Dockerize native engine builds. (pantsbuild#4554)

Fixes pantsbuild#4541

Problem

Native engine builds dynamically link against libc. This can be problematic if the published binaries are built on a platform with a newer version of libc than the runtime platform.

Solution

In order for the native engine to run on older platforms, we need to link against the oldest reasonable libc at binary creation time and rely on forward compatibility/OS compatibility libraries to cover more possible platforms.

Result

More widely compatible native engine binaries.

.travis.yml

@@ -16,6 +16,8 @@ env:
     - secure: qid/ot1XIWOpNaN+RhgdJq8IEajcpHI5EFvy2ywkYHJO2hKYawyX2M4gFd0Vq8+xmeGB4MUmpPW8D8gijLi5JB+0aZ3+5JHs5r9NWkK7HVMpVnok3CywknzXBgeo+UoEQv9ugYvRr1Sm9Dj9IezAhM0tw1uS95Ap+JLbnWFB830=
 
 before_cache:
+  # Ensure permissions to do the below removals, which happen with or without caching enabled.
+  - sudo chown -R travis:travis "${HOME}" "${TRAVIS_BUILD_DIR}"
   # Kill all python bytecode in our cached venvs.  Some files appear to
   # get bytecode compiled in non-yet-understood circumstances leading to
   # a full cache re-pack due to new bytecode files.
@@ -56,12 +58,40 @@ matrix:
     - os: osx
       language: generic
       env:
-        - SHARD="OSX"
+        - SHARD="OSX Bintray Builder"
       script:
-        - ./pants --version
-      after_success:
         - ./build-support/bin/native/generate-bintray-manifest.sh
 
+    - os: linux
+      dist: trusty
+      sudo: required
+      # Docker runs will write files as root, so avoid caching for this shard.
+      cache: false
+      services:
+        - docker
+      language: python
+      python: "2.7.13"
+      env:
+        - SHARD="Linux Bintray Builder"
+        # Use the standard python manylinux image for ideal binary compatibility.
+        - DOCKER_IMAGE="quay.io/pypa/manylinux1_x86_64"
+      before_install:
+        # Remove any Ubuntu binary cruft before building.
+        - git clean -fdx
+        - rm -rf ~/.cache/pants
+        - docker pull $DOCKER_IMAGE
+      script:
+        # Map virtual mount paths 1:1 to simulate running in-place in travis.
+        - docker run --rm -t
+          -v "${TRAVIS_BUILD_DIR}:${TRAVIS_BUILD_DIR}"
+          -v "${HOME}:${HOME}"
+          -e "HOME=${HOME}"
+          "${DOCKER_IMAGE}"
+          sh -c "
+            export PATH=/opt/python/cp27-cp27mu/bin:/opt/rh/devtoolset-2/root/usr/bin:${PATH} ;
+            cd $TRAVIS_BUILD_DIR && ./build-support/bin/native/generate-bintray-manifest.sh
+          "
+
     - os: linux
       dist: trusty
       sudo: required
@@ -89,8 +119,6 @@ matrix:
         - SHARD="Various pants self checks"
       script:
         - ./build-support/bin/ci.sh -x -cjlpn 'Various pants self checks'
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -119,8 +147,6 @@ matrix:
         - SHARD="Unit tests for pants and pants-plugins - shard 1"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrcn -u 0/2 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -149,8 +175,6 @@ matrix:
         - SHARD="Unit tests for pants and pants-plugins - shard 2"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrcn -u 1/2 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -179,8 +203,6 @@ matrix:
         - SHARD="Python contrib tests"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrcjlp "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -209,8 +231,6 @@ matrix:
         - SHARD="Python integration tests for pants - shard 1"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 0/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -239,8 +259,6 @@ matrix:
         - SHARD="Python integration tests for pants - shard 2"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 1/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -269,8 +287,6 @@ matrix:
         - SHARD="Python integration tests for pants - shard 3"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 2/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -299,8 +315,6 @@ matrix:
         - SHARD="Python integration tests for pants - shard 4"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 3/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -329,8 +343,6 @@ matrix:
         - SHARD="Python integration tests for pants - shard 5"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 4/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -359,8 +371,6 @@ matrix:
         - SHARD="Python integration tests for pants - shard 6"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 5/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
     - os: linux
       dist: trusty
@@ -389,20 +399,17 @@ matrix:
         - SHARD="Python integration tests for pants - shard 7"
       script:
         - ./build-support/bin/ci.sh -x -fkmsrjlpn -i 6/7 "${SHARD}"
-      after_success:
-        - ./build-support/bin/native/generate-bintray-manifest.sh
 
 deploy:
   # See: https://docs.travis-ci.com/user/deployment/bintray/
   provider: bintray
-
   # NB: This is generated in after_success in each shard above.
   file: ./native-engine.bintray.json
-
   user: ${BINTRAY_USER}
   key: ${BINTRAY_KEY}
   dry-run: false
   on:
+    condition: -f ./native-engine.bintray.json
     # NB: Deploys are always tagged as part of the deploy process encoded in
     # `build-support/bin/release.sh`, so this ensures we release an appropriate native engine binary
     # for all releases. Unfortunately, CI only runs after the release tag hits origin and so there