:[^:]+:(ro|rw)$`)
domainVarPattern = regexp.MustCompile(`^\$\{[A-Z_][A-Z0-9_]*\}$`)
Expand Down Expand Up @@ -506,7 +506,7 @@ func validateStringPatterns(stdinCfg *StdinConfig) error {
if server.Container != "" && !containerPattern.MatchString(server.Container) {
return rules.InvalidPattern("container", server.Container,
fmt.Sprintf("%s.container", jsonPath),
"Use a valid container image format (e.g., 'ghcr.io/owner/image:tag' or 'owner/image:latest')")
"Use a valid container image format (e.g., 'ghcr.io/owner/image:tag', 'owner/image:latest', or 'ghcr.io/owner/image:tag@sha256:<digest>')")
}

// Validate mount patterns
Expand Down
24 changes: 24 additions & 0 deletions internal/config/validation_schema_test.go
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Expand Up @@ -365,6 +365,30 @@ func TestValidateStringPatterns(t *testing.T) {
},
shouldErr: false,
},
{
name: "valid container pattern - tag with sha256 digest",
config: &StdinConfig{
MCPServers: map[string]*StdinServerConfig{
"test": {
Type: "stdio",
Container: "ghcr.io/owner/image:v1.2.3@sha256:2763823c67a0adca3fce6e3bdfee41a674e3bf22f0e6b2eee94ed3a72ebcd519",
},
},
},
shouldErr: false,
},
{
name: "valid container pattern - sha256 digest only",
config: &StdinConfig{
MCPServers: map[string]*StdinServerConfig{
"test": {
Type: "stdio",
Container: "ghcr.io/owner/image@sha256:2763823c67a0adca3fce6e3bdfee41a674e3bf22f0e6b2eee94ed3a72ebcd519",
},
},
},
shouldErr: false,
},
{
name: "invalid container pattern - starts with special char",
config: &StdinConfig{
Expand Down
27 changes: 27 additions & 0 deletions internal/config/validation_string_patterns_test.go
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Expand Up @@ -64,6 +64,19 @@ func TestValidateStringPatternsComprehensive(t *testing.T) {
serverType: "",
shouldError: false,
},
// Valid container patterns with SHA-256 digest
{
name: "valid container with tag and sha256 digest",
container: "ghcr.io/github/github-mcp-server:v0.32.0@sha256:2763823c67a0adca3fce6e3bdfee41a674e3bf22f0e6b2eee94ed3a72ebcd519",
serverType: "stdio",
shouldError: false,
},
{
name: "valid container with sha256 digest only",
container: "ghcr.io/github/github-mcp-server@sha256:2763823c67a0adca3fce6e3bdfee41a674e3bf22f0e6b2eee94ed3a72ebcd519",
serverType: "stdio",
shouldError: false,
},
// Invalid container patterns
{
name: "invalid container starts with special char",
Expand All @@ -86,6 +99,20 @@ func TestValidateStringPatternsComprehensive(t *testing.T) {
shouldError: true,
errorField: "container",
},
{
name: "invalid container sha256 digest too short",
container: "ghcr.io/github/github-mcp-server@sha256:short",
serverType: "stdio",
shouldError: true,
errorField: "container",
},
{
name: "invalid container wrong digest algorithm",
container: "ghcr.io/github/github-mcp-server@md5:2763823c67a0adca3fce6e3bdfee41a674e3bf22f0e6b2eee94ed3a72ebcd519",
serverType: "stdio",
shouldError: true,
errorField: "container",
},
{
name: "invalid container empty string accepted (empty is valid)",
container: "",
Expand Down
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