CI: Only push to cache when needed

.gitlab-ci.yml

@@ -6,11 +6,6 @@ stages:
   - image
 
 .rust_template: &rust_template
-  cache:
-    key: "$CI_COMMIT_REF_SLUG"
-    paths:
-      - cargo/
-      - target/
   before_script:
     - export CARGO_HOME="$CI_PROJECT_DIR/cargo"
     - rustup --version
@@ -20,6 +15,11 @@ stages:
 rust-nightly:
   stage: build
   image: rustlang/rust:nightly
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - cargo/
+      - target/
   <<: *rust_template
   script:
     - cargo build --verbose
@@ -27,6 +27,12 @@ rust-nightly:
 rust-nightly-test:
   stage: test
   image: rustlang/rust:nightly
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - cargo/
+      - target/
+    policy: pull
   <<: *rust_template
   script:
     - cargo test --verbose -j 1
@@ -34,6 +40,12 @@ rust-nightly-test:
 rust-nightly-fmt:
   stage: format
   image: rustlang/rust:nightly
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - cargo/
+      - target/
+    policy: pull
   <<: *rust_template
   script:
     - cargo fmt --all --verbose -- --check
@@ -41,6 +53,11 @@ rust-nightly-fmt:
 rust-nightly-clippy:
   stage: lint
   image: rustlang/rust:nightly
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - cargo/
+      - target/
   <<: *rust_template
   script:
     - cargo clippy --all --verbose -- -D warnings
@@ -50,6 +67,12 @@ rust-nightly-docker:
   image:
     name: gcr.io/kaniko-project/executor:debug
     entrypoint: [""]
+  cache:
+    key: "$CI_COMMIT_REF_SLUG"
+    paths:
+      - cargo/
+      - target/
+    policy: pull
   script:
     - mkdir -p /kaniko/.docker
     - echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json