https://github.com/linkerd/linkerd-await

A program that blocks on linkerd readiness
https://github.com/linkerd/linkerd-await

Last synced: 8 months ago
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A program that blocks on linkerd readiness

• Host: GitHub
• URL: https://github.com/linkerd/linkerd-await
• Owner: linkerd
• License: apache-2.0
• Created: 2019-03-23T21:04:06.000Z (about 7 years ago)
• Default Branch: main
• Last Pushed: 2025-09-29T17:48:47.000Z (9 months ago)
• Last Synced: 2025-09-29T19:37:33.475Z (9 months ago)
• Language: Rust
• Size: 470 KB
• Stars: 79
• Watchers: 9
• Forks: 17
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Codeowners: .github/CODEOWNERS

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README

          
# linkerd-await

A command-wrapper that polls Linkerd for readiness until it becomes ready and

only then executes a command.

## Usage

```text

linkerd-await 0.2.9

Wait for linkerd to become ready before running a program

Usage: linkerd-await [OPTIONS] [CMD] [ARGS]...

Arguments:

  [CMD]      The command to run after linkerd is ready

  [ARGS]...  Arguments to pass to CMD if specified

Options:

  -p, --port 

          The port of the local Linkerd proxy admin server [default: 4191]

  -b, --backoff 

          Time to wait after a failed readiness check [default: 1s]

  -S, --shutdown

          Forks the program and triggers proxy shutdown on completion

  -v, --verbose

          Causes linkerd-await to print an error message when disabled [env: LINKERD_AWAIT_VERBOSE=]

  -t, --timeout 

          Causes linked-await to fail when the timeout elapses before the proxy becomes ready

      --timeout-fatal[=]

          Controls whether a readiness timeout failure prevents CMD from running [default: true] [possible values: true, false]

  -h, --help

          Print help

  -V, --version

          Print version

```

## Examples

### Dockerfile

```dockerfile

# Create a base layer with linkerd-await from a recent release.

FROM docker.io/curlimages/curl:latest as linkerd

ARG LINKERD_AWAIT_VERSION=v0.3.0

RUN curl -sSLo /tmp/linkerd-await https://github.com/linkerd/linkerd-await/releases/download/release%2F${LINKERD_AWAIT_VERSION}/linkerd-await-${LINKERD_AWAIT_VERSION}-amd64 && \

    chmod 755 /tmp/linkerd-await

# Build your application with whatever environment makes sense.

FROM myapp-build as app

WORKDIR /app

RUN make build

# Package the application wrapped by linkerd-await. Note that the binary is

# static so it can be used in `scratch` images:

FROM scratch

COPY --from=linkerd /tmp/linkerd-await /linkerd-await

COPY --from=app /app/myapp /myapp

# In this case, we configure the proxy to be shutdown after `myapp` completes

# running. This is only really needed for jobs where the application is

# expected to complete on its own (namely, `Jobs` and `Cronjobs`)

ENTRYPOINT ["/linkerd-await", "--shutdown", "--"]

CMD  ["/myapp"]

```

### Disabling `linkerd-await` at runtime

The `LINKERD_AWAIT_DISABLED` (or `LINKERD_DISABLED`) environment variable can

be set to bypass `linkerd-await`'s readiness checks. This way,

`linkerd-await` may be controlled by overriding a default environment

variable:

```yaml

    # ...

    spec:

      containers:

        - name: myapp

          env:

            - name: LINKERD_AWAIT_DISABLED

              value: "Linkerd is disabled ;("

          # ...

```