Secrets
Dagger has built-in support for secrets — passwords, API keys, tokens — sourced from multiple providers. Secrets are never exposed in logs, written to container filesystems, or inserted into the cache.
Passing secrets
Secrets are passed to functions via provider URIs:
# From environment variables
dagger api call deploy --token=env:DEPLOY_TOKEN
# From files
dagger api call deploy --token=file:./secrets/token.txt
# From command output
dagger api call deploy --token=cmd:"aws sts get-session-token --query Token"
Providers
Environment variables
dagger api call my-function --secret=env:MY_SECRET
Reads the value of MY_SECRET from the host environment.
Files
dagger api call my-function --secret=file:/path/to/secret
Reads the secret from a file on the host.
Command output
dagger api call my-function --secret=cmd:"command to run"
Runs the command on the host and uses its stdout as the secret value.
HashiCorp Vault
Dagger can resolve secrets directly from Vault using the vault:// scheme. Only KVv2 mounts are supported.
shell dagger api call my-function --secret=vault://secret/foo/bar.token
Reads the token field of the KVv2 secret foo/bar from the secret mount.
URI format: vault://<mount>/<path>.<field> — the mount is the first path segment, the field is everything after the last dot.
Caching: by default, ttl is infinite. Add ?ttl=1h to cache the resolved value client-side for the given duration.
Authentication: requires the Dagger CLI to be authenticated with Vault via VAULT_ADDR, plus auth-method-specific variables:
VAULT_TOKEN— token authenticationVAULT_APPROLE_MOUNT_PATH,VAULT_APPROLE_ROLE_ID,VAULT_APPROLE_SECRET_ID— AppRole authenticationVAULT_OIDC_MOUNT_PATH,VAULT_OIDC_CALLBACK_PORT,VAULT_OIDC_ROLE,VAULT_OIDC_SKIP_BROWSER- OIDC authentication
1Password
dagger api call my-function --secret=op://vault-name/item-name/field
Reads from 1Password. Requires authentication via op signin.
AWS Secrets Manager
dagger api call my-function --secret=aws+sm://prod/my-secret
For JSON secrets, extract a specific field:
dagger api call my-function --secret=aws+sm://prod/database?field=password
Options: ?region=us-west-2, ?version=<id>, ?stage=AWSPREVIOUS.
AWS Parameter Store
dagger api call my-function --secret=aws+ps://prod/api-key
Reads the parameter /prod/api-key (the leading slash is added for you). SecureString parameters are automatically decrypted.
AWS authentication
Both AWS providers use the default credential chain: environment variables, shared credentials file (~/.aws/credentials), or IAM role (EC2, ECS, Lambda).
Set the region with AWS_REGION or the ?region= query parameter.
Google Cloud Secret Manager
dagger api call my-function --secret=gcp://my-secret
A bare name reads the secret from the project set by GCP_PROJECT_ID, GOOGLE_CLOUD_PROJECT, or GCLOUD_PROJECT. Use gcp://projects/PROJECT_ID/secrets/SECRET_NAME/versions/VERSION to specify the project and version explicitly. Authentication uses Application Default Credentials.
libsecret (GNOME Keyring)
dagger api call my-function --secret=libsecret://login/my-secret
Reads from the host's freedesktop.org Secret Service (e.g. GNOME Keyring) on Linux.
Safeguards
Dagger ensures secrets never leak:
- Logs: Secret values are redacted from all output
- Filesystem: Secrets are never written to container layers
- Cache: Operations using secrets are excluded from cache keys
If a workflow crashes, secrets remain protected.